Tube Amp Archive

ok, so now all the resistors are the correct value, and I replaced the 22k in series with the bias pot to a 15k and I now have the tubes running at about 34mV. So the only thing not quite right is the volume output, I still have to turn past 2 1/2 before I hear anything and can run with the channels...

ok so the 1% resistors are on their way. I have adjusted the bias but the max on the cathodes I can get is about 25mV. I've turned the pot as far as it can go. The amp is sounding better and louder now but I have to turn it up to 2-3 on both channel's volume pots before I hear anything. When I get t...

thanks Phil, some good info there. Looks like it's worth getting some 1% resistors. When I test the cathode the way you suggest it yields the same reading as just measuring pins 1 or 8 to the chassis. With the bias set to -35 I get cathode readings at about 10mv. Somebody on the ceriatone facebook p...

ok, so i'd say it's a 5% resistor as I got it from jaycar, I will be able to borrow a decent voltmeter in a day or 2 but until then lets say it is actually 1ohm. I have added a photo of the resistor. It's colours are brown-black-gold-gold. Would the fact that it's 5% and not 1% be enough to effect t...

ok, so right this very moment the amp is working again, the bias is back down to -41 and the cathode readings at pins 1 & 8 are 5.4 and 5.1mv. I think I just need to double check for some loose solder joints. The other things that concerns me is volume output of the amp, seems not loud enough for a ...

ok so I checked the screen resistors again and they actually were the wrong value, thanks so much for that. The cathode resistors appear to be reading closer to 2ohms with the voltmeter on the lowest setting, I am getting no reading on pins 1 & 8 of the 6l6s. I now have 470ohm resistors on the scree...

checked the wiring to both 6l6s and pin 6 on both actually read exactly the same, I must have measured it wrong originally. I have a bias pot that was turned right down so I turned it to almost half way and the bias now reads -50 but all voltages have gone up now too. There is a 1ohm resistor on the...

thanks Firestorm, using the ceriatone layout for this build with classictone transformers.
The screen resistors are 470ohm 2w (just double checked them)

Should I try a different value?

sorry, John. Will do. Hope I haven't annoyed you.

here are my voltage readings, pin 1 & pin 4 on both 6l6s seems low to me, most of everything else seems a little high, not sure about pins 2 and 7 on the v3, looks like they're half of what they're meant to be as well. v1 1.180 2.0 3.2 4.fil 5.fil 6.178 7.0 8.2 9.fil v2 1.188 2.0 3.1.3 4.fil 5.fil 6...

here are my voltage readings, pin 1 & pin 4 on both 6l6s seems low to me, most of everything else seems a little high, not sure about pins 2 and 7 on the v3, looks like they're half of what they're meant to be as well. v1 1.180 2.0 3.2 4.fil 5.fil 6.178 7.0 8.2 9.fil v2 1.188 2.0 3.1.3 4.fil 5.fil 6...

thanks ok, so I've worked out that I need to have the amp completely on, not in standby mode to get proper voltage readings. everything is reading ok now, maybe slightly high. Now the problem is that the amp has low output and slightly distorted, could be a number of things causing that. Bad tube, b...

I’ve been trying to finish the build using the ceriatone 5f6a layout using classictone transformers. I am getting very low voltage readings at all tube sockets. I have double checked that all the resistors on the board are the correct value and tested all of them. But I am still losing voltage somew...

Thanks TM, did you mean brown/white to neutral rather than black/white?

Hey guys, I know that this post is almost a year later but I'm in Australia using 240v and just got my transformers for my 5f6a build and I have a few questions about the primary wiring. You should also note, the thermal cutout has been removed from the specs For 120v the primary wires need to be wi...