The Amp Garage

Okay. Thanks. Sounds like I should just leave it the way it is then.

I understand that. I understated their differences. But none of that answers this question: How do they sound different when they distort? Does one give us creamy peanut butter and the other crunchy? Does one produce greater second order harmonics than the other? Will my tone paint sound distinctly ...

I've built a number of amps using both cathodyne (always with the Paul C mod) and long-tailed pair phase inverters, but I've never built two similar amps so that I could compare the sound of the two circuits. Does anyone have any experience with this? Do they sound different when they distort? Since...

Just installed the new tubes and they biased just fine. Everything is good now. Thanks!

Okay. Forget what I said. Turns out there were several errors. Here's an updated one.

Here's the schematic, in case you're interested. I forgot to draw the FS jack and the filament fuse. There is also currently a switch to defeat the negative feedback. Not sure if I'm going to keep that feature. Other than that, I think the schematic is accurate.

Ah. I should clarify that this is NOT a Deluxe reverb. It is a scratch build that uses a DR transformer set. In this case, there is a separate 1 ohm resistor for each cathode. So, yes. Normally I would be seeing around 20 mV drop per tube (40 if the PT cathodes used a shared resistor). As I mentione...

What's TP22? Do you mean the power tube grid?

Okay, xtian. I just pulled the power tubes and measured the plate voltage @ 430V and the bias supply voltage at -49.2V. The bias voltage at the grid load resistors was -39.9V, if that matters. I have some new tubes on order.

Hey everyone! I have an amp that I built a about a year ago. It's something like a deluxe reverb with a lead channel. I haven't had any issues with it lately, but the bias is suddenly way off. Normally, I keep it set to around 20mA. Yesterday, I checked the bias because it had been a while, and it m...