MkII C+ reverb question

[Mr. Blues]

The reverb on my 60 watt C+ is kinda weak. I've replaced the tube (12AX7) and checked all the connections but it is not as good as my old PV
MX pig rig or other boogies/fenders etc....What's the fix? different tank, replace stock tank? I've heard that you just can't slam another tank in your amp and that certain specs have to match? (which might be the reason why there was no improvement when I put in the PV 3 spring unit?)
Is the weak reverb common to C+s? or just my luck? Any ideas?

 

[Joey707]

There are 2 mods to boost the reverb on MKIIC+'s and MK III's. The simple one is as follows:
You need a 3.3K, 1/2 watt resistor. Place the resistor in series with the black wire at the EFFECTS RETURN JACK. So, remove the black wire from the effects return jack. Solder the resistor to where the wire was on the jack. Solder the wire to the other end of the resistor. Place heat shrink tubing on the resistor.
This will increase the amount of reverb. How much more you get depends on the tank. You do have to use the correct tank for the amp. The correct tank number is 9AB2A1B.
The second mod is more extensive. It involves changing some parts on the circuit board. You should contact Mike Bendenilli at Mesa for this mod. 707 778 6565. He's done this mod to all my MK III's and they have reverb for days.

 

[Mr. Blues]

I replaced the tank. There was a very slight increase in reverb.
I put in the resistor thingy and reverb is MUCH BETTER.
Would a different value resistor increase reverb any more or is this as good as it gets? Thanks again! - twang on

 

[Joey707]

I'm not sure what a different value resistor would do. I've never tried it. Mike would be the guy to ask.

 

[Henz]

Hello. I have a C+ as well . I know this a very old thread but I need to ask, there are two black wires going to return jack. One from reverb pot and the other one that's in that larger two conductor grey wire going to the other end of the 150k resistor on preamp board. And there's another short lead going to send Jack, all cramped on that one lug. Which black wire gets the 3.3? I have the exact reverse problem. I replaced tank as above with that model number and pot and cables and I have way to much verb. How can I tame that? Thanks, Jim

 

[GJgo]

I've had all the Marks, and even after having Mike B. work over the older ones the only one that ever sounded good with the stock reverb was the JP2C. The MKII and III reverbs have always been very uninspiring. IV is meh & V is passable. I don't know about this mod that's being spoken of, but I think you might be happier with a reverb pedal. FWIW & IMO.

 

[Henz]

Thanx for the reply. I upgraded my verb with new tank, cables and pot last year. I liked it. it made a noticable difference. but recently, something happened, i do not know what i did but the verb is way out there. Kinda thin and raspy. I'll just keep the thing off or get a pedal like you said if i feel i really need verb. I want that lush, deep verb if ya know what i mean. Thanx man, Blessings, Jim

 

[rarebitusa]

I agree with GJlo, the reverb with my IIC+ has never really been inspiring. Mesa reworked it a few years back and it was improved but honestly still kinda "meh". I run 4CM and use other reverb pedals in the fx loop which generally produce better results. Now in comparison the reverb in my Mark V that sounds really good

 

[Henz]

IMO, i think that Mike , Doug and Randall should have had the circuits better designed for the C+. But it probably was due to the RP11A Preamp board. I dont like how the verb and lead drive share tubes. C+'s V3 = 1/2 lead drive/verb return, V4 = 1/2 lead drive/ verb driver. I wish they had their own dedicated tube. But, as i said, may be due too the above board, maybe carried over from a MKIIC, not sure.

 

[GJgo]

Henz as you probably know they made this change on the MkIII.

 

[rarebitusa]

Well not to "pile on" too much but it's placement before the effects loop send is not optimal, to say the least, if you are actually using the loop.

 

[Henz]

Yes, I checked out a MKIII schematic. Looks real close to a C+. I read that the Rhythm 2 when pulled sounds very close to a C+. Does anyone know why the 120pf cap going to the return on a C+ was removed after August 1984? And what does it do? My C+ still has it. I see that the MKIII has a 10k resistor in series to the 47k instead. And like you said, the verb is before loop. Would having things in loop affect the verb?

 

[akamouzis]

I have a question about the reverb circuit. when you turn up the reverb pot, is that directly affecting the reverb driver tube V4B or the recovery tube V3A?

 

[Henz]

C+ ? Looking at C+ schematics, I would say recovery V3 A. Output on tank. I'm no tech but I don't think the verb pot affects tubes. Just blends wet dry signal.

 

[Henz]

So, which black wire Joey? There's 3 going there.Thanks, Jim.