Kitty Hawk 2 x 120Stereo Power Amp

[Greg_L]

I got one of these weirdos on the bench.

https://images.reverb.com/image/uplo...o3etgzmknc.jpg

Like the title says it's a stereo power amp. Lots of capacitors in this thing. I can't find a schematic anywhere. If any of you can track one down I'll send some good vibes your way!

[Jazz P Bass]

Whats wrong with it?
Other than those crazy power resistors and eight output tubes it should be a straightforward power amplifier.

Maybe you could get some hints from the Mesa 50 50.

[glebert]

That Reverb ad said that there was a schematic with the amp, and seller said he had two of the amps. If I were him I would have saved a picture of that schematic. You could ask him if he has it and if he would sent it to you. Worst he could say is "no" to either question.

[Greg_L]

Whats wrong with it?
Other than those crazy power resistors and eight output tubes it should be a straightforward power amplifier.

Maybe you could get some hints from the Mesa 50 50.

There's at least 40 capacitors in this thing.

What's wrong with it? Nothing, really, that I can tell so far. I just wanna know where to test. So far I'm seeing expected voltages where I'd expect to see them. It's had a few tube sockets replaced, a fuse holder replaces, but other than that it seems pretty stock as far as I can tell under all the goop and silicone. It needs new tubes real bad. One side is biased way way hot, the other seems okay with really worn out tubes.

[Jazz P Bass]

Good golly, just look at all of that residual flux.
Must have been in a hurry.
There was talk of the designers "copying" Mesa & Dumble.
I can see that in the firecracker capacitor layout.
It appears as more than one tube got smoked over the years, judging by the screen resistors.
I would test the phase inverter voltages and then the output tube voltages: plate, screen, bias, heaters and ground.
Send in a signal and monitor it at the grid to see how that looks.
Then on to the output.

[Greg_L]

Good golly, just look at all of that residual flux.
Must have been in a hurry.
There was talk of the designers "copying" Mesa & Dumble.
I can see that in the firecracker capacitor layout.
It appears as more than one tube got smoked over the years, judging by the screen resistors.
I would test the phase inverter voltages and then the output tube voltages: plate, screen, bias, heaters and ground.
Send in a signal and monitor it at the grid to see how that looks.
Then on to the output.

The voltages at the output tube sockets look to be about what they should. Unloaded plate & screen voltage around 530VDC. Steady negative voltage on the grids. Filament voltages are good and all the tubes light up. I can check all that stuff just knowing about to what to expect and where. I'm just trying to make sure it's usable. A schematic would be nice. This amp was gifted to a guy and he knows nothing about it. And neither do I. I'm just trying to get it ready to go back into service.

[glebert]

(Gets this amp as a gift): "Uh, thanks?"

[Greg_L]

(Gets this amp as a gift): "Uh, thanks?"

LOL right?

Here ya go...a rare obscure weirdo high power stereo power amp that's virtually useless in modern applications and requires about 400 dollars in tubes.

Oh...you'll also need a preamp. Source that yourself.

Enjoy!