Bogen K15 tone stack

[canterbury]

I wasnt quite sure where to post this. But you guys have been a great help in the past so I figured this is a good place to start. Almost a year ago I converted the inputs on this amp for guitar use. Its been running great all this time, no issues that I can see or hear. My only real issue with the amp is that the tone stack is just about useless. I have to keep both controls maxed out for it to be useful. Ive done a lot of searching and reading on the internet about tone circuits and I'm really more confused now then when I started. So I need some help. I've attached the schematic for my amp, other than changing the inputs the amp is stock. I can solder. I know the basic function of each the components. But I really have no idea how they work together in this circuit. So what I'm looking for is some help with changing this tone circuit to something more useful for guitar. Thanks for any help in advance.

[dwhutchens]

What about this? I don't know if it will cause too much insertion loss or not. If so maybe just a simple treble control. It might also work better before the 6av6 instead of after, it was easier to paste it over the existing tone circuit.
David

[canterbury]

What about something with only Bass/Treble. I really dont want to go drilling extra holes in this chassis.

[dwhutchens]

Change the mid control pot to a 6800 ohm resistor, that appears to be the difference between the Fender bass and treble vs. bass treble and middle controls. I've wired it both ways.
David

[canterbury]

Thanks for the replys. I'm gonna give this a shot. BTW how would I know if there was too much insertion loss?

[Enzo]

The signal would be too much less loud for you after the change.

Here, check out Duncan's Tone Stack Calculator. It is a little program that lets you see graphically the changes in response to changes in your tone stack, including the ability to operate the controls in real time.

http://www.duncanamps.com/tsc/index.html

[canterbury]

I'm going to order parts for this today. I wanted to make sure I was getting the right stuff. What sort of voltage ratings do these capacitors need to be?

[dwhutchens]

Sorry, I missed this post. Took a break from my email for a few days. I just use 600v. they are not very big in these values, I used a silver mica for the 250pf.

[canterbury]

I got my mouser order in today and wired up the new tone stack this evening. I haven't had a chance to play on it much (sleeping kid), but from what I can tell so far I think I'm gonna be VERY pleased. Thanks dwhutchens, and everyone else, for all the help.