The FX Loop and Master Volumes

This is almost equal to the MESA design, except for the dedicated Master volumes for each channel.

My initial design featured a parallel FX loop with a Wet/Dry blending control, but the amp was oscillating with the FX plugged and I decided to go back to the simpler series loop.

It works nice with my Boss SE-50, although it can overload stomp boxes if the levels are not carefully adjusted.

The Master control works for all three channels and sets the overall volume level. When the Green channel is selected, R1B and R2B are at their "normal" positions, so neither the Red Master nor the Yellow Master are functional. When the Yellow channel is selected, R1B is activated and the Yellow Master lets you balance the Yellow channel volume to the Green channel. Red Master is defeated. When the Red channel is selected, both R1B and R2B are activated and the Red Master control is working while the Yellow Master is out of the circuit.

There's a deep switch that lets more bottom end reach the power section, in case I'm using a cabinet that can stand it. I also used 22µF caps to bypass the cathodes like the Fenders (unlike 15µF or 3.3µF like the MESAS) because I like that Fender fat. If you find out your cabinet is farting (like some Fenders do), go for the lower valued caps. You can also reduce the interstage coupling caps (I used mostly 47nF and 100nF).

I used a 12AX7 here.

Back to the AR-15 index page.

This page hosted by Get your own Free Homepage