• 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.

Impedance matching preamp

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I don't have the guts to shove that much into a small chassis...

I built a 6L6 PP amp into a pretty small rackmount chassis thinking that "oh, it's a 2u. That should compensate for not being very deep". Never again. I'm still trying to herd my courage back together to take another crack at that thing.

That's about twice as dense... how did you get the noise floor down to a reasonable level?

Horseshoes LMAO. Contrary to most modern designs, I use the aluminum chassis is the ground like in the 1950's and the random routing of most wires cuts down on coupling. There was a slight buzz on the right channel but I shortened and rerouted the wires from the toroid to the DAC and all is well. DC heaters, too. That way the only AC is mostly away from the audio circuits.

This was also my first use of 6N14P tubes (gain).

When the volume is down, you can't hear anything from the speaker. No hiss, no buzz. Just like it should be, but even new amplifiers usually have a baseline hiss if I put my ear to the tweeter. Not here! :)

This chassis is 2" high. Roughly 1.5U.
 
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