Fender 5F1 Champ Distorts too early

[Phil_S]

Caps connected in parallel are added together for total capacitance. If you want to experiment, all you need to do is tack in a 5uf next to a 20uf to get 25uf.

[JD0x0]

No bypass cap has the best bass response, as the stage should have the same gain at all frequencies, albeit, less gain than if you have the cathode bypassed. More NFB, should also widen the bandwidth, which would theoretically also improve bass response.

With most cathode resistors, once you get over 10-15uF for the bypass cap, you don't gain much audible bass response. Chopping off a little fundamental on your lowest strings isn't always a bad thing, either. Sometimes, it's required for the sound to not be boomy or muddy, especially with distortion.

[Yoda]

I had originally placed that 10uF cap because I thought it would help with bass response. It would have done so if that wasn't where the negative feedback was coming in. Either way, the 20uF in the first stage did more than enough for the bass response. I may even substitute the 25uF in the first stage with the 10uF I took out from the second stage. I think it's almost too bassy as is right now.

Great discussion!

You might be interested in this, I built a 5F1 Champ myself and it has switchable bypass capacitors on both preamp stages and just as you are describing differences in capacitor values, I also experimented with them and found that I like the first stage bypassed at 10uF for fat bassy tones but the second stage unbypassed most of the time with the negative feedback on.

Occasionally I will switch the second stage to the 0.68uF bypass setting to boost mids and highs significantly and really makes the amp cut more aggressively but the 10uF position doesn’t sound good for the second stage but I can’t tell if the muddyness comes from the 10uF capacitor or by virtue of all the negative feedback signal being grounded in the 10uF position, so I never use it. But 10uF sounds great on the first stage!

[Johnny_March]

Wow that's very nice work!