MT-15 Volume Change

[Dakota3711]

Hey there,

I was having some house work done and loaned my MT-15 out to a friend for the week. I do not gig with this amp. I have it as a practice amp that I always just leave at home. Since new, there has not been any problems with it. When I got it back after a week, it seems like the clean channel doesn't have the volume it once had. Also the lead channel doesn't seem to have the same grit anymore. In order to get any useable volume from the clean channel, I am having to turn it up to about the noon position. I have tried rolling preamp tubes to see if it was a faulty tube or not and nothing changed. Any ideas as what to try next? I trust my friend as he really cares about his equipment and is sensitive to how equipment is treated, so I don't think it is from anything he may have done.

 

[László]

Hey there,

I was having some house work done and loaned my MT-15 out to a friend for the week. I do not gig with this amp. I have it as a practice amp that I always just leave at home. Since new, there has not been any problems with it. When I got it back after a week, it seems like the clean channel doesn't have the volume it once had. Also the lead channel doesn't seem to have the same grit anymore. In order to get any useable volume from the clean channel, I am having to turn it up to about the noon position. I have tried rolling preamp tubes to see if it was a faulty tube or not and nothing changed. Any ideas as what to try next? I trust my friend as he really cares about his equipment and is sensitive to how equipment is treated, so I don't think it is from anything he may have done.

Usually a volume drop is worn power tubes, not preamp tubes. Might want to check that?

 

[Dakota3711]

Usually a volume drop is worn power tubes, not preamp tubes. Might want to check that?

I have also swapped the power tubes. No difference. Thank you.

 

[László]

I have also swapped the power tubes. No difference. Thank you.

Sounds like time to have it looked at, then! If it's still under warranty, PRS will fix you up.

 

[shimmilou]

Maybe some settings changed by your friend. Is the power switch set the same as before? Plugged into the same impedance output jack? Push pull boost knob?

 

[Dakota3711]

Maybe some settings changed by your friend. Is the power switch set the same as before? Plugged into the same impedance output jack? Push pull boost knob?

All settings are back to where I had them. I took a pic before lending.

 

[andy474x]

If your clean volume is significantly less and you’re also getting less dirt on the lead channel, it really sounds like you have a problem either with the V1 tube which is split between both channels, or something in your signal chain before that, maybe even before the amp. Have you checked cables, pedal board, guitar, etc.?

 

[shimmilou]

It could be that maybe you are imagining a problem that doesn’t exist?

 

[Dakota3711]

If your clean volume is significantly less and you’re also getting less dirt on the lead channel, it really sounds like you have a problem either with the V1 tube which is split between both channels, or something in your signal chain before that, maybe even before the amp. Have you checked cables, pedal board, guitar, etc.?

Rolled the tubes and no change. Pulled the two pedals out of the loop and was running straight in. I was using a new cable I just bought.

Put the meter to the cable and was finding signal from the ground to the hot. Not much of one, but enough that it impacted the input signal. Switched to a different cable and we are back to the way I remember. One would think that I wouldn’t have to test a brand new cable, but there it was.

Thanks to all who contributed their thoughts and ideas.

 

[Dakota3711]

It could be that maybe you are imagining a problem that doesn’t exist?

Oh, it existed alright!

 

[Deleted member 5962]

Oh, it existed alright!

TBH, I must have missed pedals, loop, etc., because that’s ALWAYS the first thing I recommend anyone to check. When it doubt, guitar>amp>cab and nothing else. Then re-add one thing at a time.

 

[László]

Rolled the tubes and no change. Pulled the two pedals out of the loop and was running straight in. I was using a new cable I just bought.

Put the meter to the cable and was finding signal from the ground to the hot. Not much of one, but enough that it impacted the input signal. Switched to a different cable and we are back to the way I remember. One would think that I wouldn’t have to test a brand new cable, but there it was.

Thanks to all who contributed their thoughts and ideas.

So great that you got it figured out!

Isn't it funny how sometimes the simplest things are the last things we check?