Dumb tube Q - Bad Cat

[grankin]

Cross-posted from 'Amps & cabs' ...

OK, so I'm a clueless newbie when it comes to tube amps. I've got me a Hot Cat 30 which I like, and the amp's been used relatively sparingly in-house for 2 years.

The high gain channel has lots of tube rush which mostly goes away when I cut "level" way back and compensate by cranking "master" up to "11". What's the prob? Need new tubes? Which ones? I suspect (not being all that literate with tube circuit diagrams) that it is in one or more of the preamp tubes in the high-gain section, and not in the power tubes.

Any advice gratefully received. TIA!

[Sherman]

Does the white noise on the gain go away when the clean channel volume is reduced? Does the tone change on the gain channel in any way when you reduce the volume of the clean channel?

[Blue Strat]

Cross-posted from 'Amps & cabs' ...

OK, so I'm a clueless newbie when it comes to tube amps. I've got me a Hot Cat 30 which I like, and the amp's been used relatively sparingly in-house for 2 years.

The high gain channel has lots of tube rush which mostly goes away when I cut "level" way back and compensate by cranking "master" up to "11". What's the prob? Need new tubes? Which ones? I suspect (not being all that literate with tube circuit diagrams) that it is in one or more of the preamp tubes in the high-gain section, and not in the power tubes.

Any advice gratefully received. TIA!

Either V1 or V2 tubes might be noisy (the two furthest from the power tubes) or there could be a noise problem internal to the amp. The only way to know is to try new tubes. You need spares so you can troubleshoot issues like this anyway. Cranking the channel volume will expose noise issues in any amp.