Extra gain channel

[davidwpack]

Ello. I've been redrawing an Ampeg schematic and thought I'd attempt to modify to add a bit more gain with it's own EQ. I would probably breadboard the values for V2 or start at standard values and work from there. .just wondering if this would be an ideal way to go about switching V2 in and out of the circuit. Anyways for the interminably bored or just otherwise like looking at schematics...Thank Ye!...Dave

[shooter]

the voice in my head says you'll be making square waves real easy, so...
as an experiment wouldn't a tube-screamer N eq pedal get you there without soldering 

[davidwpack]

Probably but I'm one of the interminably bored.   I just wanted to figure out something a bit different for my winter project.

[sluckey]

V2 needs a grid resistor. The tone stacks are not quite right. Did you really mean for node A and node B to be connected together?

[davidwpack]

No. I guess both nodes are both "A". I was trying to figure a way around Ampeg's schematic. It bugged me for some reason. On Ampeg's version (B25-B) , there's a 1k and 10k paralled and node A is connected to C. I put the 1k directly on the tubes to remove it from the rail. Yeah I forgot the grid resistor. I'm not seeing my error on the tone stack. I'll look at it some more though. Thanks for taking a look at it guys.

[davidwpack]

Didn't ground the tone stack.

[sluckey]

That 10K and 1K are not parallel. Node A connects to node B thru the 1K. Node A connects to node C thru the 10K. It's two separate/different branches, not the more common series node string that you see in most amps. Some Matchless amps also use these separate branch B+ nodes.

Now compare the two tonestacks on the original Ampeg schematic. Channel 1 tonestack is correct, but there is an obvious error on the Channel 2 tonestack. And your tonestacks have a different error. Since you're bored I'll let you find it rather than give you the whole cookie. 

[davidwpack]

Wrong side of the cap going to ground? My eyeballs hurt.

[davidwpack]

Closer? Fixed the B+ rail (I think)
Edit: Updated schematic. (NFB, grid R, other stuff..and things.)

[sluckey]

 

[davidwpack]

Cool! Thanks!