Thursday, 21 November 2013

Sony PUA-114 Tonearm converted to 12''

Hello to everybody. My speakers are still in work, so they are not ready for the public viewing. Instead I want to show a conversion of a unknown high quality japanese 9 inch tonearm into a 12 inch version. For this conversion I did use one of the arm wands from my SME conversion kit.

I had this japanese Sony tonearm lying around for years. I did buy it once because it has a mechanism to adjust the vertical tracking angle on the fly, it can be made during the pick up process. There is a knurled round plate just under the bearing to operate a thread, which will rise the whole bearing shaft up and down. Only a few very expensive tonearms give this luxury extra as option. So, what is the idea behind such a mechanism? If you use different moving coil cartridges, each needs to be exactly mounted into its perfect position to give its best result. Perfect geometry of arm and cartridge is the one thing to reduce errors of the pick up process. But the vertical angle varies the angle of the diamond tip in the vinyl groove. This angle has some influence into the ability of the best high frequency response which is obtainable with a given angle. So a changeable angle will result in more or less a perfect position of the diamond, i.e. in a more or less better defined high frequency response of a cartridge.  All cartridges are normed for a 15° angle in relation to the record surface. So this option gives some extra opportunity for adjustment of the response of each cartridge. If a tonearm has this option it will be very easy to match a pick up into a system just by listening evaluation. The classic heavy arms from SME, Ortofon, Fidelity Research and Ikeda do not offer this option.

This extra was my basic interest when I bought this arm some 10 years ago. But I never tried it with my turntable. Since I have the conversion kit to offer, I was thinking I should try this tonearm once. But first of all it needed to be converted into a 12 inch length.
For that reason the original s-shaped 9 inch aluminum arm wand got detached. The most japanese tonearms do fix the arm wand to the bearing house with one or two screw, here it is made with two worm screws from underneath. The SME armwand has a outer diameter of 9.5mm, almost all tonearms did follow more ore less this size, only a few tonearms use thinner tubes of 8 to 9 mm size. As well here the 9.5mm did perfectly fit into the bearing house. This is milled from solid aluminum with more than 2mm material surrounding the tube fixing.
When I dissembled the bearing house, I was surprised about the built quality of this arm. A lot of japanese mass arms incorporate the two tipped bearing principle with steel tips. Here the tips are counter positioned into micro ball bearings with stainless steel end caps. These little bearings (2mm outer diameter) are precisely positioned in caves, which are milled into the center shaft. So the depths of the tips need to be fine adjusted with a tension tool. The tips itself are made from chrome plated polished steel. This mechanical principle is only found in fine crafted tonearms, other than ordinary tonearms mounted on turntables from the typical mass suppliers.

The headshell connector on the other side of the arm wand is fixed with a little screw from underneath, similar like the typical SME arms from the 1970ties, but the screw is positioned some millimeters closer to rim of the tube. This made a cut necessary to adjust the difference, which will result in a 3mm shorter arm geometry, comparing the SME 3012 size. The effective length between center of the shaft and pick up diamond is now 302mm instead of 305mm of the 3012. I think it can be lived with that loss...

Another problem might be the new heavier weight of the arm tube. So the counterweights are a bit underrated for that tube, but if necessary, it is possible to add extra weights for compensation (Sony did offer a additional weight in the 1970ties). Of course I did use the balsa inlay to damp any ringing in the tube and I did use silvered copper litz for the signal connections inside. For a propper set up it would be necessary to make a solid base, where the shaft will be clamped in and were the whole arm will be mounted to the player. If made from a round bronze bar, like used for heavy metal shaft bearings would be the ideal choice.
I did some test without this stage of perfection, just to figure out were this arm will find its ideal use. It was no surprise that it would give a extremely precise imaging of the music, comparing it with more simple designs (like the knive edge of the SME). The other side of this medal is always a bit of the lack of sheer dynamics other arms can show. This arm might improve in this discipline with a better base construction. But never less, it is a 12 inch tonearm. It has a wide stereo image and a giant depth of stage illusion, 9 inch arms don't come by. Together with its possibility of VTA adjustment on the fly, it is the perfect tonearm for people which want to evaluate several different cartridges in their system. To find something similar in terms of comfort and in this range of quality, you need to spend some more thousand dollars.

If there is somebody out there, who might have an interest into that rare tonearm, I will be open for any reasonable offer to sell it, of course without the nice bakelite headshell and the pickup.

Stay tuned, Volker

Saturday, 2 November 2013

Trio EM – Eva Kruse, Michael Wollny, Eric Schaefer – Jazz for the Next Generation

Last year in February a friend of mine asked me if I would like to come over and visit a small jazz festival in the city of Essen. He was set into interest because of his trumpet teacher, who did act with a band there and he had recommended this little jazz festival. Without being personally involved I was in the first stage a bit reserved about going there. But I got persuaded to visit and at some saturday night in February the event did take place. The concert was opened up by a very young quartett of musicians who all had found together after finishing the quite well known Folkwang Music School. They played some moderate "resumee-jazz", a bit from all directions without any real emphasis. I started already to regret being there, in particular when I realized to see another two songs of this young band.
The next band was a quintet (here my friends trumpet trainer played himself the horn) with typically well known influences from the 1970ties as some sort of rock-jazz-crossover. I never was a real fan of rock music, nor did I like this sort of typical mixture with classic jazz elements from the bop era. I noticed after the second song that my interest did fall against zero and I would have fallen asleep, if the pa would have been not so loud. My friend told me in the meanwhile, that the third band of this evening, a young trio from Berlin, has a very good reputation already and that his trumpet teacher does not only know them well, but likes their music a lot. Ok I said to myself, I hope I will survive till the end of this evening, it already had got 22:30h. A good half hour later the last act of the evening started and on stage were three young people in their end twenties setting up a classic trio with piano, contra bass and drums. When they started it did not take longer than 10 seconds for me to be back completely alive and able to immidiate that there something extremely good and very exiting new happened. There was a presence of energy with all three, which did overcome me completely. Now I did feel very well again, my feet snapped and my brain started to relax, I could enter into the mood for the first time at that day. Trio EMs music has a very intense energetic drive as a typical component. This energetic drive is a result of a deep percussive understanding of each musicians instrument. Eva Kruses bass is often setting the pace, were Eric Schaeffers percussions add rhytmic structures and Michael Wollny often turns the piano into a giant percussion instrumentation. I have never seen a pianist sitting so agile and limber at the keyboards, he is extremely nimble and shifts from explosive maneuvers into sedative passages back almost lying completly in the inside of his piano plucking the strings with his fingers and beating them with the his underarms.

A small selection of CDs from the last couple of years, but there is a lot more to find out.
This music was some of the best jazz music I have heard in my live due to the incomparable performance all three are acting. At this evening they played four or five acts and I went home completely satisfied from what I saw. I was so convinced that I would rate the trio as one of the best jazz acts for years. Immediatly it did buy all existing recordings and went to three further live acts. When I did "google" them I found out that they had been rated in 2011 as best young jazz act since 25 years by the Süddeutsche Zeitung. This is the first time in my blog that I show work released on digital media, if you are looking for contemporary music, there is no other chance. At youtube you might get a good impression about their phantastic work.

In the meanwhile Michael Wollny is a rising star in the jazz world, he brings out lots of records were he  acts together with other musicians, and it is not allways jazz, he is trying some unusual crossovers to new music and other conceptual ideas. For example the work with Heinz Sauer and Wolfgang Kühn is exceptional as well the CD shown called "Wunderkammer XXL". I think he is one of the most interesting musicians of todays music scene without any category.

Stay tuned, Volker

Friday, 1 November 2013

The motor unit part II

Hello to everybody, sorry for a long delay with this new entry but my other activities and two fairs have  catched my complete attention within the last two weeks.

Today I will extend my former article about my motor unit for the Platine Verdier turntable with a new and easier to built round housing. A friend of mine uses two Platine Verdier turntables at different appartments in very similiar set ups. He did ask me for almost a decade to get a nice looking motor housing, similiar to mine since he followed my observations about different motor concepts. He ended up all the years with stripped down Thorens TD160 record players, without tonearm as motor units for both of his set ups. Mostly jacked up with books or card board crates to level the platter height of the Platine Verdier (minimum 22 cm, which is a lot). It looked always a bit like a neglected disaster zone beside the wonderful reduced crafted materiality of the player. Recently he burnt down his Valhalla board which I had built into his Thorens some years ago.

So when he brought the Valhalla board for repair, I thought about a way to build up a nicer looking housing as a complete integrated unit. Ten years ago I had to rebuilt my housing two times from casted concrete after accident, I decided almost never to do it again. The amount of work is just to much to make it again. Since I am in the process of bending plywoods for the front loaded funnels for my new Tannoy cabinets, I thought it might be possible as well here to bend a round housing for the motor unit, but the radius is a lot smaller. So its is a lot more difficult.

With a diameter of roughly 30 cm the wood has to be bend to its physical limits. For this reason I did use bendable plywood of 4mm thickness. In its technical specification it is determined to a minimum diameter of 26 cm. But the tension in the wood at this diameter is enormous, it can be bend but it needs to be fixed extremely solid within this position to glue. So I used the same outer round cast mold, which did use for the concrete casting a decade ago. Inside this mold I did bring three exactly cut layers of 4 mm plywood into each other, so that the single layers stabilise the others just by their own tension. It needed a lot of tests to cut the exact length of each layer so, that each layer slipped nestles into the next without any air in-between and the tensions adjust the sandwich perfectly. In order to get 9 cm height I did glue 11 cm wide stripes of almost 1 m length into each other. Finally, after drying out the wood glue, I could cut the ring on the table saw to its ideal height of 9 cm.


After building the ring I needed to to make a base and a cover to form a housing. In this design I wanted to reduce the mechanical outlay and I did it without the spring suspended subchassis my unit uses. I decoupled the main center bearing from the motor resonances just throughout the materials. The bearing is solidly set into the main construction with a massive wooden support, since the motor itself is just mounted to the 4 mm plywood top cover. Inside the housing acts like a chimney for the warm air, where the valhalla board is mounted in the center. The heat radiation of the power resistors is enormous and therefore it needs a good heat transportation inside. The most of the inner cavities can and should be filled with quartz sand in order to get mass and weight into the final unit. The filling is necessary due to the housing design, which acts more or less like a guitar or violin, with all positive and negative side effects. The unit can be adjusted to find a optimal height position for the string. A guide winded from spring steel keeps the string in central position of the platter. This guide is a must, otherwise the fine mono filament string will wander off the platter immediatly!

If somebody out there is interested to get a motor unit like this, feel free to contact me. If you are physically located close to my place in Düsseldorf I would be happy to show the advantage of this motor comparing it to your dc-motor unit, which is commonly used with such record players. Feel free to arrange a listening date.

Read on soon, Volker