Yikes JP; adults have amps like the Mesa DC5 :shock: Reverb loop shown below, one channel only ..... sorry for the poor resolution; image went from Adobe to PowerPoint to Paint and up to the web ....
Sure, try switching out V5 but don't forget V3 and V4 that are the sources of the signal; if they're not working very well, the reverb circuit and V5 don't have a chance. If you have the amp open, good time for housekeeping. Don't forget to spray/clean the new-in tube pins and the sockets; could have some corrosion. If no change, this amp has two volume controls; one is the source of the to-the-reverb signal and the Master to which the signal returns; could be that either/both are dirty. Finally and depending on much of this you want to mess with, you might want to meter the reverb supply voltages; points B & D on the power supply and at the plates of V5; 416V and 118V respectively.
I note that the in/out of the reverb circuit are controlled by Relays RY3a and RY2b. The power side of the relay is easy; it either works or it doesn't but the signal side ... you can't really open the relay and clean the contacts - you can't do anything but replace it. Every time it's switched, a little bit of one contact is burned from one side to the other; like a power switch on an amp. Over time, the contacts slowly burn up and if the switch fails 'open' it won't do anything. If it fails closed, then must plug/unplug cord to turn amp on. In the meantime, a layer of corrosion forms on the contacts impeding/degrading the signal. My point is that the contacts inside the relay are a potential source of signal grief the fix for which does not come in a spray can (make that a maintenance man's much-beloved spray can :wink: ). If Mr. Mesa wanted to make nice-nice with downstream techs, the relays would be easy to pop in and out of sockets soldered to a pc board ... in which case ...
Insulated v. Grounded input; in the pic above the secondary side of the reverb transformer has one leg tied to the can/springs and the other leg directly to ground. On the output side, there is a shielded cable with the shield grounded, as is typical, at one end only. I interpret the drawing to show 'insulated' input; essentially one leg carrying the signal. In the more common scheme, the reverb can itself is the ground conductor and with either 1/4" or RCA jacks, the ground is continuous from the input, through the can, and out to wherever it goes. I think the goal in the design is noise control and eliminating yet another potential source of ground loop hum; unless you have reason to think there's something wrong with the wiring itself, I'm not sure I'd mess with it.
T'were me, I'd do the housekeeping and tube-rolling - it takes longer to write about it than it does to do it and I'd have a peek at how those relays are seated - before I switched out the can. Because I am immature and petty, I'd be pretty upset if I went out of pocket $50-odd only to find that the new can didn't make any difference at all .... :evil: :evil: :evil: .......
CJ