Fender mixing/summing resistors

[EETStudent]

Im starting to build a super reverb clone, however only utilizing the normal channel. Do those 220k resistors do anything other than keep the channels away from each other?

[jrfrond]

Yep. You can leave out the resistor for a single-channel version.

[EETStudent]

What would leaving it in do?

[jrfrond]

220K would cause a slight drop in signal level. I'd be more concerned with the slight reduction in highs personally. However, if the signal level is where you want it, you can create a HF shelf response by bridging that resistor with a small cap, like 100pF silver-mica. It's really a spot you could experiment with freely with no ill effects.