Mark III reverb crackly?

[JeffMN]

Hi - I recently purchased a Mark III that I love. One of the things that I thought was awesome about this amp was that it had all the 'options' - reverb, EQ and Simul-class. The reverb isn't as 'strong' as other amps, and I guess I'm okay with that - I won't be using it that much anyway, just on some clean stuff with delays.

The thing is though, when I turn the reverb up, it seems to make the 'effected' tone (the reverb's tone) sound kinda trashy. If it's not up so loud, I can't really hear it, but I guess that would make sense as the dry tone is probably just winning over in the volume department.

I did just acquire this amp, so I haven't checked any tubes relating to this as of yet. Otherwise, the amp screams. I guess I'll ask the dumb question - is this how it's supposed to sound? I know there's a mod of some sort for the reverb on this amp, but haven't found anything about it - what does it do? Google seems to not tun up results detailing what this mod (or the Rhythm 2 mod) consist of, aside from 'sending it to Boogie'.

 

[Boogiebabies]

The reverb gets pushed by the master volume. It will be weak with low volumes. The crackle may be a dirty pot, reverb cables, reverb grounds or the preamp tube.
The mod is adding a 3.3K resistor as shown below.

 

[Henz]

Thanks BB. In my C+, which one of the two blacks does the resistor go to? The black lead to pot or the lead to the resistor arch? Thanks, Jim