The Amp Garage

350vdc would be pretty nice and clean for a quad of anything.
I have a quad of 6550's, I don't know if they like that low plate voltage though.

thanks, it "may" be my grounding method. It's my least favorite and probably most important thing to do!
I will redo my ground with twisted bus wire and make sure it has solid solder joints.

Xtian, thank you!

It was the blasted 470 ohm vs 470k tail resistor!
I had the 470k in there.

Loud and proud.

Now, what mods....

Thanks, I'll check for a mis-specced component The amp "sounds" exactly what I think...JCM800 just really quiet. The bite is there and the karrang, and the tone is very mids, nothing out of proportion... tone pots work correctly as well. B+ 430v, biased at 40v tube 4/ 37.8v tube 5, slightly out of b...

Nice!
They don't have the 1 meg pot for attenuating signals bigger than a volt.

Solved, thanks Xtian! Solution for very weak volume JCM800: Check 470 ohm PI tail resistor, you just may have put in a 470k! Original thread... New JCM800 build using old parts. Voltage looks good all around, 20v high everywhere with 125v at the wall. Master at noon and preamp at noon: The tone comi...

I'll get some clips up soon, when the house is empty : )

Hoffman has on his Tools page a listening amplifier. Looks to me like it could be made into a pedal enclosure? From the instructions it seems like it is just a series .1uf 630v and a 1 meg pot, is this correct? Then all that is needed is the shielded test probe attached to a 1/4 cable jack. Am I rig...

How about not using the doubling rectifier.
Low voltage 6l6 build?

All filament secondaries look good on no load test.
B+ is 270/270 = 540v ac, no load.

Huge transformers. Looking at the Univox U-1061 schematic it has 650v B+ at 117vac! Dorrisant B+ droppers to trim off 40-50 volts? Will that do anything meaningful with B+ this high? I received the amp "HEAVILY" modified and it did not sound too good. So I gutted it and am going to build something h...

Nearly done with it. I installed a Mid pot on the normal channel, not sure if it will stay. May need to do more to that channel if it stays, 2k, 2.7k, .68uf. Don't know yet. Problem: Symptom 1: Very light hum in the background, it goes away when the chassis is touched, nothing plugged in. Symptom 2:...

Hum fixed: Somehow a bad grid connection on V1B, pin 7 causes excessive hum. I reflowed solder on all suspect joints, some in the power section, PI and a few preamp tubes. Amp seems to sound great. Still have the hum at whisper levels...I suspect it is a grounding issue. I will install bus bar for t...

Amp is built...hum problem! All tubes pulled but, power and PI, produces 60 hz hum. Pull PI = no hum. Volume knob does not increase or decrease hum(no tubes installed in preamp anyway). With all tubes installed the amp works(vibrato and reverb work fine) but has the same 60hz hum, volume knob does n...

You aver get this fixed?

Solution you came to?