Volume Question

[Mesa512]

Hello! I love my Mark V amp head. I bought it back in 2015. Back in 2015 I was playing the amp all the time and was consistently playing up until 2017. Then I moved, and had some major life events happen which caused me not to touch my amp for a while. However I am finally getting back to my normal ways. I set up my whole rig again and thought it would be a good idea to order a whole replacement set of tubes for the whole amp....everything preamp, power and rectifier. I used Mesa tubes 12AX7, 6L6, and 5U4GB. I changed all the tubes thinking it would be nice to have a fresh set in there since I neglected the amp for so long.

I plugged my guitar in and my tone sounds great. The only problem I am having is that I feel my amp is not as loud as before. No matter the setting 10W/45W/90W I just find I have to put the output volume higher than I usually would. I double and triple checked all my setting on the front and back panel and nothing has changed. I tried researching the issue, reading on the Mesa troubleshooting website but have not been able to figure it out. I can't tell if this is all in my head or if the output volume is in fact reduced. I am a fairly handy person and would like to try and figure this out myself before I bring it to a Mesa repair shop. Maybe there is something obvious that I am missing. What do you guys think?

 

[Don]

If you still have the old tubes, try them in the amp. Try the rectifier and preamp tubes individually and the power tubes in pairs. If any make it better, see about getting the offending tubes replaced.

There's no need to replace tubes because the amp sat. Tubes aren't affected by aging unless the pins corrode.

 

[Mesa512]

If you still have the old tubes, try them in the amp. Try the rectifier and preamp tubes individually and the power tubes in pairs. If any make it better, see about getting the offending tubes replaced.

There's no need to replace tubes because the amp sat. Tubes aren't affected by aging unless the pins corrode.

Okay, I will give it a shot. I have all the old tubes, I kept them all just in case. My only issue is that when I put the powertubes away, I randomly placed them on the floor and as a result they are no longer in their matched pairs. All 4 of the power tubes have the "YEL" indicator on them. Would I do any harm if I just randomly placed them back in the amp in no particular order? But regarding the preamp and rectifier tubes I will put all the old ones in and see if it makes any difference. I will attempt this when I get home from work tonight. I will report back on my results. Thank you for the idea.

 

[mace]

Hi,

Yellow is yellow so no issues there with placing them in random order. Reinstall the old tubes and note the order as ‘config 1”. If it doesn’t seem as loud with the old tubes, just flip the inner left tube with the outer right and call this “config 2”. If both config 1 and 2 are soft at 90W then the issue isn’t the new power tubes. If the loudness is back to normal then the issue is with the new power tubes.

Edit: the fact that you mention loss of volume in 10W, 45W and 90W power indicates that it isn’t likely a single power tube. In the head version, when looking from the rear, the 10W mode uses the 2 left tubes, 45W mode uses the 2 inner tubes and 90W mode uses all 4 tubes. The bad tube could be left inner one, which is used by all modes.

I know you said you double checked all knobs but the SEND level knob on the back is at the same position you used to run it?

 

[Mesa512]

Hi,

Yellow is yellow so no issues there with placing them in random order. Reinstall the old tubes and note the order as ‘config 1”. If it doesn’t seem as loud with the old tubes, just flip the inner left tube with the outer right and call this “config 2”. If both config 1 and 2 are soft at 90W then the issue isn’t the new power tubes. If the loudness is back to normal then the issue is with the new power tubes.

Edit: the fact that you mention loss of volume in 10W, 45W and 90W power indicates that it isn’t likely a single power tube. In the head version, when looking from the rear, the 10W mode uses the 2 left tubes, 45W mode uses the 2 inner tubes and 90W mode uses all 4 tubes. The bad tube could be left inner one, which is used by all modes.

I know you said you double checked all knobs but the SEND level knob on the back is at the same position you used to run it?

Thanks, good info on the yellow designation. I had a feeling that it wouldn't matter since they were all yellow, but I wanted to check with you guys first before doing anything. I will be sure to try the different configurations as you mentioned to see if the left inner one is the problem. And yes, I made sure to double if not triple check the SEND knob in the back. It is at the same level as before. I will report back if any of your troubleshooting configurations solves the problem. Thanks again for your help

 

[Mesa512]

Okay so I did as you mentioned above. I basically took all my old power tubes and put them back in random order. The first thing I noticed is an improvement in volume. Also when I would switch my amp from standby to on I was hearing a popping noise. Now that I put my old tubes back in that noise does not happen anymore. As far as I can tell, my issue has been resolved. I am a little surprised that I had this issue with brand new tubes directly from Mesa. Oh well, all I care is that my amp is back to normal. Just wanted to thank everyone for their help/advice. Very much appreciated.

 

[jaslan]

You may have missed “Mace’s” suggestion to check the send level knob on the back. Here, it gets put below an advertisement that “isolates” it on its own and is easy to miss. The FX send level can very significantly adjust the overall volume.