Single Rectifier Issue

[spire]

Hi, I've been the owner of a series II single recto for about two years now and have nothing but good things to say about it. Last night I was playing at our practice space and noticed that my volume was starting to fluctuate. I turned the amp off and let it cool down for a few minutes and when I turned it back on all the low end was gone. It sounded like just the preamp without the poweramp if that makes any sense. Just very tinny and weak. I assumed it was a tube issue, but I have several different sets of power tubes and they all do the same thing. I don't have any extra preamp tubes, but I switched them all around and it did nothing. For some reason the clean/pushed channel sounds fine. I tried different cables, different guitar, different tubes, and nothing helped. If you guys have any idea what the problem might be, please voice your thoughts. Thanks.

 

[clutch71]

If your sure the power tubes are good and at a rating suitable for Mesa's fixed bias and it's still doing it...tech time.

Especally since what you are describing sounds like the tell tale signs of failing power tubes.

 

[fishyfishfish]

+1. Change out your preamp tubes one at a time like the manual says and if that dose not work take it to a tech.

 

[spire]

Well, I fully retubed it and no luck. Still did the same thing, so I took it to a tech. He called me back and said he did a full diagnostic on it and could find absolutely nothing wrong with it. The store is a licensed Mesa dealer, and he has been working on Mesas for years. Could this be a cabinet problem?

 

[clutch71]

Is the problem recurring wherever you plug it in? Another cab is not a bad idea but I thought you tried different speaker cables?