330pf on Champ power tube

[Tonewood]

On the 6v6 of my Champ, there is a 330pf cap from grid to cathode where it meets the 25mf bypass cap. Is this just dumping highs through the 25mf to ground or is it some kind of feedback that I don't get?

Thanks

[jrfrond]

That's a snubber cap, to reduce possible oscillation at the power tube grid. It might not even be needed, and in my opinion, anything higher than 100pF is not needed.

[echuta13]

Fender put snubbers in their later amps due to sloppy wiring. I'd be inclined to clip the cap, and just make sure the wiring is tidy.

[jmaf]

On the 6v6 of my Champ, there is a 330pf cap from grid to cathode where it meets the 25mf bypass cap. Is this just dumping highs through the 25mf to ground or is it some kind of feedback that I don't get?

Thanks

You can probably remove that 330 pf cap and add a 1.5k series resistor(grid stopper) on the grid, I think most older fenders didn't have the grid stoppers. The RC constant formed by the internal capacitance and that resistor will filter out RF without killing as much AF high end.

[mooreamps]

I would leave it in. That cap helps prevent the power tube from breaking into high frequency oscillations...
and use the grid stop.....

-g

[riz]

I am tinkering with a silverface champ right now. The first thing I did was clip out that cap. So far this one works fine, and the sound is improved a bit. It was very dull before. You can always add the cap back in if need be. It is my understanding that by this point Fender was installing these caps whether the amp "needed" them or not: no-one was getting paid to find out!

[Tonewood]

Thanks

Thanks riz, mooreamps, jmaf, echuta13 & jrfrond

scott