Mk-IV Volume knob is very touchy

The main volume knob on my Mk-IV is extremely touchy. It is hard to keep the volume low. I usually have the master at 1-1/2 because if I go any higher the amp gets extremely load. I've changed the volume pot and it didn't make any difference. I've been using my channel masters to control the overall volume but I noticed that my effects were being over-driven with the individuals turned up to 5 or 6. Please let my know what you think?

Thanks!

Chuck

Sounds about right. That how mine acts also. I just assumed that how the Mark IVs were.

Sounds like mine. You can turn the channel masters down to 2 or 3 and it will make the main output knob less touchy. I like the channel masters run around 5 or so (makes the amp sound more raw, less smooth to my ears - I think you're hitting the output tubes harder when you turn up the channel masters) but if that's overdriving effects in the loop you should turn them down. I sometimes run a rack reverb in the loop and it has individual input and output level controls so I can even things out and not overdrive the effects unit.

It's a feature, not a bug

I learned on my Subway Rocket way back when to turn the volume pot very carefully by kind of 'smudging' my thumb to get it *just right*. Anything below 1.1 was manageable, anything above 1.1 was firmly in the NSFN (not safe for neighbours) category. It's a bit like the biting point of a clutch.

Same deal with the various Marks I've had since (including a IV-B). Try pushing your thumb down with half the pad on the skirt of the pot and half on the chassis and turning very slowly.

Same with mine. I have to lightly tap the volume knob hoping it turns a hair.

Anyone know if there is a remedy to make it work a little better?

Turn the channel master down.

You guys crack me up - mine does the same thing and you're all describing how I have to finesse the master volume

And yep - 1.5 sounds about right even for church practice volume. It's a loud little bugger

In jam (we are admittedly a fairly loud five piece) I run my master volume on the high side of almost three. In the lower regions, for less aggressive playing, I also find the knon very sensitive. You're running a 85 watt amp, it's the nature of the beast. Turn down the channel masters a bit, run it in tweed, triode, and class a modes. That'll lower the overall output. Won't make the knob any less jumpy, but it will make the beast slightly easier to wrangle. If it's really bothering you, but a volume pedal in the fx loop and dial it down.

Or buy a mark v mini.

I'm pretty sure you can replace the volume pot with a less touchy taper.

What about an audio taper pot? Has anybody tried that? I was going to see if Mesa would install one when I send my Mk IV in for service.

My mark iii was the same until the volume pot was renovated. Spraying deoxit might help if your are lucky. I removed the whole pot: dissembled, cleaned and retensioned the wiper. A really awkward job to get the pot in/out. Depends how much it bothers you.