Tube Amp Archive

The tremolo could be a bit deeper at 10, but it's plenty slow at 1 (i used three 20nf caps). I changed the 68k resistor at the intensity pot wiper to a 39k and it gets plenty deep now, even though i don't really like the taper of the on/off 50kC pot that I used. The tremolo isn't really noticeable ...

Got rid of the ticking noise after grounding the preamp separately at the chassis (not on the same cap can gnd as the powertubes, but rather a separate bolt to the chassis). I also tried isolating the input jacks but found it made everything noisy again if the cap can gnd is shared by preamp and pow...

Ok I'm basically done and it fired up first time! I used the help of a local amp builder to savely check everything out and slowly fire it up with a variac. I got the cabinet made by belgian guy with navy bronco tolex and a wheat grill. A few issues: - 50hz hum which is modulated by the reverb pot. ...

Unfortunately the power transformer was shorted and I had to get the replacement from Antique electronic supply. The closest to mine I could find is a little bigger, so I will have to enlarge the hole in the chassis , but the owner is ok with it. How is that even considered an acceptable option for...

This is taking longer than I thought because I got distracted with the holidays and other projects. Progress so far has been slow but steady: - I collected most of the components, all the iron, resistors and caps based on my schematic. - I learned how to use inkscape and designed a front plate that ...

I think I identified the mistake. There were several ground loops and current loops (power amp and preamp grounds tied together and weirdly looped). I read a lot about grounding (aikenamps and valve wizard stuff) and redid and separated the preamp and power amp grounds and now it seems the rattling ...

maybe put it on a switch

Thanks guys! Great insight.

I'm currently building a reverb pedal and already have a trem so will try that. Do you reckon it's comparable to the amp then? Because I would assume trem before reverb would be the more natural order, as trem pedals into amps with reverb is really common. On the other hand, these amps pretty much p...

yeah ok, so I came here essentially to calibrate my expectations. Sounds like this is normal. They are brand new and look a bit used lol. But as long as they work, fine.

I'm not expecting to build a work of art outright.

For my first amp project, a vibro champ variant, I ordered some mojotone transformers (made by heyboer afaik?).

They look a bit dirty/crusty cosmetically (especially that PT). Are these ok to use, or should I return them?

Ah gotcha

didit wrote: ↑Tue Nov 05, 2019 2:25 pm And actually it will precisely stock Vibrochamp. Analysis worked from power out back toward the input is more accurate to understanding generally, and certainly in this case.

Hi Ian, I don't understand this sentence.

The tremolo signal perhaps should get injected into final preamp V3B, thus avoiding putting it through the reverb circuit. What's the advantage of this? It would be closer to the princeton in that way, but it feels more intuitive to have trem before reverb (similar to a pedal going into the amp). T...

Many thanks!

The standalone reverb seems to have voltages below 300v as well