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Topics - Mprall00

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Attached is the schematic for an epiphone galaxie 10.  I have modded it heavily as a learning experience following another board's advice.  First thing I did years ago was cut the negative feedback resistor out (R15) but now thought I would like to add it back in on a switch to try values.

I wired it like the picture attached in place of R15.  I had tested the switch prior to hooking it up.  All good to go.  Attached it and fired it up - no change in sound at all between 33k, 10k, and negative feedback off.  That can't be right right?

So I took it back apart and used my multimeter to measure the switch on board and every setting (even off) measured 1.5k.

So I took the switch out entirely and measured between the pads - 1.5k.

So I wired a 33k in to r15 and measured on board - 1.5k.

Fired it up with 33k and sounded exactly like when I thought I had the negative feedback removed.

I mean it actually sounds really good after all the mods, but anyone know what is happening?  Can i not modify negative feedback loop in this amp?  Can I not even remove it?

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