Carvin X amp question

[xtian]

I got a mint Carvin XT112 (50w) for cheap. I love it! I have converted three Carvins to ODS, but this will will stay stock...for a while at least.

What's this RC network doing? It's part of the clean channel:

carvin_xt112.jpg

X-Series_Amp_Schematic.pdf

[martin manning]

Notch or band-stop filter, simplified version of a Twin-T. That one is a mid-scoop around 400Hz.

[Phil_S]

Yeah, notch filter. If simple to install a temporary bypass, you should be able to hear what it does and whether you like it or not. Maybe it will lead you to install a switch?

[xtian]

Perfect. My ears were telling me there was am EQ scoop. I'll bet that's Carvin's attempt to make the clean channel Fendery. The tone controls are very nice, uniform sweep with pot rotation, especially the Presence control, where mine are always limited to a small part of the rotation. I see a lot of op amps in this circuit; active tone controls.

[roberto]

Put a trimmer (or pot) between C13 and ground, and you will control the amount of scoop.
You can even convert it into a tone control, à la DrZ Carmen Ghia.