The Amp Garage

Golden rule number 1. Whenever working on a amp and especially a customer amp where time is money, alway double check the for the needed resistor value with your ohm meter to confirm what you think your seeing with your eyes. Over the years I have had more then a few that had the wrong color bands i...

You have failing and or bad solder connections on the tube sockets, as such is common with this amp, and I would say at least one bad plate load resistor.

And yes, these amps are a flat out pain to work on!

No.
They likely have at least a 10% tolerance to them.
As long as they are rated for 50 volts more then the B+ they may be hit with your golden.

Yes I have a idea, post a schematic please!

If your thinking of feeding two different speakers a true 1/2 of a sine wave then I think you will end up with the worlds worst case of crossover distortion . Another concern is that for any amount of speakers I think you will end up with only 1/2 of the SPL that could have otherwise been had. Along...

I can't see why a 4 amp fuse is needed. Your speaker jack should be of a shorting type when there's nothing plugged in and having a 150 ohm 7 to 10 watt across it is a good & cheap no load save the OT way to go. Your output tube plate voltage will be on the low side especially once you factor in the...

What is up with that rectifier tube used in that schematic?

Just looked back thru my pictures and original Partridge transformers should have a yellow sticker on top the says Partridge.

I have rebuilt quite a few and that’s what the original transformers look like. Those tube shields do not look original to me though. They are not the most noise free amps when turned up loud since while the wiring is beautiful some of the grounds are daisy chained . Another flaw is that the PI sect...

I don't understand going this route.
If you have the room and with how cheap wire wound ciramic's are you can near double the wattage ( for extreame longevity and stability) and still be under the cost of those.

Give me your mailing address and I will send you a few!

These simple testers only test the emission level of the tubes cathode, so as such they are fine for testing out rectifier tubes but will not tell you how well a audio tube will amplify signal level. Like testing a rectifier tube these testers in terms a audio tube will tell you only how much life i...

With the ability you have displayed in the great reserection of the chassis you should be able to make a cab for the head easy! You might check out North coast music, as they have,or had repro cabinets. No Zobel network added to the output stage for safety? It seems everything back then was rated fo...

That’s not what the first reply to your post was questioning.

You referred to a 12AX7 as a pentode when it’s not, in fact the whole large number of the 12A series of tubes ( 12ax7 av7, au7, at7 and others) are all duel triode tubes.
They can perform 2 separate amplification functions in other words.

The main difference you would find with 34s is that the output stage will clip sooner . 34s have more gain then a 6L6, and of course this also translates into a tad more touch sensitivity. This may help to float your boat or maybe not? One other thing you can try is a set of Groovetubes 6L6 tubes . ...