# Glory hole gain switch mod possible ?



## Bobbyd67 (May 15, 2020)

I just ordered some glory hole pcbs and was wondering if it's at all possible to add the V4 gain switch as a mod ! Idunno how exactly the gain boost is triggered but if it's like a 1-2 resistors switch it should be easy ? 

Thanks in advance if anyone is familiar with the circuit and can help me out !! If not it's all good ^^ I will just build them stock


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## Robert (May 15, 2020)

The V4 looks like a significantly different circuit from the V3.

The toggle switch (and remote jack) appear to control a relay.    

The V4 looks to have four LEDs instead of standard diodes, and I suspect the symmetry is changed by the relay. It's also _probably_ altering the gain of one of the opamp stages.    This is all just speculation based on a pic, of course.


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## Bobbyd67 (May 15, 2020)

Thanks for the quick reply!  I'll just build it stock then  I ordered 2 so maybe I will build a double version like a KOT . Haven't decided yet !


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