3CH Dual Recto Inconsistent

[madrigal77]

I have a buddy I jam with that has a 3ch Dual Recto that he's been having a bit of a problem with. He's not computer literate, so I thought I would ask here on his behalf.

The problem is that the amp has been very inconsistent. One jam it will sound killer, and then the next one it will sound very muddy and awful. He uses the same settings and puts the amp in the same spot every time. I know that's pretty vague, but I thought it might be a known issue and you Boogie experts might have an answer. My 5150 sounds the same every jam and he didn't have this problem with the JCM800 he had before the Boogie. My first thought is perhaps the power tubes need to be changed as they've been in the amp for 2 years now. Any other ideas than that?

 

[screamingdaisy]

If the power tubes are going it's usually consistently muddy, although after 2 years it might be worth it to replace them anyway.

If you have a multi-meter, try testing the voltage at the wall socket and make a note of the voltage and how it sounded on a particular day.

 

[fluff191]

If the power tubes are going it's usually consistently muddy, although after 2 years it might be worth it to replace them anyway.

+1

I would make sure he does not have russian preamp tubes in V3 and V4 as well.

 

[Anonymous]

If you have a multi-meter, try testing the voltage at the wall socket and make a note of the voltage and how it sounded on a particular day.

Big +1 here. Best thing I ever did was to buy a Variac so I can set the voltage exactly where I want it (Mesa specifies 117VAC). I measure as high as 124VAC at my place and as low as.... :shock: ....112VAC at my practice space.

Multiply that difference at the wall by the amount the power transformer produces and you have a swing of about 50V at the power tubes. You WILL notice that!

 

[madrigal77]

Thanks for the suggestions guys. I'll see about the multimeter. The thing is though I don't have that problem with my 5150 and he didn't have the problem with the JCM800. Are Mesa's just more sensitive to that kind of thing or something?

Also as far as the tubes, they are just the ones that came with the amp. I put a Tung Sol in V1 for him a couple of months ago, but everything else is stock.