Looking for Mark IV Lead Gain Pull Fat pots.

[James Lugo]

Hey so I bought a Rev A Mark IV last week and the Lead Gain Pull Fat pot broke instantly. After chatting with Mesa they don’t have any left and are no longer making them. Does anyone know where to find one or a replacement? Does anyone know the part number?

My tech was able to use a non pull pot and mod it to in ‘pull’ mode. I ordered a couple of pull pots from Mesa for R1 and R2 but they said they won’t fit in lead gain. They said I can use them in R2 and move that pot to Lead Gain but my tech didn’t seem totally into that. I really would love to buy a few of these Lead Gain Pull Fat pots.

Thanks

 

[kmanick]

I'm in the same boat, the plastic stem on mine broke. I was able to super glue it back in and it works but it's stuck in pulled , and
if I wiggle it the gains cuts in and out. Mesa support has not been much help, they don't carry them any longer.

 

[kmanick]

so my IV is with my amp tech right now , this is what the pot we need looks like (it's the top one) it's a flat thinner pot than what is available with a push/pull these days.
so I did get this pot and they assured me it would fit
https://amprepairparts.com/pvcps.htm
or this one
https://www.amazon.com/dp/B00E1N3K54?psc=1&ref=ppx_yo2ov_dt_b_product_details
( I bought both just in case)
Mesa told me it wouldn't fit. I get it to may tech and we pull the chassis. It doesn't fit , there is no room behind the pot to the PCP board
but Mesa did say, and my tech confirmed that there is plenty of room behind the Clean gain pot and the R2 gain pot. They all use the same pot as the lead
so he's just going to swap the R2 pot with the lead pot and install one of these new pots to R2. (reading your post you already know this)
At least this way I still have pull pots in all 3 positions.

I should have it back either tomorrow (Friday) or Saturday
I'll update this post once I get it back
Nick
It's very disturbing that no one makes these pots any longer, such an Iconic amp and we have no parts for it?

 

[user 41014]

What is the part # on the bad pots? It looks like it has a split shaft.

There are CTS pots for the older Marks for which Mike still has one value and uses that frame to swap in guts by hand for the values he needs. That isn't enough demand for CTS to remake pots.

Given the scarcity I would save those pots with broken shafts since you may be able to rebuild it with a donor shaft.

 

[James Lugo]

The problem is the main pull for high gain is in a spot on the circuit where there is no room for the larger pots. After dealing with this for a couple of weeks I was so disappointed with dealing with Mesa and the local tech I dumped the amp. I really liked the way the Mark IV felt and sounded but I don’t need anymore pain in the ass gear in my studio. With that said there’s one for sale on Marketplace. It’s original owner and never left the house. Looks new. Ughhh. We’ll see.

 

[Henz]

The problem is the main pull for high gain is in a spot on the circuit where there is no room for the larger pots. After dealing with this for a couple of weeks I was so disappointed with dealing with Mesa and the local tech I dumped the amp. I really liked the way the Mark IV felt and sounded but I don’t need anymore pain in the *** gear in my studio. With that said there’s one for sale on Marketplace. It’s original owner and never left the house. Looks new. Ughhh. We’ll see.

That sux! It really shud be an relatively easy fix. Can't ya rebuild the pot? Where can I find info on this sale? Combo? Head?

 

[kmanick]

What is the part # on the bad pots? It looks like it has a split shaft.

There are CTS pots for the older Marks for which Mike still has one value and uses that frame to swap in guts by hand for the values he needs. That isn't enough demand for CTS to remake pots.

Given the scarcity I would save those pots with broken shafts since you may be able to rebuild it with a donor shaft.

this is the pot that is on the Mesa site but it doesn't look like the one in the picture, it's a solid shaft.
I'll get the broken one back from my amp tech but I don't know who would fix something like this. (I'll ask him if he can do it but I doubt he's interested in fixing pots)
I should be ok moving forward, but if the Drive pot ever goes then what? I'll have to see if there is more room over there to fit one of the current pots
https://store.mesaboogie.com/products/pot-591842-280-s-1m-audio-with-pull-switch.html

 

[James Lugo]

this is the pot that is on the Mesa site but it doesn't look like the one in the picture, it's a solid shaft.
I'll get the broken one back from my amp tech but I don't know who would fix something like this. (I'll ask him if he can do it but I doubt he's interested in fixing pots)
I should be ok moving forward, but if the Drive pot ever goes then what? I'll have to see if there is more room over there to fit one of the current pots
https://store.mesaboogie.com/products/pot-591842-280-s-1m-audio-with-pull-switch.html

That’s what my tech did. He moves the clean pull down to gain pull fat and used the cts pot in the clean.

 

[user 41014]

That pot does not look the same. A pull switch should have 2 extra lugs like the mesa link.

There are other 591xxx Mesa pots available that are 280/s. They likely have the same shaft. If you pull the original pot apart you might be able to swap the shaft.

If 591842 is the right pot I don't think the one in the pic is original. I can't see how it is a pull switch. It sounds like you're saying there isn't room tho so I'll need to see if I have pics of mine or pull the chassis to see how tight it is.

 

[James Lugo]

That pot does not look the same. A pull switch should have 2 extra lugs like the mesa link.

There are other 591xxx Mesa pots available that are 280/s. They likely have the same shaft. If you pull the original pot apart you might be able to swap the shaft.

If 591842 is the right pot I don't think the one in the pic is original. I can't see how it is a pull switch. It sounds like you're saying there isn't room tho so I'll need to see if I have pics of mine or pull the chassis to see how tight it is.

That’s it the pull fat gain is somehow right up against something in the chassis. But you can get the larger CTS and swap around.

 

[kmanick]

So I got my Mark IV back yesterday from my tech. he swapped the R2 lead pot with the one that was broken (the lead gain pot). put the new one in R2 and the R2 pot in the lead gain position. He also put in a new power chard(attached) as the one on there had no ground pin on it, and replaced the fan power chord. checked all the caps to see if any were broken or leaking---- all good. Sounds like I have more gain in there now, the pot that broke was cutting in and out so my gain levels were constantly going up and down.
I have a NOS Mullard Blackburn in V1 a JJ in V2 a NOS RFT in V3, a JJ in V4 and a Sovtek LPS in the PI. Thing sounds like a monster now, I can't believe how loud this freaking thing is, RFT's are great in the lead slot. I had one in V4 too but the JJ actually sounds better. I just took possession of an Amperex bugle boy, a tungstram and a GE black long plate. I'm dying to mess around with them but it sounds so good as is I'm going leave it for a while.
Tom at Aztech Electronics in Watertown did the work (he's done work for me before on Marshalls and Peaveys) Mesa highly recommends them, but he ain't cheap , $100 an hour on the bench, but he turned it around for me in 4 days (and his shop is wall to wall amps) he was working on a Mark III when I picked up my IV,
so anyone one in the Boston area that needs an amp Tech, IMO he's the guy (very sarcastic sense of humor too)
Nick

 

[drahcirgnildoc]

I have a Mark IV and I think all of the push-pull pot shafts apart from the ones on the Presence controls have snapped after very minor knocks - annoys me so much that vulnerable parts on such an expensive amps are plastic. I managed to drill, pin and glue mine, but the Lead Fat switch was destroyed, so I ward-wired it ON (I never use it off anyway).

I've kinda retired my Mark IV as it is waaaayyyy too loud for the venues I play (I got an EVH 50W and it's perfect) and my Studio Preamp covers everything else.