Tremoverb clean channel hiss

[pipboy90]

Tremoverb owners/players out there, is a significant amount of hiss on the clean channel of the Tremoverb normal? I don't hear it on any of the other 3 channels, only the clean, with no guitar connected to the input. I swapped out all of the tubes for known good ones and cleaned the tube sockets with contact cleaner but the hiss remains. I've also tested the 6 blue Mesa filter caps with my Atlas ESR meter and they all check out. If I want to check the other caps I'd have to take the board out to get underneath it.

I'm thinking it's either the way the channel was designed or it's some failing component in the clean channel signal path that isn't active in the blues or vintage/modern high gain signal paths.

I've also read some other people complaining about hiss on the clean channels of other Mesa amps, like the 5:50 Express: https://boogieforum.com/threads/5-50-clean-channel-hissing.34052/. So maybe this is a design thing? Even if it is, I'd still like to try and fix it.

The amp I have was built in Feb 2000 and the insides look completely original. Pics attached of the insides, and here is a sound sample so you can hear what I'm talking about: https://www.dropbox.com/scl/fi/apdg...ey=o904gufu5cvrgb9qux5y6j9gj&st=4vhrrv5y&dl=0

The hiss gets louder/more defined when the Presence is turned up, which I guess makes sense because we're talking about high-end noise. I found the official schematic as well (attached). Is the next step to get an audio probe and try to trace the signal path until I find the bad component? I have technical experience with amps but I've never tried to hunt down the source of a noise before.

 

[RedPlated]

Pretty much every rev G that’s come through here ( a lot lately, over 30 ), including Trems, has a hissing clean channel. It’s got to be a design issue. It’s an archaic channel switching design.

I’ve never dug into it because it’s probably pointless. But no one really gets these for the cleans anyway.

 

[pipboy90]

Pretty much every rev G that’s come through here ( a lot lately, over 30 ), including Trems, has a hissing clean channel. It’s got to be a design issue. It’s an archaic channel switching design.

I’ve never dug into it because it’s probably pointless. But no one really gets these for the cleans anyway.

Damn, really? I’m surprised I haven’t heard many people mention it when talking about the Tremoverb’s cleans. If that’s the case I’ll have to put it in the to-mod list once I learn a bit more about circuit design.

Thanks for letting me know .

 

[skoora]

Mine doesn’t hiss on the clean channel. I’ve never heard significant hiss out of a recto on the clean setting and I sold G’s and Tremoverb for years in the 90’s.

 

[pipboy90]

Mine doesn’t hiss on the clean channel. I’ve never heard significant hiss out of a recto on the clean setting and I sold G’s and Tremoverb for years in the 90’s.

Very interesting. The plot thickens...

 

[skoora]

Very interesting. The plot thickens...

I haven’t consistently heard G’s or other Tremoverb’s since the 90’s so it’s not necessarily scientific. I could have lucked out on my current T-Verb and maybe the hiss comes in after a certain number of years with a common value drift or failure? I’m not discounting redplated’s experience over mine. I was experiencing them mostly as brand new amps.

 

[pipboy90]

I haven’t consistently heard G’s or other Tremoverb’s since the 90’s so it’s not necessarily scientific. I could have lucked out on my current T-Verb and maybe the hiss comes in after a certain number of years with a common value drift or failure? I’m not discounting redplated’s experience over mine. I was experiencing them mostly as brand new amps.

I think your theory about component drift/failure over time could be spot on. I guess the only way to know for sure is to do a deep dive and start testing individual component values related to the clean channel.

 

[skoora]

Granted, I’ve got the gain up on the clean setting 2 O’Clock and it’s a phone recording but I’m also using a P-90 and not getting any hiss or noise that’s too much. It’s on Diode rec and bold. Playing’s a little cattywampus as my Thumb has a thing going on where I can’t grip the pick well.

Tremoverb

 

[pipboy90]

Interesting. I think I’ll have to start chopsticking parts