Boost for clean and OD channels

[JammyDodger]

Hey All,

Is there a way to get more boost out of the PAB circuit? My pre-amp is the ODS-101-HRM.

Ultimately, I would like to get a larger boost in the PI stage so that whether I'm in the clean or OD mode, I can bump the signal up by stepping on a switch.

Any suggestions?

Cheers, Mike

[heisthl]

Instead of, or in addition to, the standard PAB arrangement you could "lift" the bass and Mid pots (disconnecting them from ground). This gives you a lot more gain.

[d95err]

Hey All,
Ultimately, I would like to get a larger boost in the PI stage so that whether I'm in the clean or OD mode, I can bump the signal up by stepping on a switch.

Do you mean that you want a volume ("solo") boost on both Clean and OD, rather than just a gain/frequency boost?

In that case, a preamp boost won't help you for the OD. Instead you should be looking at e.g. switching between two different master volumes or something like that. You could try the old Mesa trick to switch in a variable ("boost") resistor between the MV and ground.

[JammyDodger]

Instead of, or in addition to, the standard PAB arrangement you could "lift" the bass and Mid pots (disconnecting them from ground). This gives you a lot more gain.

I've seen this as an alternate version of the PAB, where the relay lifts the Bass and Mid grounds. Might try this.

The resistor on the MV sounds good too. Any idea what value resistor I should try?

Cheers, Mike

[Structo]

Usually it's the opposite of what you ask.
My boost was way too big.
I padded the PAB with a 10M resistor. It still is almost too much.
Mine lifts the bass, treble pots when engaged.
Something else I noticed is if the bass and treble pots are turned up quite a bit, the boost isn't as big probably because the wipers are closer to ground.

[JimiB]

You could try the old Mesa trick to switch in a variable ("boost") resistor between the MV and ground.

is that the "dual master volume" set up?