The Legacy of Tube Preamplifier Designs – The Driving Output Stage I

Hello to everybody,

a last posting for this year is made with the intention to bring credit to the leavings of important figures which did die within the year, in the early beginning Ken Shindo and in autum Jean Constant Verdier. Ken Shindo is one of the few in the western hemisphere known japanese designers who did design a wide range of exceptional balanced and elaborated sounding tube amplifiers. As the most people might know, in Japan the evaluation of historic western tube equipment was paragon. They started to inspect, research. refine and outperform the classic examples made for the early professional broadcast or cinematographic use like WE. RCA, Altec, Klangfilm and others, while the western world got flooded with their cheap commercial electronic mass products from Pioneer, Sansui and others in the 1970ties years for home entertainment. Their particular asian appropriation of mastership thinking, their diligence and finally their conscientiousness made at the other end unique products possible, which collect more experiences in that field of expertise and are far ahead of other made product in the world of tube audio.

This article will be some sort of summery to my evaluations which I made within the last weeks in order find out about some basic influences of particular design topologies important with tube amplified output stages. It came into close inspection by a typical side accident which happened in November. I had a chance to listen to a original Kaneda preamplifier in a very elaborated audio chain, where a Line Magnetic LM22A/555W/597 horn system was driven by a Shindo power amplifier and a Monbrison preamplifier. It happened that we were talking about Kaneda preamps and it came to the point that I instantly got offered the chance to listen to a sample. Me was told that the (japanese) transistors inside normally love a long warmup time, – in every day use they never will be switched off… The Kaneda preamplifiers got popular in Europe through Jean Hiraga and the parisian Maison de L'Audiophile in the late 1970ties and early 1980ties, who brought this design topology from Japan. In these days the preamps got mostly sold as kits and have been highly praised as perfect alternatives to high priced tube amps mainly coming from the US in these days.

In order to get the Kaneda warmed up to best performance, we did wait for some hour before we switched over from the Monbrison. As we did before we did listen to digital streamed music material. This means we did listen to a fraction of both amplifiers, so only the output stage (line) and the power supply from each unit have been involved. During the warming up we did listen to the Shindo with a variety of program material, before we switched to the Kaneda unit.
To be honest, I would not have believed before what happened. The difference between both units was tremendous wide, more than that. Coming from the Shindo, the music was natural in a flow with all dynamic attributes right in place and loads of micro dynamic information (commonly named as air). With the Kaneda the music flow was stiff, almost grey and grainy, without any particular micro dynamic detail. It might be have been the temperature of the Kaneda, but even with a imaginable top condition it would not be assumable to difference out to a natural completeness shown by Shindos Monbrison. I was staggering and noticed that only one tube with its PSU was able to outperform and boost the Class A battery supplied Kaneda into a different world. Again a perfect example that Shindo did better than perfect know what he realizes. And in difference to the most other tube amplifier designers, he knows exactly how it has sound finally. His superiority was not alone the knowledge and experience with parts, components and topologies, it was mainly his aim to get the right decisions into order for a precisely aimed audible result, always having a perfect dynamic natural performance in mind.

After that unforeseen demonstration of superiority I went home deeply impressed how well Shindo implemented his output stage in his design. The most here reading, do know that I am into the merits of directly heated triodes in small signal stages since a decade. My long term approved preamplifier uses the Aa Weitverkehrsröhren, a design with some little restrictions (high output impedance) but so far best audible general performance I have used. I have been at a point were I did not want to question this design again. But this experience did do. It pointed out to the most questionable part, the output impedance of the driving line amp is tremendous important part of the complete sonic result. OK, thank you Ken Shindo for your advice, I will take another lecture as homework about this topic.

A typical professional US broadcast preamplifier as made by several companies like IPC, RCA, Pultec or similar with high mu input  stage 12AX7/ECC83 and paralleled 12AU7/ECC82 transformer coupled output stage in order to archive low impedance output (600 ohm or lower).

First of all I did work out theoretically all possible tubes which might be superior within such a design (output transformer with 600 Z secondary). For the beginning I did look up what will be available from my shelves, – what will be necessary to get. I had several output transformers for that reason lying around (different types of Lundahl LL1660, LL1680, its original UTC LS27 and a pair of Tango permalloy core 20K:10K/600) and for practical reasons I started with tubes I already own. The most output transformers are limited at 10K to 20K primary impedance when set to a realistic 600 Z output with reasonable DC in primary (5-20mA). A rule of thumb says that you need to calculate three to five times the internal resistance of the tube to find the best working value of the output transformer (example a 3K Ri of a given tube will match a 12K transformer primary side). A variant of design is to incorporate a additional anode choke (getting the OPT transformer off dc in its primary, but reintroduces a coupling capacitor). For that variants I will have a selection of Lundahl LL1667 air gapped chokes for 5 to 25 mA DC by hand.

Other than a producer of commercial amounts of units I can set my interest to the best components available, I don't have to take questions of availability or single prices into account when I decide. All my tube amplified life I was a great fanatic of the RCA red base series of tubes (5691/6SL7GT, 5692/6SN/GT, 5693/6SJ7GT) which were originally made for the cruise missile control units and are extremely mechanically rugged versions with double heater consumption of the standard octal versions (600mA does not make them a universal replacement). Even their prices have always been literally skyrocketed and so you rarely will see any commercial made audio amp designed with them (Bruce Moores Luminiscence), but I believe they are some of the very best made tubes ever. In all these years these tubes have outperformed everything similar in all my preamplifiers, 12AY7, ECC82 or 802s, Telefunken, Mullard, – everything!
Here now the 5692 with internal impedance of 8K is a candidate for paralleling their two units to half their internal impedance. As well a true legend from the German Post, the C3g with 3K ripple in triode mode is a ideal contender for such implementation. Western Electrics 417A with 1.6K might be a true choice as some other space age tubes like 5687, 6463, 6386 have to be taken into account. But as well real power output tubes like 6F6G, EL84 and similar types will do the job. All named tubes are indirectly heated types, but there are a few DHTs as well which might outperform the late high-tech stuff? The Ce/Cas Weitverkehrsröhren with 4K ripple, the british pedants 3A/110-B and 3A/101-B and of course the Western Electric tennis ball battery tubes are matching perfectly, but you need to find them since they are exceptional rare. As there are little better known small power triodes like 801A, 2A3, etc., but they make output transformers necessary with higher DC capability in the primary winding or the use of the parafeed design together with a choke load.

To make such a comparison meaningful I know that the power supply might take an important part at the final result. So I arranged three different interchangeable power supplies within each setup.

First my standard PSU with AZ12 (mesh plates), all oil paper capacitors and several chokes in the HV rail and a selenium rectified LV supply with chokes is a complex and huge unit. All Transformers are hermetically sealed oil filled types. The anode supply is regulated and stabilized with two tubes as three active units.
Second a industrial type PSU with Selenium HV rectifier and highly regulated and stabilized with four tubes and AC low voltage supply is a alternative solution.
Third a standard supply without regulation and stabilization, just choke and capacitor filtered. LV selenium rectified and RC-filter rail is another option.

With all supplies I have the chance to adjust the anode supply widely, so that any tube from my range can be optimized with anode voltages between 150 to 230 volts. So I started to install identical connection plugs to each unit, which gives a flying change during evaluation a chance.

The results of my comparisons are nothing less than remarkable and expressive, they gave me a deep insight into the effects, requirements and influences of each topology. The optimal working point of the tube itself, the adaption and matching of the output transformer, the influence of different generated anode voltages and as well different filament supplies. And finally the tube itself and its character in the final soundstage. As little shortcut to the end it can be said, the tube itself has a highly overrated position to the final result.

Read on soon, Volker

Natural vs. Analogue vs. Digital vs. Fraunhofer Algorithm processed Music IV

Hello to everybody at the christmas holidays,

I will try now to finalize my series of articles about different recording and storage methods of audio information. So far I have tried to describe the holy religious believe into the audible improved qualities of analog mediums like vinyl records or reel tape. As well I did start to describe my experiences with digital stored information and tried as well to difference out a variety of different sampling and word length formats. I did try to describe arguments of availability for different stored formats, the massive influence of hardware to the performance and their comfort of use. Today I want to find final arguments about these topics, since some sort of serious discussion will not start throughout this blog, even when I did try find provocative thesis's and arguments for one or another strategy.

As I did describe before, I have a huge collection of vintage vinyl. I did concentrate my collecting to first releases of recordings in the fields of Jazz, Blues and some classical chamber music. I did collect with a general interest into a diverse range of interprets in different fields of practice. Just to give some examples, I did collect saxophone performed music and did try to complete the original recordings (only EP and LP) from the most well known musicians of this genre. So I got a range from Coleman Hawkins to Archie Shepp, from 1948 to today with 30 and more records of lets say the 20 best saxophone players of all time each. Next to a whole lot of dedicated jazz music as well with female voices, I did collect music with Cello as main instrumentation. (No wonder cello, sax and human voices cover the same tonal range) So I got the Pablo Casals work complete and continued to collect over lots of other interprets like Jaqueline du Pré to Sol Garbetta today. Just this three genres might explain how I do collect music. So it came that I got a still quite small collection of vintage vinyl, maybe 1500 records, but with the most of them of exceptional rareness. As stated in the earlier articles, I was driven from the believe, that only the first pressing will contain the "richest" and most complete transcript of the original recording. And sometimes when I had some later pressing before I found the first release, I could confirm my believe.

Variety of first releases of "Miles Davis - Kind of Blue" in mono and stereo, a exceptional example where the first pressing is a incredible lot better comparing any later reissue, even the the 50th anniversary edition from 2009 of the most important jazz album of the 20th century.

The captured quality between first and later releases hardly depend on the handling of recording companies with their masterings for later planned reissues. Some of them did store the original master away as some sort of untouched back up and others made copies for their further use. This practice will degrade every later release with a typical increase of dynamic attitudes normal with every reproduction step. Others seem have handled this question different, Verve for example seemed to be a company where even later releases are able to store the same quality known from their first pressings. Some companies had better or sometimes even lower quality levels within vinyl production, several companies have been sold during a quite short time. So the production parameters changed a lot permanently. Another aspect is the distribution aspect of the first released records worldwide. So the most recordings have distributed foreign cousins of the same time. RCA for example did held for the German market a joint venture with Teldec, a german vinyl production brand from Telefunken and Decca, another european joint venture. As we see there was a lot of money in these days markets and like always, when profit attracts analysts, quality is not anymore the foremost argument. Was it ever?

Vinyl is rich. ...and tasty!

Today the most of a younger generation have audio playback reduced to smartphones for storage and don't see arguments for specialized audio hardware anymore. The basis to such handling are compressed audio files, a development made possible by the invention of the Fraunhofer algorithm for MP3 compression. In 1982 this compression standard was invented there, right two years before Phillips/Sony introduced the Compact Disc as a second digital format (after crash with the laser disc). With the invention of compression the digital distribution of audio technology started its crusade through all media components.
In the former separated audio world the first arguments for the compression have been found in the necessary reduction for the increased bandwidth of 5.1 surround sound audio – do you remember? Creativity in capitalism is never forced to find better qualities for the same amount of money, rule is to find almost the same quality for half the production price as only effective argument. Staircase to hell...
So it made possible that you might be able to carry my whole vinyl library of 1500 vinyl recordings and the additional 500 CDs at my smartphone, just compressed to MP3 standard? – Progress. Yes for the markets …

When operated within high quality audio components it is clearly audible that a and in particular a higher compression of MP3 shrinks out almost any fine and micro dynamic content and reduces the remnant to a rough torso of soulless blunt music images. The compression rate defines how much micro detail will be captured in order to find space for storage. Within high resoluting audio components the later invented algorithm of "lossless"-compression is the only acceptable audio format to capture the audible content of the original "red book"-standard known from CD.
Since the turn of the century "higher resolution" digital formats (96kHz/24bit) have become standard within any sort of audio distribution. So all recordings have been made nowadays with this new industry standard. But as well all mixing, shaping and mastering happens completely in digital form. This has a tremendous impact to the finalized and kept quality, since almost all interventions happen without trace. All the former well noticeable "fingerprints" in analog productions left from each step of and each component is rejected for a general highly refined audible result. For a lot of people this progression into refinement, better phase correction and a truly better balanced and wider sound stage, will be called "analytical"or "artificial" and are connoted to them as "digital sound".
As already stated in my last article, I do appreciate the extra apparent nivelling attitudes of modern digital recordings made within the last decade. Here the general difference between a poor and a well made digital recording hardly can be assumed as a 10% tolerance, where analog vinyl can be proud to capture 50% tolerances at its best. Some people call it "rich and colorful". For me and my vintage record collection it is getting harder and harder to accept both features as positive arguments when comparing vinyl with modern digital records. The most vintage records are not really easy to listen to, they create a high degree of attention with sometimes sparkling energies and superficial dynamics, mostly a bundle of overwhelming attracting attributes. The modern digital recordings at the other side give me more chance to get into the music flow and let me forget about the electronics equipment involved.

Conclusion

End of November I went to a life concert of Cassandra Wilson. When I booked the tickets I had several values with different price tag. I needed three tickets and wondered that very close to the stage at the right side three related seat were bookable. At the performance I realized that just in 90° angle to the stage the view was very close and fantastic with 8 meters distance, but the sound was really terrible poor. All speaker columns where installed high above the stage with direction to the main hall, in my position only the stage monitors have been audible and the reflecting sound from the opposite walls, ending in a really vague, queasy and inaccurate sound. My friend and I agreed about the perfect view of the event, but the sound was amazingly better known from home with a good audio set up. So finally I was happy to capture a colorful live image of her to be assembled with better sound at home. Apart from that I did find curious that a world class singer performs today almost a complete set of songs from an album released 22 years before in 1992, "Blue light 'til dawn" her first album with Blue Note. This album did exist for almost twenty years only as CD release, the vinyl version is quite actual. As I said earlier I did buy vinyl albums believing that the vinyl is richer and better in every respect, since I did own the CD for almost twenty years. Everybody who knows this album, knows it is a really well made recording, with perfect dynamics and well resulted harmonics and perfect micro detailing, in a way exceptional for its time.
Writing at these articles and infected from the poor life event sound, I did pull out my vinyl record and my digital version of that album in order to make some comparison. I did take perfect care about both loudness levels to be perfectly identical. Before I was absolutely sure that vinyl will be more dynamic and the digital version might show up with better resolution of mids? I did try the test for a whole side of the vinyl record, perfectly pitched into the same groove/track.
I did switch from one source than to the other, I did switch back, –  again and again. I could not believe what I did hear. It was absolutely the same. Not even a small difference, after five times switching I did loose the source, what is actually playing? Platine Verdier with SME 3012 and SPU or the streamed digital file using WiFi into my preamp? Nothing no difference at all. Exactly the same. I was completely irritated. AAD, analog recording, analog mixing and digital release vs. AAA with analog release as a vinyl record. Believing and blindtest, – religion and reality…

Remarkable test, if I would not have made it myself, I would not believe the results. For somebody like me, some would name me a hardcore quality enthusiast and refusal of the common "self-healing power of the market"- believe, it was a dry lesson. My understanding of audible perfection is grounded to experiences where older means mostly means better in general, deeper involved, longer lasting in terms of functionality and superior sounding in any audible aspect. When clearly today the first generation of speakers, horns and drivers made by Western Electric Co. in the 1930ties are able to outperform any following product in history in almost any term, such is a basic experience. If almost any audio product designed and engineered for professional use in the broadcast industry, betters any commercial made mass product for audio, it shows another side of the same coin. If product history of original superior products show a permanent decline in quality terms into mediocracy with every released product generation, i.e. like with products from Altec or Tannoy, it shows another problem of the tensile forces with common markets as third argument. Than it is difficult to accept that a solely commercial made product like the digital audio file will be on par or even superior to its analog predecessor, the analog master with the vinyl record. But was a vinyl record ever something different than a commercial placed product for consumers?


I would be happy to learn about other peoples experiences with that topic,
Volker

Natural vs. Analogue vs. Digital vs. Fraunhofer Algorithm processed Music III

Hello to everybody,

interested to follow on. In my last article I did end describing that my believe into the superiority of analog audio reproduction has had almost religious qualities, based on a deep believe, breaded by several "audio mullahs" of the orthodox conservative brotherhood of vinyl junkies.
I did believe for almost my whole life within audio components, that analog play back is superior to any digital technology. I spend 25 years of faithfulness, energy, money to find that believe confirmed by complex evaluations. To be honest, even with substantial input into my system (I did ignore for 15 years any digital source) I never reached a stage of perfection, where I would subscribe with real empiric experience this sort of "religious confirmation". I did always buy the vinyl record if there was any, even when I already had the CD. My long term experience from the early 1990 years with digital music had shown me a poor source, when evaluated with higher degrees of audio program. The mistake once I did made with this score can be cleared up today. The digital program material was mainly based to analog recorded, mixed and mastered material transcribed to CD. Music which had already all the fingerprints typically imprinted from loads of analog components within their production, but with a additional stage of influence, the remastering for digital, cannot sound any better than its original. Every step of reproduction leaves a clear finger print, but in these days digital stored music was the "jack of all trades", able to solve unknown problems – in theory.

It took a long time that my music taste changed to more contemporary performed music of younger generation musicians. Together with my interest to manage my small digital self recorded music library  from my computer, I started in 2005 to play music from there using an audio interface. It didn't take long, that I worked out that my "old school dac" (Meridian 263) did a good job to convert the digital stream into analog audio signals, a lot better than my interface was able to. And in detail after several evaluations with modern "high resolution" dacs, it showed up with the old truth that mainly the analog output stage converters make a audible difference, in particular with following tube preamplifiers and the their input impedance preferences. But as well a solid designed audio output stage made with single coupled transistors, or even better with tubes, bring the dramatic dynamic changes into view, it is not the dac topology in general. The always as standard implemented op-amps here for the analog amplification stage is the foremost achilles' heel and dramatically reduce the finalized output quality.

The album was Archie Shepp's On Green Dolphin Street, became the first digitally-recorded album in the history of jazz music  was made by Denon.

During experiences with my own digital recordings and first results with audio software for a computer based audio workflow from 2005 on, brought out several findings about digital influences to the final result. Different resolution options and compression settings showed me their inherent limiting issues, together with the effects of variated word length rates, the influence of general sampling rates higher than 44,1 kHz up into actual regions of 192 kHz have been tested for superiority.
To me the so called "high resolution"-audio formats (96, 192, 384 or more kHz with 16, 32, 64 and more bits word length), mainly introduced as argument to find new selling options within a shrinking market of downloaded or streamed music formats, are in a high resolution audio chain of completely negligible importance for the quality of audio performance (believing trust). While any sort of digitally introduced compression algorithm is clearly accompanied with a precisely defined loss of micro information, phasing, spacing and dynamic ability. I do not know one audio system where such values are able to determine audible qualities of any importance!
In the age of component less music consumption, relying to the smartphones as universal remote control for any question of todays life and here more or less as converting unit into the analog music signal, another belief takes ground, the religion of zero and one always to be the same figures...

When I started to transcribe my own vinyl collection into digital, it was supported from the believe to preserve the better i.e. "richer" sound of analog vinyl on to digital. I tried with different methods and recording hardware (in "old school"-terms hardware has had always a tremendous influence to audible sound quality, believing again) to find the best possible sound quality for my recordings. So I did use the first Philips/Marantz professional CD-recorder (Marantz CDR600 with the built in legendary first laser burning mechanism with a unsurpassed burning depths for long term archival storage at golden CD-Rs Philips made). I did try with professional DAT tape recorders as well, as I did do HD- recording with stand alone machines and finally I did use my computer with audio interfaces and software to optimize my recordings. I spend a lot of time into that research with the result, that I could not rate any recording principle as to be superior in terms of audible qualities. Only the comfort of use, the spend input of energy and time, as the ease of storage, did finally determine my decision. I even pulled out my old Meridian CD-player to try another step to use hardware for playing digital stored music, but I stayed more or less with the computer and sold all specialized hardware, a step I did explain myself to set for future demands …

I still did believe into my analog system with a Platine Verdier turntable, SME 3012 tonearm, Ortofon SPU pick up and extremely complex tube amplified phono amplifier with inductive equalization to be state of the art. Vinyl is clearly listenable to be the "richer" format, specially when it comes to typical vintage vinyl and so it stated these arguments to be highly superior. The black box of digital data generation can always be seen in contrast as some sort of "diabolic mystic conviction" and with its inherent mathematical system as a true unnatural operating generator, it can be seen as a complete opposite of the musical instrumental origin.
Further religions: US Americans need firearms for better safety, earth warming is not affected by humans, German cars are best in the world and several other ideas withstanding any serious intelligent approvable investigation are of similar significance.

Using the computer for audio storage brings several other questions into account. As photographer and graphic designer I have learned my whole life to work with Macintosh hard- and operating software to optimize analog products. A obvious decision in the first move was to use iTunes for the organization and storage of my still not really seriously taken digital music library. And there is the question of the finalized format included, several compression formats are existing, as well the newer Fraunhofer variant of Mp3, the Lossless format can be a serious option, apple supports the most of them, others don't. And what are the formats in the coming future? The hall of fame of rejected data formats and carrying hardware has grown to a football field size hall of confuse within the digital age, if you just recall 5,25'' floppy disks or optical disks of different manufacture. Today we use clouds (not me) and hard disks for storage, what will be the technology in five years time? Do we need to own our music or will it change completely to cloud streaming with flat rates? It will depend as well on our relationship to our music. Since I don't need any shuffle playing option from my library, others prefer such a undirected support of all-time background music. On the other hand, when I have stopped once playing some of my albums, I hardly find back to them, so I might not need to own them for a lifetime period.
But what when it will happen like in 1995 again, when almost all new produced music sold as vinyl format disappeared for the CD, and today the CD as medium will disappear together without any option to get the same audio standard in other form, it might be getting difficult. My digital preference for my library requires "red book standard" as minimal resolution option, any lower option is not acceptable in audible terms!

Today all recordings are made with solely digital production parameters, where almost all steps of mixing, refinement, manipulation and mastering are introduced in the digital stage. Here now the typical fingerprint of each component and part known from former analog productions is almost invisible for a all around neutrality. This effect creates a much much better general audio quality as average result, comparing it with the early 1990ties. Modern digital recordings can be compared in quality terms within a range of deviation with maximum of 10% divergence, they differ mainly in terms of captured overall dynamics and lost of micro detail, values absolutely unknown from analog vinyl productions, where the captured quality differs to my estimation for more than 50%.

Read on soon, Volker



Reference to the shown miniature speakers was a japanese web page, I was unable to decipher a name of its author, I am sorry for that. I hope the shared attention will be welcome.

Natural vs. Analogue vs. Digital vs. Fraunhofer Algorithm processed Music II

Hello to everybody,

who is interested into a discussion about audio qualities which are obtainable from different storage principles. First the analog vinyl disk, the digital disk or its equivalent of streamed data (on red book standard), the various compression algorithms versus pure naturally performed music, shows clearly the individual limitations and merits of each technology.
As I did describe at the end of my last article, I came once to a point with my own set up where I clearly could evaluate the analogue recordings as main factor of limitation. I began to understand that my record collection of vintage jazz first released vinyl was not able to give me a minimal stage of uniformed performance standard, even when some sort of cutback will be accepted as restriction. Comparing vintage vinyl with modern (past 2000) digitally produced recordings leads to a clear conclusion, – vinyl is clearly characterized with loads of "tasty extras". I would like to find out what makes the analog response so difficult to be on par with current digital produced and stored music.
With vinyl the soundstage widely differs in terms of general dynamics, tonality, space and phasing accuracy, even when the record formally recollects the international production standards of RIAA reglementation. To my personal believe every little part and component in the recording chain, as well within the mastering process and finally in the individual play back system, – each components adds a little individual fingerprint into the analog signal. At the end the finally archived sound differs widely in several parameters like phasing, dynamics, resolution, resonances and as well with its generally captured tonality.

I did try to describe in the last article that I wanted to correct the audible results with variable equalizing parameters in playback, similar to the well known curves from different manufacturers in the age of non standardized mono recordings. I did try as well to optimize the incorporated equalizing filter by different technical filter principles, closer tolerances and as well with different made parts to match different audible effects. Beside conventional RC-fiters as active or passive designs, I did try inductive variants with coils in order to get rid of the hardly beloved limiting capacitors. I did try almost any type of capacitor, like silver mica, polypro, pio, styrene, etc. As like always the oil paper caps did sound best with the poorest measured performances and by far wides tolerances, which need sensitive matching accordingly. To make a short cut to the end of my evaluations, all these different components and designs just add another finger print to the almost rich collection of sound textures within analog recordings.
I would go as far to state, that this "sort of richness" is the matter of fact for the believe that analog reproduced audio is sounding better (richer) than digital reproduced recordings.

In our audio systems the effects of individual components caries to add on each some informations to the final signal. Let us just look to the very front end, the cartridge. Everybody of us has made the experience that every cartridge will sound different in the same record player-arm combination. Even if the cartridge and the arm are perfectly suited to each other with a highly adjusted compliance and weight combination, every "arm itself will sound different" and as well every internal wirement will do so. Use three different step up transformers, you will have three different sound images and it will cary on with every following component in the chain with tremendous effects. Analog sound is a summery of some "pure signal" and loads of different fingerprints left from every component involved to the signal till speakers transduce it into individual aural waves.
Yes, analog sound is rich, may be overloaded rich, sometimes perfectly shaped, but mostly with a individual clear audible sound shape, but never neutral or uncolored. To bring it to a point, from my collection of 1000 first releases not even two records do sound perfectly identical (or some sort of neutral) when compared closely.
Yes, analog reproduced audio material is rich, richer than digital recorded, mixed and mastered program material. But does this mean that richer is automatically any better?

To my opinion it is always a good help to listen to naturally performed music. Performed without any electrical amplification and sound transducing units, just plain acoustical instrumentation. If you do so, you will realize how modest and unaffected such a performance happens and how easy natural performed music is at the ear. The most audio and hifi systems add a lot more attention gathering effects to the signal, mostly as a sign of its inherent limitations. So electrically generated loudness keeps up to compensate these limiting issues and typically show up at the same time with overexposed hardening effects and correlative phase shiftings.

In 2007 I did still believe into the superiority of analogue processed music. I did start to make recordings from my vintage vinyl. My attempts were carried from the believe that the original first released vinyl recordings do carry so much more information (richness!) in their analogue groove and in addition that a digital recording made with the support of a almost perfect record player like the Platine Verdier with 12'' tonearm and SPU cartridge, will outperform any commercial transcripted cd release of the same original recording. And indeed it came out to proceed recordings from vinyl which have captured "the richer and more attentive sound" known from the LP, now for me available as lossless format or burnt down to CD-R. "What a step" to form a own reality into the trueness of believing! Audio as religion...

Read on soon, Volker




Reference to the shown miniature speakers was a japanese web page, I was unable to decipher a name of its author, I am sorry for that. I hope the shared attention will be welcome.

Jan Vermeer, The girl with the pearl ear ring, 1665
Van Gogh, Twelve sunflowers in a vase, 1888
Van Gogh, Autoportrait with fur hat and bandaged ear, 1889

Natural vs. Analogue vs. Digital vs. Fraunhofer Algorithm processed Music I

Hello again,

after the waves of reaction in the aftermath of the Analoge Forum 2014 in Krefeld have weighed within the discussion about my last article, I took the chance to think a lot about the big differences in  individual perceptions of sound structures again. How can it be, that a certain sound evokes such different reaction by different individual people. Since many years I try to understand if a listening ability is natural born or in difference is a highly trained property, or can it be even either or?

I really do not understand that some people, even if they got used for 20 or 30 years to typical high quality audio equipment, do show such heavy differences with the evaluation of the audible profile? Even some long term compaignons with extremely similar audio components in use astonish me regulary with a completely different interpretation of the together auditioned experiences. Everybody of us might know that professional musicians with some deep and long term listening experience to real music and practice with natural instrumentations, do not share the same evaluation grading, which may be typical for the "audio aficionado". So what makes the difference?
I am not sure, but I think it is quite obvious that the musician "knows" what he hears and therefore is able to make some sort of abstraction as a short cut in his brain. The authentic real sensual impression is overridden by his educated knowledge, the most musicians I do know, can live with a tiny pocket radio as source for their favored music. They don't need any high quality audio equipment imitating wider responses of music to generate this process of abstraction of "understanding".





It might be a bit different with more or less technical orientated and experienced audio aficionados, but finally it comes to similar results. Everybody of us has clear expectations about what we do listen when we know what we are looking at? With other words, do we listen with our eyes and our brain/knowledge instead our ears? The all-time favorite blind listening test always bring out similar results, the most people are unable to resolve just by the pure listening experience, if they do not see what they know… do not know what they see…etc., it is getting difficult to evaluate.
Some other people need to close their eyes to interrupt this typical process of forming in order to improve their sensual audible receptivity.

Since I started to use tube audio equipment in the middle 1980ties the most statements of international audio "experts" seem unanimously to confirm that analog processed audio signals from vinyl record players, tape machines or tuners have a exceptional more natural audio response than the high tech sampled digital formats. Their arguments were chosen to match some of our logical understanding as being a creature of natural conditions and is to be seen in direct opposition to the implementation of digital music as a typical instrumentation of technical ideas as market mechanisms and commercial practices. It is very easy to follow such argumentation for some sort of theorem as our own understanding.
The 'experts' always did state a general unsurpassed quality of analogue formats as to deliver better separated tonalities, improved resolution, refined timing issues, better integration of harmonies, a improved coherence and by far better dynamics than digital stored music formats.  In these days of the advent of a new commercialmedia standard with the PhilipsSony-Audio CD, highly pushed into the market by heroic figures like Herbert von Karajan to create a second flush of income as a result of already existing music as vinyl format, made the whole process of digitization a quite dubious action happening in the "black box" of the new digital world.

I started in late 1980ties with my first Garrard 401/SME 3012/II and Denon DL103 with lead body together with my first tube preamp and Leak tube power amps my own audio experiences in order to explore these enrolled theoretical statements. As well I did spend a fortune in parallel for my first real CD-player, a highly praised Meridian 206 for 3500 German Marks, as to be a important investment for the coming future. To be honest, I never did like the sound of the digital player, it was always drawing a lot to much attention with its extremely detailed sound structure, but in return my analogue set didn't do any better but different… So I found myself trapped in the typical situation of the common audio aficionado, try and error was set up for the coming decades…

I took me 20 years from these early days to work hard at my deep believing into analogue processed music as a better principle with much more natural, deeper, wider, coherent and in every respect improved inner structure of music enabling it to sound in every respect superior to digital. This phrase should have been kept enough controversity to distrust such an idea as being a "egg-laying jack of all trades".
In 1998 I got finally a Platine Verdier turntable which brought me as close it can get into front of vinyl music representation (unfortunately I never had a chance to evaluate master tapes within Telefunken M10 studio tape machines). The magnet bearing player gave me a chance to support my deep conviction about the advantage of millions of more and better stored informations in the groove of the analogue vinyl disc comparing it to the industry standards of digital processed music. I never did question again the hardware again, the improvement to former decks showed me a perfect combination of the best attitudes of both worlds of record players design as a perfect synergetic example. The finesse, calm, resolution and micro dynamic harmonies only known from perfectly isolated sub chassis players on the one hand. On the other hand it merges these attitudes into the powerful, dynamic and expressive performance only known from heavy weight mass players. To my knowledge with this combination of positive effects (maybe not the right word here), it is still in its own class.

So did I send my Meridian CD player into retirement in the late 1990ties and concentrated completely into vinyl based music reproduction. I did collect when I was living in the US a good 2000 vintage first release jazz records from Riverside, Pacific, Contemporary, Verve, Pablo, Impulse, Blue Note, Atlantic, Columbia and a lot more companies released between 1955 to 1969, always believing that the first release is made from the master tape since late releases are made sometimes from transferred copies. Before I had bought lots of rereleased CDs (analogue recorded and mixed and mastered CDs) of the same genres jazz and blues, sometimes even the same records, together with a lot of classical music performed at almost the same time.

Over the 2000nd years I did spend a tremendous amount of time to improve the performance of the vinyl deemphasis within my system of tube preamplification. I did realize a whole bunch of different conceptions of preamps with completely different tube implementations (like triodes in diífferent modes, like cathode follower designs, SRPP, SE, choke and transformer coupled, as well with DHT, within active and passive standard RC or IC equalization), alway driven from the idea to find the perfect analogue music signal containing pure music.

During these trials I came across that RIAA deemphasis might not be the universal solution, since in history different record companies did implement their own deemphasis filters. I did try to improve the final reproduction stage with variable filters, in oder to compensate the always existing differences between different records and in particular between different brands. But I had to learn that the classic filter with its turning point at 1000Hz and its peaks at 500 Hz and 2120 Hz gives not enough freedom to compensate the wide spread differences pressed into records. The shaping of that filter is a very humble option to compensate these differences, there are a lot of other influences, which have a great effect to final pressed record.
Every analog component in the recording and mixing chain will leave a clear finger print in the final record. Phase shiftings in the whole bandwidth, every microphone, transformer, tube, capacitor, together with different technical principles will shape the sound of a record tremendously. Its mastering with all its components and processes, its stencil cutting and finally the pressing stamp will shape the final product of a vinyl record tremendously. And we are just talking about technology and components, which excludes the most important factor as any sort of processing, the individual influence of human individuals at any stage of the chain.

Read on soon for the next article following these issues, Volker



Reference to the shown miniature speakers was a japanese web page, I was unable to decipher a name of its author, I am sorry for that. I hope the shared attention will be welcome.

Analog Forum Krefeld 2014

english version at the end


Hallo,

nun war es wieder soweit, nachdem im Sommer in München mit der "High End" bereits mit Beharrlichkeit und lauten Beschwörungsgesten der unaufhaltsamen Sättigung des Absatzmarktes HiFi durch das audiospezialisierte Nischengewerbe entgegnet werden sollte, öffneten sich nun auch wieder die Tore des Analog Forum Krefeld 2014 für den ambitionierten Besucher. Das Analog Forum ist eine Veranstaltung der Analog Audio Association, einem Verein der schon vor langen Jahren mit dem Ziel gegründet wurde, den Artenerhalt der aussterbenden Spezies "Vinylschallplatte" mit der Nachhaltigkeit und sektiererischen Frische von Spielzeugeisenbahnherstellen und deren typischem weltoffenen und innovationsfreudigem Habitus Profit zu schlagen mit einem Forum entgegen zu wirken. Vor einigen Jahren hatte ich mich über einen längeren Zeitraum bemüht, in einem ihrer Zentralorgane, nämlich ihrem Webforum,  über den Stand der Dinge dieses Themengebiets regelmässig zu informieren und auch auszutauschen. Das habe ich dann doch ganz schnell wieder eingestellt, zu offensichtlich war es dann doch, das ein offener Austausch im Bemühen um qualitative Entwicklung zumeist von kleinkariertem "Besitzhabitusdenken"gelenkt und bestimmt wird. Nach wiederholter Erfahrungen dieses Umstands, habe ich mich dann spottend aus der Diskussion um die Qualitäten der Vinylschallplatte aus dem von mir vortan nun "Dualforum" geschimpften Plattform zurückgezogen.

Nun also sah ich es als meine Pflicht, wenigsten einmal den "Freunden der Spielzeugeisenbahn" Liebhabern aufwendig verchromter, komplex gravierter, mit umfänglich vorgegebenen Einstelloptionen für mindesten drei Tonarme versehenen (davon mindest ein 16-Zöller, am besten einpunktgelagert) und folgerichtigem dreistelligem Nettoversandgewicht ausgetatteten Analoglaufwerken (früher Plattenspieler genannt), einen Besuch abzustatten. Ich mache keinen Hehl daraus, das mir ehemalige Veranstaltungen schon solcherart suspekt allein als medial vermitteltes Ereignis erschienen, das ein Besuch für mich überhaupt nicht zur Frage stand. Das mag man für arrogant halten, aber schließlich kannte ich genug hinlänglich "Interessierte", die mich auch immer wieder darin bestätigten, einen Besuch dort nicht als "zwingend" einzustufen. Zum anderen weiss ich nur zur gut, das kommerzielle gewerblich orientierte Interessen mit meinen Erwartungen an ein hörbares Ergebnis, sagen wir es bescheiden, sich nicht wirklich zweckdienlich zueinander verhalten. Schließlich habe ich ja auch seit etwa 25 Jahren keinen HiFi-Laden mehr betreten, immer wohl wissend, das mir da "schon geholfen wird".

Nun gut, 2014 TrueFi goes Audiofair. Ich war überrascht, wieviele Menschen sich an einem Feiertag in engsten Hotelzimmern drängen, um sagen wir es salopp, eine Stereoanlage zu hören. Schnell war man in der ersten Runde durch die meisten angerichteten Räume, jeden Zweiten musste man wegen Überfüllung auf die Folgerunde vertagen. Aber auch deshalb schnell, da es unabhängig von Aufwand, Marken und Equipment eigentümlich ähnlich tönte. Man brauchte dafür kein sonderlich geübtes Ohr, das allgemeine Niveau der Aufführungen war sehr, sehr ähnlich und ich sage es vorsichtig mit Rücksichtnahme auf die HinterbliebenenAmbitionierten sehr, sehr bescheiden. In schon krass zu nennendem Kontrast zum Aufwand der dort getrieben wurde, klangen die Ergebnisse seltsam befreit von aller musikalischen Substanz. Schnell konnte man zumeist schon beim ersten Basston oder in der Grundtondarstellung vernehmen, das das Gebotene andere Ansprüche bedienen wollte, als dies meine sind. Nach selten mehr als einer Minute gesellte sich beim überwiegenden Teil der Aufführungen auch die Erfahrung eines meist sehr vordergründigen, oft auch harsch bis spitz vorgetragenes oberen Frequenzbandes dazu. Und Summa Summarum in Verbindung mit den meist auch blass und farblos vorgetragenen wichtigen Mitten, wurde das "HiFi-Soundbild" schlüssig abgerundet. Ich weiss nicht ob dies ein bewusst eingesetzter flacher, vordergründiger Sound ist, der sich besser verkaufen lässt? Jedenfalls mit Musik, derer analoger Eigenschaften und emotionaler Darbietung, hat das in den wenigsten Fällen noch nicht einmal vordergründig zu tun.
Es mag daran liegen, dass die räumlichen Bedingungen natürlich nicht optimal sind, jedoch war bei einigen Anbietern auch diesbezüglich höchster Aufwand betrieben worden, Raumakustikpanele im sechsstelligen Bereich waren aufgebaut, dazu die übermässige Fülle menschlicher Absorber. Ich vermute jedoch als eigentlichen Grund für das einhellig kraftvoll unattraktive Auftreten, starke Affinitäten zu unseren Lebensmitteln. Der überwiegende Teil der Produkte der sich so nennt, hat ja auch nichts mit Leben zu tun, – ganz im Gegenteil.

Es war schon mehr als erstaunlich, das einzig ein kleiner unauffällig vorgetragener Beitrag eines Schweizer Anbieters (wer hat's erfunden?) als einer der ganz wenigen Lichtblicke die gängige Trübe Aussicht aufzuhellen im Stande war. Mit einer Stereoanlage, die mich massgeblich an einige meiner eigenen frühen Anlagen erinnerte, mit einem modernen Thorens Subchassis-Plattenspieler, fast technisch identisch zum Klassiker TD160, hübsch und sinnvoll ergänzend kombinierten Röhren-Modul-Komponenten und einem kleinformatigem Breitbandlautsprecher, zeigte die Vorführung von Swissonor Eigenschaften, die auf keinem anderen Stand so nachvollzogen werden konnten. Feine, durchnuancierte, atmende Musikdarstellung mit einer geradezu im Vergleich bescheiden anmutenden Kette. Alle anderen scheinen gerade den umgekehrten Weg eingeschlagen zu haben, nicht kleckern, auch nicht klotzen, – rüpeln scheint die Devise. (jetzt muss eigentlich wieder meinen Klassiker zitieren, der die Parallelen im Kaufverhalten von SUV's und den jeweilig anderen Produkten als gleich benennt)

Auch Wolf von Langa's winziger dipoliger Kugellautsprecher "Sphere" ist einer der wenigen positiven Versuche das dort Gängige in Frage zu stellen und mit einem einfachen Produkt zu überantworten. Vermutlich auch das ein Versuch, seinen zurückliegenden vermutlich negativen Erfahrungen geschuldet, auf solchen Veranstaltungen mit aufwendigstem Equipment zu punkten, nun marktkonform ökonomisch anzugehen. Schade, hatte ich doch gehofft dort einen der aufwendigen DHT Verstärker von Thomas Mayer in der Vorführung zu erleben zu dürfen, leider wurden die "sphere's" mit japanischen PP-Amps angetrieben.

Bleibt zu erwähnen, das die überall allgegenwärtigen Lakritzschnecken auch nicht die emotionalen Fehlerwartungen befrieden konnten. Natürlich könnte ich nun schreiben, ich habe es immer gewusst, dass sich mein Anspruch an Musikreproduktion und deren akustischer Umsetzung mit gängigen HiFi-Komponenten nicht befriedigen lässt. Natürlich könnte ich jetzt schreiben, das der organisierte Unfug auf einem Laufwerk 18 verschieden bestückte Tonarmrohre "on the fly"im Wechsel unterschiedliche Abtaster hörbar machen soll, schon mit einem einzigen Einpunkttonarm, schon als grob fahrlässige Täuschung bewertet werden muss, oder kennt jemand ein einpunktgelagerten Tonarm in einer wirklich funktionieren Kette, – wohl kaum? Nein, diese Liste der Schmähungen kommerzieller Exzesse in Krefeld will ich nicht führen, mir geht es um Wichtigeres.
Aber die Problematik geht ja doch noch etwas tiefer, – muss man seine eigenen Ansprüche im Angesicht dieser präsenten Durchschnittlichkeit, aber auch ihre unverfroren selbstherrlichen Vermarktungspraktiken wirklich in Frage stellen? Ich weiss es nicht, schlussendlich ist dieser Konflikt auch der Grund warum ich diesen Blog gegründet habe und dazu benutze ein Forum für ähnlich denkendende und handelnde Menschen mit komplett anders gearteter Erwartungshaltung zu erreichen.

So verliessen wir einigermassen irritiert die sehr gut besuchte Veranstaltung, verzichteten auf den Kaffee im Mercure-Hotel und tranken diesen dann lieber als kurzen Zwischenstopp auf dem Heimweg bei Mike. Dort wurde der kleinen Gruppe mehr als augenfällig in Erinnerung gebracht, worum es uns allen eigentlich geht. Gute Musik und deren Wesen zu transportieren, ihre inneren Emotionen, ihre Ausdrucksfähigkeiten und Spannungsbögen ohne vordergründige Technikwahrnehmung vermittelt zu bekommen. In einem Kontrast, der grösser nicht sein konnte, gelang dies mit Mikes Anlage im Nachvollzug dieses kurzweiligen November Nachmittags. Das Wetter war eigentlich sogut, dass es die Jahreszeit hat vergessen lassen. Einzig die spätere Erfahrung und Vorführung von Mikes Setup, diesmal mit Tungar PSU für die LM-Treiber, war einerseits mit ihrer saisontypischen Vorweihnachtbeleuchtung der Tungarröhren auch Anlass sich der Jahreszeit zu vergegenwärtigen. Die Performance dieser Anlage muss ich an dieser Stellen nicht mehr hinlänglich beschreiben, mit dem gängigen Vergleich der "Welten, die sich da auftun", ist der Unterschied zum kommerziellen Gestöpsel in Krefeld so unzutreffend beschrieben, das mein Bemühen dafür noch die richtigen Begriffe zu finden, auch die Unmöglichkeit beschreibt, auditive Musikdarstellung in Worten zu fassen.


Bis bald, Volker




english version:

Now it happened again, after the summer with the Munich-High End-Fair, already the inexorable decline of the audio specialized niche industry should have been countered with perseverance and loud summoning gestures, now Analog Forum Krefeld  2014 opened again the gates for the ambitious visitors. The Analog Forum is an event of Analog Audio Association, a club that was many years ago founded with the goal of typical preservation of the endangered species "vinyl record" with the sustainability and sectarian freshness of toy train manufacturers and their typical cosmopolitan and innovation-habit to profit to counteract with a forum. Some years ago I did try to inform regularly and exchange about the state of things of this subject area, in one of its central organs, namely their web forum  I did stop quite quickly, it was too obvious that a an open exchange mostly was directed and determined by a "possession habit of thinking". After repeating experiences of this fact, I decided to withdraw me from the debate about the qualities of vinyl records from what I henceforth did call "Dual Forum".

So now I saw it as my duty, at least once the "Friends of toy train" lovers consuming chrome, complex engraved provided with circumferentially set options for at least three different tonearms (including minimum one 16-inch model, at best with point bearing) and consequent three-digit net shipping weights, equipped analog decks (earlier called phonograph) to pay a visit. I make no bones about it, before the times of such events already appeared suspicious, such a visit did never stand for me to question. That may grow arrogant, but eventually I knew enough "interested", which also repeatedly confirmed that a visit is not "mandatory" for life. Secondly, I know very well the relations between commercial business-oriented interests to my expectations of an audible result, we say it modestly, are not really useful relate to each other. Finally, I have also missed to enter for about 25 years any hi-fi shop anymore, always knowing that they were no helps for me since.

Well, in 2014 TrueFi goes Audio Fair. I was surprised how many people are crowded on a holiday in closest hotel rooms, to say it bluntly, to hear a stereo set. Quickly the first round was done by leaving out every second room because of overcrowding for the following second round. But also rapidly because it sounded strangely similar regardless of expense, brands and equipment. It requires not a very trained ear, the general level of the performances was very, very similar and I will say it with careful consideration of the survivor's very ambitious with modesty. In pretty wicked to call contrast to the effort driven there, the results sounded strangely exempt from all musical substance. Quick one could usually hear with the very first bass note or in the lower frequency representation, what is offered would serve other claims than mine. After rarely more than a minute, the experience of a usually very superficial, often harshly pointed to rendered upper frequency band joined them in the majority of the performances. And summarized in combination with the usually pale and colorless middle frequencies, the typical "high fidelity sound"was presented conclusively. I do not know, if this is the typical deliberately shallow, superficial hi-fi sound is, that it needs to sell? In any event, with music which features analog and emotional content in a foremost performance, the shown attitudes do not even represent superficially this values in most of the cases.
It may be fact that the spatial conditions of course are not optimal in hotel rooms, however, for some providers the highest rate of respect has been operated into room acoustic, panels in the six figures rate were constructed. However, I suspect as the real reason for the unanimous powerfully unattractive appearance shows strong affinities to our food. The majority of the products of the so called, has also nothing to do with life - quite the contrary.

It was more than amazing, that a small inconspicuous adduced post from a Swiss manufacturer was one of the very few bright spots, able to lighten the common turbidity view. With a stereo set, which reminded me to some of my own early systems, with a modern Thorens subchassis turntable, almost technically identical to the classic TD160, pretty nice and useful supplemented with a modular tube  amp component system and performed with a small-sized duplex speaker, the demonstration of Swissonor showed properties, that could not be tracked in any other state such. Refined, nuanced and breathing music notation with a downright modest compared sounding chain. Everyone else seems to have just taken the opposite path, sheer mass and glossy surfaces seems the motto. (now it would be time for my classic quote, that names the parallels in the purchasing behavior of SUV-cars and the respective products other than actually equal again)

Even Wolf of Langa's tiny dipole ball speaker "sphere" is one of the few positive tests to bring the major offers there into question and to respond with a simple product. Probably also an attempt, presumably his past negative experiences due to score at such events with lashivly equipment, now with the market to address economically. Too bad, I had hoped to be able to experience one of the most elaborate DHT amplifiers from designer Thomas Mayer in the demonstration there, unfortunately the "sphere's" were presented with japanese  PP amps.

It remains to mention the ubiquitous licorice snails  everywhere also could not pacify the emotional fault maintenance. Of course I could write, I've always did know, that my claim to music reproduction and its implementation with standard commercial hi-fi components can not satisfy my requirements. Of course, I could now write that the organized mischief of 18 different stacked tonearm wands to be changed "on the fly" to make different pickups audible, even with a single one point bearing tonearm might be a project of predicted failure, or does somebody know a one point bearing tonearm in a chain really work, - hardly? No, this list of insulting commercial excesses in Krefeld I do not want to lead forward, I am concerned with more important things.

But the problem is indeed still something deeper - you have to make own claims in the face of this mediocrity, but also to question their unabashedly brazen commercial marketing practices really? I do not know, ultimately this conflict was also the reason for me to start this blog and to found a forum for similar thinking people with completely different type of expectation about audio to achieve.

So we left somewhat irritated the very well-attended event, gave up the coffee in the Mercure Hotel and then made a stop over at Mikes house on the way back home to have it there. There, the small group was brought over evident in memory, what it all comes to us actually. To transport good music and its essence to convey, without superficial perception of technology to take care to their inner emotions, their expression skills and suspense. In contrast, the greater could not be, this was achieved with Mike's investment in the enactment of this entertaining November afternoon. The weather was actually so nice that it has the season to forget. Only the subsequent experience and demonstration of Mike's setup, this time with Tungar PSU for the LM-driver, one hand, with their typical seasonal before Christmas light the tungar tubes gave an opportunity to recall the season. The performance of the system I need no longer sufficiently to describe here, with the usual comparison of the "worlds that open up there," the difference from the commercial clatter in Krefeld is described as inaccurate, that my endeavors to ensure even the right words see, also describes the impossibility to describe auditory representation of music with written words.


Read on soon, Volker

The Aa Line Preamplifier IV – The Power Supply Part I

Hello,

to everybody. Today I will continue the series about the Aa-DHT-Preamplifier, I assume some people are waiting for the completion of the series. In late summer I did use the good weather to concentrate on other topics than audio, I did start a new blog with a totally different topic, so the work at the preamplifier did stick a bit. Everybody might understand without real pressure the continuing is low since I do use a almost the same preamp for a longer time already. But we will see if this "final" version is able to preserve new experiences.

The same Hamond enclosure like the line amplifier, painted with the same hammer tone silver painting. Lots of wholes  and cut outs were necessary for the quite complex power supply .

I did use the same steel case from Hamond like with the line stage for this power supply. If it would be just a PSU to feed for the line stage stand alone, the expenditure would be very comprehensible. A classic anode supply with rectifier tube and a charging and filtering chain of capacitors made up with the choke would do the job already perfect, since the design of the line preamp is completely class a. But the filaments of the directly heated triodes need to get a well made supply each, since their sensitivity for hum and other unwanted restrictions is a lot higher, than with any indirect heated tube. As already shown in the preamp descriptions I do use for that reason Rod Colemans constant current supply boards. These need each a own raw supply made up from separate secondary windings of a transformer, able to supply quite solid currents, here with two Aa in parallel we talk about 1 ampere each side. Conservativly spoken the transformer should be able to deliver a good 1.5 amperes for safety, noise and long term operation. To work out the final 3.8 volts at the cathodes of the Aa tubes a 12 volt transformer will be a good choice. It has to be determined exactly, otherwise higher voltages need to be burnt down and will create unwanted heat in the enclosure. In the first stage a typical rectification stage is necessary. I will use four 1N5822 fast recovery diodes for that job and low esr capacitors for the filter chain and  dropping resistors per channel to feed the boards.

But with the additional planned phono amplifier I need a more complex power supply. Since this second preamplifier will be realized with indirectly heated tubes, a higher degree of complexity for the anode supply is necessary, but in reverse with such tubes the filament supply will be quite easy to be realised. So my anode supply will divide behind the first filtering cap for a second rail with additional choke and a tube regulated output stage. Here a the integrated tubes of the ECL82/84/85 line (combined driver and power tube in one glass envelope) together with a 90C1 as stabilizing device are a smallest possible physical design for such a stage. This stage needs to supply less than 20 mA of regulated current output. The tube sockets and a extra capacitors are already installed for this later needed output stage.

In order to keep the grounding issues under control I did made a perspex board where all capacitors are mounted off the chassis and can be separatly grounded to avoid hum loops. I did expect to have a quite complex switching schematic, so I will install two separate switches for the different heater modes and anode voltages for both amplifier parts indicated with lamps.

MoD Parmeko mains transformer with typical sealed oil isolated enclosure and porcelain contacts.

Since the middle of the 1990's I did collect at ebay parts for tube amplifiers, which were almost impossible to find before without the web as source. The perfectly made Parmeko transformers are one example of these rare and obsolete parts for the use within tube  amplified devices. With c-core laminations and oil filled sealed enclosures, porcelain isolated contacts and very conservative ratings, these transformers belong to the best made ones in history. The most of them are made for the British MoD (Ministry of Defense) and were used at professional or military equipment and there is nothing comparable made known from any other country. Even with Ebay it is not very easy to find the right values and specifications for all projects in mind, so it took several years to collect this set which is now used for this power supply. A mains transformer with a good variety of anode voltages (300-270-250-0-250-270-300V), a perfect rectifier filament winding with 4-5-6.3V and separate 6.3V filament windings is a very good choice. The two chokes with 30H and 50H are a perfect match for both anode supplies. Only the filament transformer for the Aa's is a modern torodial design.
With this mains transformer I can use rectifier tubes with 4 volts filament, this means I can use AZ1 or AZ11/12 which are easy and quite cheap to obtain even todays where the most rectifier tubes have skyrocketed their prices. There are some early types which are equipped with mesh plates, a sound wise perfect value for such a project with low current drawing figures.

Read on soon about the next part, Volker

La Platine Verdier – The Final Turntable

Hello to everybody,

after a long period of absence I did plan to restart this blog with another Aa-preamp part to be the next entry. The Power supply should be topic shown soon, but another case of death needs to be covered first – Jean Constant Verdier, the ingenious mind of the legendary magnet bearing turntable has died recently.

Talking today in 2014 about turntables has the same attitude than talking about car design. Both issues in terms of technical inventive creativity have disappeared, instead a solely ostentatious understanding of design issues hat taken place in both fields. The bespoken record player appeared in 1980 as one of the last great innovative designs at the audio market, first seen at Maison de L'Audiophile in Paris, France. "La Platine Verdier" offered several new design issues at the first time for record players, when it entered a almost saturated market, dominated from typical japanese mass production decks, mainly introduced as direct driven designs. Only a few other sub chassis designs had survived beside them, mostly light weight built, like the Thorens and several derivated like the Linn LP12 and others. The Verdier came out with a hefty mass of almost 50 kg with a completely new concept to find the best possible options for vinyl operated audio. Here it has to be named with reuse of 12 inch studio tonearms, low compliance cartridges and incorporating first a high mass platter, it did set the path for the current audiophile record player. It was designed to resemble the mass of the record cutting process platter to catch up the circumstances during the pick up process. Next a extremely solid (20 mm) sized axis with massive bearing housing was introduced as a controlled resistive element. But the main novelty of the whole design was the magnet decoupling mechanism, which kept the platter off resonances. In combination with a spring-air controlled pneumatic acting feet system for additional decoupling of the artificial stone base down to 3 hz, the separation of the motor unit into a own chassis and a very long and thin string, the Verdier  has set the pace in terms of suspension, decoupling and weight for a mass players. All features together opened a whole bunch of aural attitudes, which have not been archived before, nor they have been completely captured up by any later design.

As simple as it can be, clearly visible the two magnet housings and the 7mm air gap in-between.

Today it seem to exist strange relationships in the purchasing behavior of SUV-cars and between  turntables. Where attitude tops function, conspicuousness resembles modesty, their shear weight and size will do some job? Todays formal principles of chromed or gold plated surfaces for drilling rigg like designs, seem to have overtaken any functional issues for more gestural attitudes with representative character.
In opposition the Verdier turntable is a masterpiece of functionality, simplicity and material choices as perfect example of the "form follows function" theory of the early 20th century modernity. For lots of people it is ugly, but for some aestetical educated, it is may be the most beautiful design ever made, since it does not show any subtile compromise to more decorative ideas. Only the motor unit could have been designed a little better for the same basic understanding.
The so called "magnet bearing", which is technically seen the wrong designation, gives this player a unsurpassed bundle of aural attitudes. First there is the unexcited calm, which gives a unsurpassed view into the rhythmic performance and a precisely defined soundstage. The naturalness of dynamic abilities, timing and the finest resolution of micro details are bundled together like none. If you own this record player, you don't think anymore about other options, – it is just boring.

Here with Shindo Mersault Tonearm and dedicated cartridge mounted on top of bronze base with pneumatic cueing system. 

The Verdier will be definitely my last record player to cover my record collection (since 20 years), for the coming future it needs anyway other concepts to play digital stored music.

Thank you so much Jean Constant.

Try to get one since it is still possible, you never know what is coming next.

Read on soon, Volker

The Aa Line Preamplifier III – The Completion of the Amplifier Part

Hello to everybody,

today I want to show the completion of my amplifier chassis with the constant current filament regulator boards. As already stated I did use the predecessor of this preamp for several years with different battery types, since conventional dc regulation showed a lot of problems and did not sound as good as batteries. So I had to struggle instead with contact problems, broken cables and dying batteries for years, which was a real pain. I had started with lead batteries, later did I use conventional AA Nimh's, a pack of three makes 1.5 hours of listening possible. So did use several packs, the everyday use and charge cycles made life for them short, almost every year I had to exchange the most packs.
In 2010 I did learn about Rod Colemans Constant Current regulator boards, which have been designed for this particular dedication, the filament supply of DHTs and for the use in pre amplification stages as special option. These boards can be configured for almost any triode type, even the big ones like 211, GM70 or 845 with high current draw figures can be used. For each triode one board is needed separately, which means here in this case with two Aa's running in parallel mode as couple will be fed by one regulator. They don't run very hot, so they are quite easy to use in the amplifier enclosures.

The Coleman regulator boards are mounted to both chassis sides to dissipate the heat and to be very close to the filaments of both Aa couples, here shown with one board.

The regulators are dead quiet and don't show any deterioration of the sound structure, comparing them to batteries. They will be available though Rod Colemans web page and are a great help for everybody using directly heated triodes in audio amplifying devices. They need to be implanted with a raw power supply each, which should be designed to match the final preferences set by the tubes itself. Any extra power will be burnt down into heat by the regulators itself. As example for the Aa with 3.8 volts for their filament a transformer with separate windings for each raw supply with minimum 11 volts output is needed. Each Aa draws 0.5 ampere of current, together it is 1.0. The boards allow the exact setting of the current to match the variations of such old vintage tubes.

Since the Daven attenuators  are extremely difficult to find nowdays, which means it is almost impossible to find them as stacked stereo units in values like 100K or 250K, I did use one mono type for each channel. With everyday use of such a preamp, separated attenuators for each chanel would drive me crazy. With any control of volume you need to match the stereo balance again, a night mare if the amp is not positioned exactly in the middle of the speakers. In order to make the use more comfortable, I introduced a coupling system. With a o-ring both shafts are coupled together by wheels from a toy steam engine. The o-ring keeps both attenuators in balanced mode since I need to adjust one of them. If, I can hold one since I turn the other one where need. We will see if that system will do comfortable within everyday use, otherwise I have to design a spring supported clutch system…

O-ring coupled shafts for the Daven attenuators.

The back shows several sockets for different dedication. From left there is the power input socket (6 pole) where both raw voltages for the Coleman regulator boards will be supplied. The other two contacts are for the filtered anode supply. Next to this socket are two output xlr-sockets, the two main output terminals of the amplifier, these can be switches for the two corresponding rca sockets as alternative outputs at the other end of the back panel. All paired rca sockets in-between are four different input contacts, which are connected to the source switch, operated from the front panel. Four inputs should be enough nowadays, since the most sources are fed through one dac, like web radio, streaming clients, computers and similar. So there are three inputs for other sources like phono equalizer or a recording unit and here the second set of output sockets will be helpful.

After mounting the two potted chokes on top of the amplifier case and after connecting the tube sockets with four Aa tubes, the amplifier chassis is complete and is waiting for its complex dedicated power supply. When the power supply is completed and will work with the dedicated smooth anode supply of 200 volts and the two raw supplies for the regulator boards, I need to adjust these with a dummy load instead of the real tubes to prevent an overload of their filaments. But till there is quite a long way… As almost everybody knows, a good power supply is by far more complicated than the amplifier part. I will show it with an option of two different versions, a quite simple tube rectified supply with the three different voltages to keep this preamp a simple stand alone solution.

For the aficionados the series of articles will be continued showing a quite unusual pre-amplification concept, which will have the future in mind. Similar to german broadcast preamplifiers of the 1950ties I will show the build of different stages with different amplification factors. A gain amp (+50 db), a catch-up-amp (+25db) for compensation of losses and the already shown line amp for impedance matching to the power amp.
With these modules and a dedicated power supply almost any use in a modern audio set can be managed. For example a typical dac output stage will need roughly a amplification of +50 db, almost the same than a good phono stage before RIAA equalizing. When equipped with a input transformer with different windings and different ratio, like 1:10 or 1:25 (just to mention the extremes), the same amplification stage can be used for both sorts of applications. Since the former digital signal is now strong enough for the impedance amp (line), the phono signal needs further equalization with a RIAA filter with typical loss of -25db at a following stage. So another amplifier with +25db gain is here needed for compensation of the losses to level up for the line stage.

A multi voltage power supply will be needed for such a amplification chain. Such complexity needs to match highest standards and components, potted oil filled transformers and chokes would be first choice, but it is already difficult to find this stuff nowadays. The anode supply develops with tube rectification at the beginning, ideally made with a classic mesh anode rectifier tube lie RGN1054 or 1064 as perfect partner of the Aa tubes, to be continued with several chokes for HV and LV: 1. a well filtered B+ for the DHTs in the line stage; 2. two well filtered low dc-voltages for the Coleman Regulators; 3. a further filtered and tube regulated anode supply for the gain amps, and finally 4. a well filtered dc-supply for their filaments of all indirect heated triodes. I assume the weight, complexity and size of a well made power amp to get an idea about the case.


Read on soon,
Volker