Power Tube Grid Resistors

[Darkbluemurder]

I noticed that Dumble amps use either 3k3 for 6L6s (instead of the 1k5 used by Fender) and 5k6 for EL 34 (same as in Marshalls). My guess is that 3k3 would make the power amp slightly more stable than the 1k5. I currently have the 1k5 in my Concert and it sounds fine. Has anybody ever noticed a difference from such a change?

[MarkB]

Randall Aiken talks about increasing grid stoppers to prevent problems. If you go too high, you can start losing high frequencies, but I think he said you can go up to 50K before you hear it.

http://aikenamps.com/TI_Aiken_adv.htm


I think I'd use whatever I had the most of near 1.5K.

[llemtt]

I once made a mistake and putted 33k instead of 3k3, it took me weeks to understand why the amp sounded so dark

As soon as I replaced the correct values the amp returned to normal brightness, go higher than 5k1 and you'll definitely noticed it..

Teo

[swt]

It has to do with current, and tone. It's more stable, provides a steady current, and also rolls of some treble. Always solder those resistors to socket, to avoid oscillations. I like those values, because fender are low gain amps...but in high gain 3k3 is more stable for that kind of tone and tubes...