• 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.

Sophia Electric el34 mods/upgrades

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I am using a sophia electric el34 to learn about tube amps.
Does anyone out there have any helpful information?

I am trying to gather enough to put together a schematic, but certainly could use help.

I also remember coming across a simple modification that sounded interesting, but the info got lost in my last move...anyone else know about such a thing?

So far, depending on how close I can get the schematic, I will probably make capacitor upgrades, again I would be open to any community (ie: more knowledgeable) suggestions.

Thanks!
 
Thanks for the warning. I have a background in high voltage electronics and have worked with far more dangerous stuff. I will take appropriate precautions, especially since I haven't done that work for years.
The first step in caution is seeking advice from those who know better. I will avoid electrocution. A little less sure about just getting it wrong and popping a tube. Or worse, my results sounding like ****.

Would there be anything to gain by replacing other capacitors in the circuit? I am getting there with the schematic, although I am sure there will be mistakes, only the coupling caps seem to be directly in the signal path. There do seem to be some kind of unexpected filters and less than simple design.

Mostly, if I can pull off the schematic, i will understand (well, eventually) why the circuit works and what a great lesson, more than any real modifications. Then I can do a simple upgrade and listen to it while I try to build a simpler design pre-amp or something. I can't just build, I need to understand.
 
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