Tube Amp Archive

4AR5? maybe 5AR4? Does it feel good to correct someone for a obvious and unimportant typo? I hope your day was a little better. wow! I guess spelling, grammar and logistics have no place on this forum...... cheers, It's not black and white like that. Ask yourself, does it need to be corrected to be...

In case anyone else has struggled with storing a partly used tube of silicone, my go to methods for the past few years are: Stretch a piece of electrical tape over the opening then screw the cap back on, making sure you didn't trap any air inside. Or, if you don't have electrical tape, squeeze out ...

Of course it is your amp to do with it as you want

I'm wondering if the power transformer wasn't replaced at some point based on the lumpy solder joint connecting the PT center taps to the chassis. The PT is certainly a Schumacher, and the date code is most likely ‘65 (or ‘75). So that checks out. Fenders solder grounds are usually pretty solid lea...

Ive seen bad output tubes cause that before. Also, leaky coupling caps can cause a large DC discrepancy in the bias supply, but you probably wouldn’t need to install the tubes to see it

One thing I will never do again is under-the-board wiring unless there is an access panel on the chassis (ei. Ampeg V4s, etc.), or the board is easily lifted for service. Back then, I made the decision to build it that way based purely on vanity and hubris, thinking "with meticulous planning, I won...

you can get eyelets is many different diameters and lengths. The cap datasheets will give you the dimensions you need for mounting the caps (lead dia. and pitch - which is the length between the leads). Just make sure to specify enough diameter for the eyelets to fit whatever leads you think you'll ...

Nice work!

Just musing on this, is is possible that you have a high impedance wiper on the tone or volume pots? The second triode looks like it gets its 0V bias through that path, so a high impedance wiper could be fouling things up. Maybe. What happens if you just shunt the grids, one at a time, to the groun...

Dangling in the air shows no connection to chassis. Mega hum when powered up. More of a constant hum than buzz like is the noise I'm dealing with. With power off to the unit and the jack dangling in the air, there is continuity to the OTB and no continuity to chassis. So you use your input jack as ...

The buzz does goes away when pulling first and only preamp tube. Still a very ever so slight hum in the background but that's more than likely ground related. The main noise is gone. I've only got three 6sl7 type tubes in my possession so I've got one in the preamp stage and one as the phase invert...

It sounds really buzzy to me. Do you use any dimmers for your lighting? It sounds a lot like the noise we get at the house where my band practices. The dimmers in his house radiate miserably. I know you swapped in other output tubes. But here is tip which can save you a lot of time spent chasing noi...

I'm looking for some ideas and suggestions for better lighting on my bench. Right now I have a couple of LED tube type lighting hanging over my work area and it kind of sucks. It's highly reflective off of work pieces, particularly metal amp chassis, and reflects back into my eyes. In addition to th...

I keep a bottle of MG Chemicals 835 rosin-based liquid flux. It's suitable for use with leaded and lead free solder, and a 100mL bottle seems to last me forever (even with regular use). I use a plastic squeeze bottle with a syringe tip to apply it. It's really useful when soldering to a large heat s...

Yeah, the net result of my simulations is that motor tun caps are way, massively, overkill for any normal service considerations. I have not dug deeply into Solen caps, but even ordinary box caps are fine for all but the first filter cap. Film caps with some special-ness should be fine if they can ...