• 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.

829 or GU-29 audio amplifier schematics?

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I've googled for the GU-72, looks like a very powerfull HF tube. I haven't seen audio schematic for this tube, if you have some please share them with us :)
 

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Tubes4e4 said:
For those designs shown using 3E29 / 829B / QQE04-60 / YL1060 strapped as triode in this thread, some of them use real strange operation points. Hence I would suggest to double check with the traced curves, which are available here:

3E29/829B/QQE04-60/YL1060 strapped as triode

Regards,

Tom Schlangen

Tom,
I wonder if you ever saw a dissipation disparity problem when tracing the curves - wildly different currents in the two sections, resulting in overheating of one section? i seem to remember reading something about it here a long while ago.

Also, i will take this oportunity to thank you for the traced curves for EL509 with low Vg2 and G2 driven. Would you happen to have real traced triode curves as well? I am also looking forward to finding triode curves for the EL/PL508 - perhaps wishful tinking, but you seem to be the person to ask when triode curves are needed :)
 
Hi Fellows,

Picture of my 832 amp is below. I used the Audio Hobbyist design and it works quite well. I have not hooked it up to my distortion analyzer yet but it sounds exceptionally good. Very open and plenty of punch. I used some slip on connectors from a terminal block for the plate connections - from a Phoenix terminal block.

Regards,
 

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Hi Arnold,

Well, I guess most people would insulate them. But I have no kids, no pets, no spouse and my girlfriend knows better than to touch those leads, so it's probably OK. It works for me but it might not work for everyone. Safety first and it is important.

The amp sounds great and I'm quite happy with it. The 832's work quite well. The plates glow just slightly red, which is how I like it. I did not put blue LED's in the bottom. And those are Hammond 1608 OPT's.

Regards,
 
Hi,

I design and build a low power Simple 832 pp not too long ago, sound bright, open, punchy and its nothing close to sweet to me.

Just watch out for the Screen Grid current. And since the cathode for the 2 beam tetrode are common, I have no idea as of how to balance the 2 plate currents.


Cheers
 

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Hi Arnold,

Actually, the output stage is very tolorent to PS noise, I fine it sufficiently quiet from my 96db speakers with a single 330uf cap for the power stage, but more attention is required for the driver stage, and sounded lifely too. (And cheap too cool: )

I personally hear that it kills the sound if you regulate the voltage here. or pile up too much capacitors. But if your findings proove othterwise, please share your technique.:

I didn't do any measurements, but from the datasheet, it shows that this tube is highly distorted... BUT, to me, it distorted in a ear pleasing way ;)

Happy building
 
Regarding triode strapped EL509

Hi ilimzn,

Would you happen to have real traced triode curves as well? I am also looking forward to finding triode curves for the EL/PL508 - perhaps wishful tinking, but you seem to be the person to ask when triode curves are needed :)

Triode strapped EL509 curves are on top of the tracing list, indeed. Probably not this weekend, though.

Regards,

Tom
 
Re: Regarding triode strapped EL509

Tubes4e4 said:
Hi ilimzn,
Triode strapped EL509 curves are on top of the tracing list, indeed. Probably not this weekend, though.
Regards,
Tom

No hurry, as long as we all get to see them in some forseeable future :)

BTW just to be clear, my interest in EL509/519 trioded curves notwithstanding, when I wrote above about the EL/PL508, it was not a mistype. EL/PL509 liiks like a shorter EL/PL504 without the top cap, was used for vertical deflection in large screen color TVs, and has a 12W nominal plate dissipation, even though the structure inside is quite huge (about the same as a PL36 or PL500).
 
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