Banana Booster Help

[Freekmagnet]

I'm building my very first tube pedal found here:

http://www.tube-town.net/diy/lov/lov03-bananabooster-eng.html

The only change I made is that I added a 50K pot to replace R1 on the layout as a gain control.

Doesn't seem to be doing too much boosting. I'm getting a really quiet signal that sounds pretty distorted. Also, the volume seems to be working backwards.

I know almost nothing about tubes - like I said, this is my first stab at it. Any suggestions?

Thanks!

[Mark Hammer]

I have to admit that when I saw the header, I thought it was one of those posts that have seeped into the forum since the breach the other day.  I mean, you have to admit that it doesn't take the receipt of that much e-mail spam for "banana booster help" to look a little, well, Freudian.

You probably don't want to fiddle around with R1.  Leave the gain of stage 1 as is.  Instead, consider making R6 a 470k log pot instead of leaving it as a fixed resistor.  This will let you pad down the output of V1a to drive V1b with different amounts of "push".

[Freekmagnet]

Thanks, Mark. I'll look into that. Makes sense because I don't get much signal until the pot tops out. I suppose this is what I get for monkeying around with circuits I don't understand.

I don't have a 470k pot laying around, so in the meantime, I have my tube voltages @ 12.6v:

1. .25v
2. 6.7v
3. 7v
4. 0v
5. 12.6v
6. 0v
7. 12.6v
8. 12.6v