DIY 18 Watt Question.

[erock0138]

Hello all, I've just finished wiring up a Carmen Ghia Inspired amp.

The schematic: Dr Z Amps - Carmen Ghia | La Révolution Deux

I've built a few amps before and have a fair amount of experience, but I powered up as usual with my light bulb limiter, no bright glow, all voltages in spec, no concerns.

I plugged it into the mains, everything was fine, all voltages were very close within spec, but I noticed on my output jacks I get 100 VAC when standby is off. When standby is on, it drops to <1 VAC. Do you think it could be an oscillation issue? I'll try to upload pictures later of layout, but have never had this issue before. I obviously haven't hooked it up to a cabinet yet, but my scope shows what seems to be oscillation.

Thanks

[g1]

Perhaps the OT phase is reversed and you have positive instead of negative feedback?

[Enzo]

Almost like we just discussed that somewhere...

[loudthud]

The schematic you referenced does not show a ground for the output transformer secondary. It shoiuld have one, the schematic is in error. Ground the sleeve of the phone jack. You still may have to reverse the primary wires as noted above, but a ground at the speaker jack may fix it.