Bad Cat Hot Cat "Gain" channel static noise?

[chuckb]

Hey chuck,No problem,thanks for all your help. I'll do a search and see what I can find.

Chuck.

[Chuck H]

It looks to me that grid leak tends to be more sensitive to proper circuit wiring from a noise perspective. The leak resistor should be right on the socket otherwise it can be noisy. At least thats what I read. And it's also bad about being overdriven producing an ugly distortion when preamp based pedals are used in front of it. Though I guess that's not an issue with a "gain" channel. Still, I did notice that a lot of builders choose the more common cathode bias arrangement when building these amps. It wouldn't be hard to try it if your inclined. Not much difference in tone reported from guys who have tried it both ways. You'll want to use a fully bypassed cathode resistor (1k or 1.5k resistor with a 10uf or larger cap across it) and a 1M 0V reference as seen od nearly all guitar amps.

[chuckb]

Hey chuck, I went ahead and put a 22uf/50v cap with a 1.5 resistor on the cathode and it works pretty good. I found it to be an improvement from the way it was. Thanks for your help,much appreciated.

Chuck.

[Chuck H]

K, good then. I'll assume that's a 1.5k resistor and not a 1.5 ohm resistor, right? Also, be sure your grid to ground resistor is 1M. Also be sure the 1M grid to ground resistor is moved to the input jack BEHIND the 68k series resistor (if it has one) otherwise it forms a voltage divider that will reduce gain. Did you try it with the input cap removed?
Now that you have a cathode bias you can reduce bass frequencies by reducing the size of the bypass cap. You can drop about 6dB from a chosen knee frequency by using lower values. Some will argue the specific frequencies and tout the inhearant frequency limitations of guitar amps but I hear a clear difference between different values up to 3.3uf. So maybe try a .68 (typical Marshall "bright" channel value), 1uf, 2.2uf and 3.3uf. Choose the one that de-muddifies (technical term) the tone to your liking.

[chuckb]

Hey chuck, Yes,I used a 1.5k resistor for the cathode bias arrangement.I have the 1M grid resistoron the input jack as you mentioned. I didn't remove the input cap,but I'll try it and see what difference it makes. I'll also try different caps as well in the cathode arrangement a and see what kind of difference it makes to the tone,(de-muddifies). I'll let you know how things work out when I've tried some of your suggestion.

Chuck.

[guitarmike2107]

HA me too chuck, I heard a difference going from 22uf to 47uf, it was subtle but helped my 1974 clone allot. I cant explain it, maybe the bass just gets less smeared or maybe it was the ESR of the different caps?

chuckB if you use a higher value resistor, 2.7k to 4.7k on the cathode you will get slightly more compression from that stage too, which will also help the tightness.

[chuckb]

Hey guitarmike21o7, thanks for the info. I'll give the higher value resistors a try as well.

chuck.