Mark III issues

[gummx97]

I just recently acquired a black stripe Mark III, I love the lead channel, I think the tone is just phenomenal. However, as being an old amp and bought it used, it has several issues:

I sprayed deoxit on the openings of all pots and also exercised them as well. Here's a more detailed description of what is happening after the pots were cleaned.

Volume 1 pot = the audio (volume) peaks as 7, anything past 7, and the audio slightly drops off. When the pot is pulled, it's the same thing, audio peaks at 7, and slightly drops past 7.

Treble pot appears to function normally, including the pull (shift) function.

Bass pot appears to function normally, including the pull (shift) function.

Middle pot has some problems. The mid frequencies seem to peak at around 3, go past 3 and the mid frequencies drop off, sounding kind of muddy. 3 seems to be the "sweet spot."

Master 1 pot functions normally.

Lead Drive pot functions normally.

Lead Master functions normally.

I don't think it's the tubes since the amp has a nice sparkling clean sound and the lead master has very high gain. What do you all think? I am thinking it is just a potentiometer issue...i don't know who the previous owner was, so I have no history of the amp.

 

[MrMarkIII]

I have a blue and a green stripe, so that's my experience. My opinion is your observations are normal, with a caveat about the age of the amp.
The Volume 1 is really more of an input sensitivity control. I wouldn't characterize the perceived loudness as "dropping off', but as "shelving".
I think it's the design, coupled with the way the human ear works.
Again, nobody's wrong, everybody's right, no two amps are the same, YMMV, etc.
The middle control works about the same for me as you describe. Even the manual calls it a subtle control. One factor to remember is the higher you run the Treble, the weaker the effect of the Bass and Middle controls.
I'm guessing you have a Simul-Class amp, which has a more rounded-off sound than the 60 watt or the 60/100.
I had a 60/100 blue stripe briefly, and it had amazing cleans, and it did seem like all the controls had a bit more range. I prefer the spongier response of the 15/75 Simul (25/85 in the green stripe).

 

[gummx97]

I have a blue and a green stripe, so that's my experience. My opinion is your observations are normal, with a caveat about the age of the amp.
The Volume 1 is really more of an input sensitivity control. I wouldn't characterize the perceived loudness as "dropping off', but as "shelving".
I think it's the design, coupled with the way the human ear works.
Again, nobody's wrong, everybody's right, no two amps are the same, YMMV, etc.
The middle control works about the same for me as you describe. Even the manual calls it a subtle control. One factor to remember is the higher you run the Treble, the weaker the effect of the Bass and Middle controls.
I'm guessing you have a Simul-Class amp, which has a more rounded-off sound than the 60 watt or the 60/100.
I had a 60/100 blue stripe briefly, and it had amazing cleans, and it did seem like all the controls had a bit more range. I prefer the spongier response of the 15/75 Simul (25/85 in the green stripe).

Thanks MrMarkIII for your insights. You are correct in assessing that I have a simul-class amp. I had called Mesa today and inquired about my "issues." You are right once again. I had spoken to someone in customer service named Marcus, not sure if he was the one that does those mesa videos, but nonetheless, very helpful in trying to answer my questions.

As you previously stated, all my controls are "normal" from what Mesa told me. I am just not used to this type of set up since my other amps were a Mark IV and I also currently own a triaxis, in which the triaxis seems a bit "simpler" to use and not as interactive as a Mark III.

I'll probably change the tubes later on to mesa's and be done with the amp and just use 'em....it's a heavy amp though for a combo. Thanks for your insights.