Interesting "issues" with my MkV

[pj1967]

I've had my MkV since Oct and been pretty happy so for. I haven't been able to play with it for several weeks, so when I finally got a chance last night, I noticed some issues:

1) clean channel breaks up (gritty) at low master volume (set 3 o'clock), when set at noon or higher, it's clear.
2) when switching channels, reverb cuts out and swells back in after a couple seconds.
3) ch3 (not using extreme mode) is a good bit louder than the other channels. I have heard the extreme channel is louder, but I'm experiencing this in the other modes.

All channels are using the active EQ, and issues occur with or without FX loop engaged.

Any thoughts?

--PJ

PS..I've got a vertical 2x12 rectifier cab on the way! Hopefully, it comes in before my next gig!

 

[phyrexia]

2 & 3 are normal.

1 is odd.

 

[mejoshee]

2 & 3 are normal.

1 is odd.

not really, depending on the pickups. if the amp is getting a lot of signal on the input, with a low master volume setting, you have low headroom. try turning the gain down pretty far. i keep mine at about 9-10 and just keep the master up high.

in a tube amp, there is no such thing as 0 distortion. there is always a certain percent present. usually, when it's a clean amp we think it is 100% un-distorted, but really it's just an imperceptably low level.

another thing is your power switch setting--variac is less clean in headroom. and your global master volume plays a role as well.

as for 2, it's usually cause you're using slightly different reverb settings and because the reverb circuit produces a different feel depending on the channel you use it on. it's more apparent there is reverb when using a cleaner setting.

ch 3 is a gain monster on all modes. it's ok for it to be louder because otherwise how else are you going to annoy the neighbors? 8)

 

[pj1967]

Thanks for the replies...

I figured 1) and 3) were "normal", but 2) seemed weird...mejoshee's explanation sounds reasonable though. I also figured that 1) was related to "headroom", but since I've not experienced it so profoundly on other amps, I thought I'd ask.

Incidentally, like most amps I've had, once you dial up the master volume to 10 o'clock and beyond, you can almost feel the amp take a deep breath and "open up." It's a nice feeling

 

[mejoshee]

Thanks for the replies...

I figured 1) and 3) were "normal", but 2) seemed weird...mejoshee's explanation sounds reasonable though. I also figured that 1) was related to "headroom", but since I've not experienced it so profoundly on other amps, I thought I'd ask.

Incidentally, like most amps I've had, once you dial up the master volume to 10 o'clock and beyond, you can almost feel the amp take a deep breath and "open up." It's a nice feeling

mesa's have so many gain stages, that's why. master volume functionality is sometimes that way if it is preamp distortion before power amp distortion. it's still a little fizzy, which is why, in the end, the amp still can sound like a$$ if you spend all your time on the lowest power settings. feel is lost, frequency response is screwed up. but you can open it up! (and you should, if at all possible).

there are others who claim power scaling, which is a linear and tracked reduction in the actual high-voltage taps (the headroom). that is actually, in theory, a better method, but requires a little more power electronics knowledge and circuit design work.

the funny thing is, for how advanced we think some of the modern amps are these days, they're just the same old circuits but finally all put together in one package. think about it like how marshall went from non-master volume (the plexi-type) to the master volume (jcm-type).

anyway, my $0.02

oh, and i don't even bother using the verb on ch 3. if i need that, i'll mix in stuff in the fx loop from my m3000.

 

[MrMarkIII]

#1 is normal.
In a Mesa manual, I forget which one, it explained that at very low settings of the master volume, it's harder to keep the clean channel clean because of electronic limitations (maybe crosstalk?). (I'm looking, I'm looking! :lol: )
So are #2 and #3. At least, Mesa says they're normal in the manual .

 

[SteveO]

The reverb delay is normal, Mesas does this so that there isn't spillover when switching between channels, especially going from dirty to clean. My MV does it, and the Roadster I had did it, too.