Oswaldsmill tube tasting 2007
Joathan Weiss organized a tube tasting in 2007 again. A get together of audio enthusiasts mainly from the US. This time I was invited, it might have something to do with my tonearm now playing in Jonathans system.
The location as such is outstanding. Not to speak of Jonathan's cooking. The secret reason for most to come to this gathering, as rumors go. On the Oswaldsmill website there is much more information. There is a page about the Tasting from his point of view, too.
Back to Audio. Let's start with the system of the host. Jonathan's system is based mainly on RCA Equipment from the 1930ies. There is a massive 845 push pull amp driven by a AL4/300B stage, that would work as power amp alone.
The 18 cell horn driven by two RCA 1428 field coil drivers. In the subwoofer there are Altec 515s simply to replace the missing or defective original woofers. An AH! Acoustic horn again driven by a RCA 1428 is taking care of the upper midrange. The tweeter is a Fostex T825, the same type I am using with my Eurodyn by the way.
At the frontend we find a Technics SP10 or Thorens 124 in a slate plinth. The tonearm is my 12 inch tonearm. Cartridges are various, EMT, SPU, Denon, Decca. RIAA equalisation is done in German broadcast V87 tape head amps. They are modified to have the RIAA filtering of course.
But there are a lot more cool things to show.
Jeffrey Jackson, he brought his Experience Music amps (with rosewood case and black fronts, in the pic below) and also took the roll of the master of ceremony. Always starting his announcemnets with a dark voiced 'People of the mill' he scheduled the speakers and amps, gave general information and called for lunch.... Here he is working on a glass stripped copper plate GM70.
The cartridges were swapped between the EMT XSD15, the Miyabi(left in the pic above) cartridge and my Denon 103R in a wood body. The MC stepup transformers in this setup are from Dave Slagle. Extremly well shielded in several layers of mu metall and copper sheets. His theory is based on the fact that a shielding is considered infinite, as long as it is bigger than the part to be shielded, in this case the step up transformers. The speakers are Voight pipes equipped with high impedance Philips TV speakers. The sound was very airy, with good extension.
On the floor: Dave Slagle, standing: Herbert Jeschke, the man behind the Philips speaker project.
Have you seen the GM70 amps in the picture a little above? Let's feast our eyes on the wonderful tungsten glow:
The SE GM70 amp is owned by attendee Adam Israel and was bulit by Jim Dowdy - PS uses 6CM3 damper diodes into an L-filter - choke-loaded 3C24/25T front-end, copper plate GM70 parafeed output - good for about 12 Watts. (Thank You Jim for this info). This amp was also used upstairs in a system with some speakers from Doug Eisenman. These little field coil drivers were capable of a very precise and magic sound. Although all systems playing at the Mill were at a very high level, this system was favourised by most, including myself. The source was a cheap DVD player, see the blue LEDs on the window shelf...
Here the power supply of the single ended GM70 amp can be seen. Note the TV damper diodes as rectifiers. A cheap and good way to do tube rectification, just as in Michael Ulbrich's 'Boxer engine' amp, known from the European Triode Festival.
Never mind the optics and the lack of solidity of the dedicated audiophile grade 'speaker stand' or the modest looking box. Of course the physical limits did not allow a dynamic sound as it can be deliverered by horn systems, in terms of natural reproduction this setup is top notch. The center of the speaker looks pretty much like early Telefunken speakers, but they are RCAs from the 30ies. Right next to this setup there was a pair of LC1 speakers from, of course, RCA. I heard them the evening before and was also in audio heaven. They were very dynamic and forward sounding, but not as neutral and exact as the ones pictured above. You can guess the Audio Extravaganza happening that I didn't even take a picture. Funny enough that both systems, though different in character surpass, most commercial audio systems by far in terms of listening pleasure.
Another highlight for me was to meet the guys from Cogent speakers. They brought their midrange fieldcoil drivers, to be accompanied with conical horns from AH! Acoustic Horn Company.
A nice still life of AH! Horn throats, a Cogent driver, and an oreintal tea pot, or whatever it is.
After some tests with the combination of Cogent driver and AH! horn, there was setup in one of the bedrooms, which I breifly heard. The sound was very much 'there', very little colorations. Very hard to compare to other speakers I am aware of. Very nice listening experience.
One level down where the kitchen and dining room is, we find this:
The bass is a Karlson, the tweeter a cheap Eminence. But what on earth is the midrange?
The midrange horn was built from a 12" field coild woofer, cut to size with a paper mache horn and phase plug. Now that is truly DIY. The combo was driven by two amps of similar circutry, but bigger irons for the bass section. Needless to say that the sound was also very nice. Deatiled ,crisp, pinpointing, yet easy on the ear. This whole creation was made by Paul Scearce.
I am using a 300B amp based on Joseph Esmillas design. Well, it was a great pleasure to meet him in person. Not to speak of listening to his mighty fine preamp and 71A single ended amp that handled the big horns surprisingly well. No picture here, the amps were swapped so fast, but luckily all his amps are documented on Josephs web pages .
The Cogent crew: Steve Schell (left), Rich Drysdale(right), with assistance from Walter Farwell Clay (middle), pushing the main room system into glory. Once the speakers stood closer together the sound adjusted itself much more. We could hear a top level horn system playing. For example the recording of the big band battle between Count Basie and Duke Ellington. Two Big Bands at the same time, massive brass attacks. In the sound everything was there without any annoyance from high notes of the trumpets or muddled details. One Big Band is already hard to handle for a Hifi system. Here we have two of them battling in the fuirest way, and it is pure listening fun. Amazing.
Or a 45rpm record of Louis Armstrong, being played back as such a believable performance. And I thought I was not a fan of that kind of music. Learning is fun.
From left: Bill Woods and Doug Eisenman at the breakfast table.
Jonathan preparing a goat cheese omelette.
As a resume I can say that this was clearly the most intense audio fest I have ever been to.
The level of sound quality was so high in all presented systems which is really unusual. Normally there is always a system where people have at least different opinions on, or where weaknesses are pretty obvious. Even if it comes from the limited time of setup only.
Not in the mill, surprisingly every system played well. All amps were georgeuos. Wow.
Many thanks to all the participants, and of course to Jonathan for the great hospitality.
Thomas Schick, Berlin, Germany
