• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

European Triode Festival 2005

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I got back on Monday from a terrific time in Langenargen, Germany. This event was more fun than I've had out of bed in quite a few years. A brief set of impressions:

The talks were first rate. John Broskie (TubeCAD) talked about tube modeling (naturally!). He showed some excellent examples of the difference between Platonic ideals and real-world tubes. The observations about tube data sheet curves were... sobering.

John Atwood (One-Electron and Artemis) gave a nice lecture on test and measurment. He's been deeply involved in correlating measurement and listening results. His data put a lie to the idea that all amps measure the same, at any rate. Useful and deeply interesting stuff.

Morgan Jones showed a new approach to low noise power supplies with improved decoupling, using current sources feeding bypass caps to achieve low noise and high isolation. Very novel, and his relaxed pedagogical style would be very familiar to anyone who has read his wonderful books. Why didn't I have lecturers like this when I was in University?

Per Lundahl opened the kimono and showed exactly how his excellent transformers are constructed. A very witty and dry sense of humor! His quiet and straightforward demeanor was explained nicely by the observation, "He doesn't do the majority of his business with audiophiles."

The phono preamp shootout compared a veritable zoo of preamp designs in a blindish format. Level matching was, sadly, non-existent, making real comparison difficult, but what a nice effort! The "Li'l Sis" was nearly the overall winner, remarkable for something the size of a pack of cigarettes. Some clever packaging! A lot of thought and planning must have gone into it.

Best sound for me was Alex Kriegel's (www.ak-tubes.de) 1940's vintage German speakers using field coil magnets. It started as a good-but-flawed effort (the reproduction of Jerry Garcia's voice on "The Pizza Tapes" was maybe the best I've ever heard, but as the other instruments joined in, things got a bit confused), but with tweaking, he extracted some amazing sound from it. On the last night, we just melted while listening to a Dvorak violin concerto. Alex is a walking encyclopedia of older European tubes.

Guido Tent wins "Tallest Participant" honors.

Best beer was the British "Summer Lightning," served from an enormous can.

The most memorable parts were really the socializing. I filled up several pads with ideas that came out of informal conversations- I'm still in awe at the rapid torrent of great ideas that seem to flow naturally out of some of these guys. One hour with Broskie took up at least twenty pages of rapidly sketched schematics... being locked in a room with Morgan Jones was not the worst experience I've ever had. John Atwood and Allen Wright were marvelously open and patient with my stupid questions. Morgan warned Allen not to let me have a copy of his preamp book. "He'll pepper you with all sorts of niggly corrections and suggestions." Pete Millett was as sharp and common-sense in person as I would have guessed from reading the stuff in AudioXpress and his web site.

Rather than devolve into a Clark Johnsen-style gossip column ("So then, Broskie says to Atwood..."), I'll just say that my knowledge easily doubled over that weekend; similarly, my own image of how much I know probably halved.
 
Hello ,
thanks to all for the nice comments to my 60 years old speakers . This speakers are also new for me because I heard them only a few weeks before and finished the power supply one day before the ETF .
I got this speakers 12 years ago , but no information about the voltage of the field coils and so on . But some nice people here in Germany searched in their archives for articles and information from the fourties and fifties .
Here is the link to the fantastic homepage of Franck Joncheray with information about Klangfilm and other vintage german equipment .

http://klangfilm.free.fr/index.html

Regards , Alex .
 
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RE 604 said:
Hello ,
thanks to all for the nice comments to my 60 years old speakers . This speakers are also new for me because I heard them only a few weeks before and finished the power supply one day before the ETF .
I got this speakers 12 years ago , but no information about the voltage of the field coils and so on . But some nice people here in Germany searched in their archives for articles and information from the fourties and fifties .
Here is the link to the fantastic homepage of Franck Joncheray with information about Klangfilm and other vintage german equipment .

http://klangfilm.free.fr/index.html

Regards , Alex .


:)
 
Dear RE 604,

I wouldn't be offtopic, but I've got a question: what type of enclosures are you using for these old speakers?
I've got a pair of 50 years old 12" speaker, they made for movie-theatre speaker boxes. They rated 20W, their sensitivity is 97dB(!) They are in very good condition.
I thinking about to bulid a pair of horn speakers with them...
What's your opinion?

Thanks, best regards,
edl

PS.: a pic of them:
30w.jpeg
 
Edl. A wonder how the mice missed this offer. Go steady with the power rating of those 60 year old speakers........theyr'e most likely made from kellogs paper and the coils aren't made with thermal glues or any of that heat conducting stuff and won't take to solid state overloading. The power rating is probably quite low 20W and and voice coil inpedance probably 16 ohms.

richj
 
Steve Bench's preamp with separated " all passiv correction " have wrong designed time constants tau 1 and tau 2....

Upupa

You dont specify, whats wrong, no facts :(

Here is an explanation from Steve Bench:

Interesting comment but no data indicating what's wrong with them. The biggest trap everyone falls into is that the inductance value painted on the inductor is not identical with the effective inductance in the circuit nor account for leakage inductance/ resistance of the transformer driving the LR.

The LTSpice model predicts flat response with the values indicated, and the measured response agrees with the model. Interestingly the "calculated" values do not produce flat response.

And a second comment:

Remember that the LR uses positive feedback to lower output Z. This does not affect the HF pole/zeros substantially but does affect the 50Hz pole and to a much more limited degree, the 500Hz zero.

Franz
 
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