Tube amp questions

[maxhifi]

Originally Posted by JohnCT

B+ at 220V would limit it's power a bit. Or, they didn't want to drive the outputs too much. It would be many years before distortion would be a *good* thing for guitar amps..

John

220V appears to be downstream of the field. I bet the field drops a good 50-100V, so B+ is probably in the 300V region as you'd expect it to be. That votage divider resistor in the power supply is sure old school! I really do wonder how it sounds.. 1930s guitar music is definitely interesting in it's own right.

[JohnCT]

Originally Posted by maxhifi

220V appears to be downstream of the field. I bet the field drops a good 50-100V, so B+ is probably in the 300V region as you'd expect it to be.

You're right - the 220V is indeed after the field coil. The output of the field coil (220V) is drawn closer to the rectifier, so that's where I goofed. Not all that clear on my phone, but on my desktop is much easier to see.

John

[mr_rye89]

This is very interesting to say the least. I'm not about to poo-poo building an amp designed in the 1930s because I use one every day. My homemade stereo amp is loosely based on the Western Electric 91A and makes 8 watts per channel. The biggest issue I see is the interstage/phase splitting transformer, But I'm sure Lundahl makes one though.

I'd also drop the first stage,I don't think it needs that much gain.

[JohnCT]

Originally Posted by mr_rye89

I'd also drop the first stage,I don't think it needs that much gain.

Makes one wonder about how much signal a 1930s guitar pickup would have?

John