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Hello folks,
I just remembered a very weird & possibly unique issue I had with a brand new Lonestar Special.
When you switched from 10watt to 30watt position, the amp would put out this (for lack of a better description) 'whooshing' sound. Also the guitar sound would have the 'whooshing' sound, too.
If we removed all but the PI & power tubes, it would still Whoosh.
We did all the obvious things like replacing tubes, etc.
I believe you could hear the Whooshing in the send jack even with all tubes removed but PI & power tubes...yeah, very weird.
If you removed one of the power tubes (I think one of the outer ones) the whooshing would stop, but if you immediately put the tube back in, the whooshing would not start again.
It was very intermittent & you could never get it to act up while you were working on it long enough to get any indications either with meter or scope.
Since it was under warranty & very weird & Intermittent, Mesa agreed to take it for repair.
George found that there was some weird residue on the clad side of the pcb that was causing resistive connection where it shouldn't be. He also indicated that he's seen this from the pcb manufacturer before, but only a few times.
We, of course, would not have thought to remove the pcb as we all know how much fun that is on a Mesa.
Just an FYI of what you might encounter with a very strange Mesa problem. glen
I just remembered a very weird & possibly unique issue I had with a brand new Lonestar Special.
When you switched from 10watt to 30watt position, the amp would put out this (for lack of a better description) 'whooshing' sound. Also the guitar sound would have the 'whooshing' sound, too.
If we removed all but the PI & power tubes, it would still Whoosh.
We did all the obvious things like replacing tubes, etc.
I believe you could hear the Whooshing in the send jack even with all tubes removed but PI & power tubes...yeah, very weird.
If you removed one of the power tubes (I think one of the outer ones) the whooshing would stop, but if you immediately put the tube back in, the whooshing would not start again.
It was very intermittent & you could never get it to act up while you were working on it long enough to get any indications either with meter or scope.
Since it was under warranty & very weird & Intermittent, Mesa agreed to take it for repair.
George found that there was some weird residue on the clad side of the pcb that was causing resistive connection where it shouldn't be. He also indicated that he's seen this from the pcb manufacturer before, but only a few times.
We, of course, would not have thought to remove the pcb as we all know how much fun that is on a Mesa.
Just an FYI of what you might encounter with a very strange Mesa problem. glen