reverb problem on mesa .50

[JC@]

I have a problem with a mesa .50
The reverb is almost non-existent but I noticed that using a different pan, borrowed from a Twin Reverb, same size but different type, there's a little more reverb effect.

Everything looks ok, the voltages on the reverb tube are ok, the only thing I haven't tested is the reverb transformer.

When I smash the pan there's a faint spongy noise coming out the speaker, not the usual huge blong-blong noise.

Please help

[Tom Phillips]

I have a problem with a mesa .50
When I smash the pan there's a faint spongy noise coming out the speaker, not the usual huge blong-blong noise.

That indicates that the problem is in the reverb return circuit. Look there. (Return tube, voltages, connecting cable continuity etc.) The reverb transformer is part of the drive circit so, unless two things went wrong, it is most likely OK.

[Enzo]

Right in, and the first thing I would check on that end is the cable.

[JC@]

There's something wrong here with this amp.
Now there's almost enough reverb using the other pan, but still nothing using it's own.
The reverb effect is not as big and deep as fender's, but it is ok. So maybe there's something wrong with the pan, something I can't find.

Anyway, I get 1 whole volt dc on the grid of the return half even with the pan disconnected, don't know why. All the rest of the voltage readings are ok.

[Tom Phillips]

I'm looking at the schematic of the Mesa .50 Caliber+. Do you have a schematic and is that the amp you are working on? On mine the reverb pan output transducer coil serves as the grid leak resistor for the recovery stage. I think the reason you are measuring voltage on the grid is 1) a bad tube or 2) the open circuit condition with no pan or a bad pan connected if that was the condition when you measured.

The mesa reverb is a lot weaker than a Fender due to the design so it sounds to me like you have a bad pan. If you want to check further, you can measure the resistance of the pan with an Ohmmeter. The input transducer should measure around 1 Ohm and the output transducer should measure a couple of hundred Ohms. They usually measure way high or open circuit when they go bad. Check for a broken wire inside the pan if the readings are too high. If you don't find anything then it's just time for a new pan.

Regards,
Tom

[JC@]

solved, the owner prefers using an effects board

The reverb pan is bad for some unknown reason. There is about 1 ohm at one end, almost 200 ohms on the other. The cables are ok. The springs have good tension and are reasonably clean. But it doesn't work.

The owner prefers using external effect instead of waiting for a new pan, a real pity now that the reverb circuit is working perfectly.

ok then... off he goes.

[jak0lantern01]

Just as an FYI: that amp has very weak reverb to begin with. I own one, and my friend who loves a totally saturated reverb sound hates it, it doesn't cover-up his sound enough. Why they're called Recto-Verb is beyond me, but it's adequate if you're not a big reverb guy, which doesn't sound to be the case with you. Did you test it before purchasing?

[JC@]

I'm not the owner actually.
Just repairing it for someone else.Yes it does have reverb, but nothing like a fender or an old ampeg.

I feel a bit shamed because after all this posting I found that the reverb now works.
Quite different than a Fender or a vintage Ampeg, but it does have reverb.

I repaired the reverb circuit, clened the springs because they were sticky etc but the fact is that the reverb is working now.

[adamshack]

I'm having the same issue with my dual caliber DC-5. I love that classic reverb sound from my twin reverb. But i cant get that from this amp. It just sounds kind of dissonant, and a little too transparent. Does anyone know of any mods to get more reverb from this amp ?