op amp gain in parametric EQ question

[blackieNYC]

I'd like a little more gain out of this EQ.  It's a little low when I notch.  It is already built, and I did put a volume control in place of the 10k. So I could increase R7, but could I instead lower the value of R9?  Or will the three band gain pots interfere with that? It would be easier in this build to just tack on another 10K in parallel with that.  As opposed to removing R7.

[PRR]

R9, Q1 Q2 Q3, R7 are all in a defined relationship.

Boosting before a notch begs for overload.

A 2:1 voltage-divider on the output will raise the output 6dB.



This should probably be switchable.

[blackieNYC]

Ooh. Wasn't expecting that. A moment of headscratching...  This will result in the voltage at the FB loop being cut in half. Negative FB loop, that is. OK. Doubling the FB resistor - that wouldn't work here? is the relationship you mention in this particular circuit complicating the "usual" gain-role of the FB resistor?
You're not gonna let me get away with tacking on a resistor in parallel. Making me cut connections on my messy perf and spaghetti wiring. Hmph. Oh, okay.

[PRR]

> relationship you mention in this particular circuit complicating the "usual" gain-role

The stock values lead to symmetric boost-cut of predictable amount.

Different values complicate things too much for me; frankly _I_ think it is easier for you to hack it than for me to think about it.