Studio 22+

[Mizzle]

Hello all,

Looks like I have a chance to pick up a Studio 22+ in great condition. Well, almost great condition.... There is one pot/knob that is broken off. The complete stem of it is snapped down to the face plate. Can still rotate it by pressing a thumb into it and twisting but it's not ideal. I have a few questions for those that have more knowledge about it than I do.

First, how long should it take to swap out for a new pot? It looks fairly compact in there and not sure what else needs to be removed stop do it.

Secondly, I called MB to ask some questions but didn't get a response back yet. I'll have to put in another call because its been a few days now but I figured some on here might know the proper part number or what I need. Seeing on line there are different lengths of pot shafts that MB uses over the years so I'm not sure about the Studio 22+.

Third, it has the volume drop issue after she warms up and is running for 15 minutes or so. It seems like it's def the effects loop because when I insert a cable in, it seems fine and no more intermittent volume drops. I've tried inserting a cable in and out numerous times to see about removing some of the ??corrosion?? But it's not working. What's the best way to clean them?

Lastly, is there anything else I should look at or inspect to be sure all is right?

Thanks all, I look forward to learning a lot from the unique world that is Mesa Boogie.

 

[Whoopysnorp]

I've had my Studio .22 open a number of times for various reasons. It's sort of a pain to get at the innards, since you have to unsolder a few wires and lift the circuit board up. On the other hand, the pots have flying leads to the PCB rather than being soldered directly (at least on mine--keep in mind it is an older model). That makes the prospect of changing one a lot less daunting. If you are comfortable with simple soldering jobs, you should be able to manage it OK.

I just popped one of the knobs of my amp, and the part of the pot shaft that protrudes from the threaded housing measured 5/8". It was a half-shaft pot (or whatever those are called). Again, YMMV to some degree. A can of contact cleaner from Radio Shack should be useful for cleaning up the issue on the effects loop, though I've never tried to remedy that particular issue myself. Good luck!

 

[Big Block]

I'd just take it to a certified Mesa tech and have em do it. Couldn't cost very much.

 

[selectortone]

As stated, you need to lift the PCB up away from the chassis before you can replace the pot, and to do this you will have to unsolder a couple of leads from the back of the PCB. Easy enough once you've done it a couple of times but it took a bit of figuring out the first time I did it.

As regards the effects loop, spray some contact cleaner on a jack plug and insert and remove it a few times. If the problem keeps coming back you'll need to replace the socket.

Enjoy your Studio 22+. I have a DC5 and a Studio 22+ and I love them both. The Studio 22+ is perfect for small gigs. I've done the Lead Gain pot mod and that makes balancing the channels a lot easier.

 

[Mizzle]

Thanks for the info everyone. I am going to bring it to the MB service center in my area. I have soldered things but its not often enough. I'd rather have it done up by someone that is more familiar with taking these amps apart and back together again.

I will get some cleaner for the jacks. I'll report later how it works out. Hey, is this something that I can do to all of the input jacks? Can I harm any by spraying some on a cable and inserting it a few times?


I looked at the tubes in it. It has Mesa EL-34's and for the pre amps reading from left to right:

elec harm 12ax7, elec harm 12ax7, mesa 12ax7-A, groove tube 12 ax7B-2, mesa 12ax7

So here is my surmise of the tone. I know with mesa boogies that the tone knobs all affect each other. I can't really get the mids to be present though. Tried both single coils and humbuckers. Seems muddy in the middle. Lack of definition if you will. I'll keep fiddling with them and the sliders.

 

[Mizzle]

So another question for some on here. The reverb unit on a 22.... It seems mild. I am used to fender reverb. I'm not looking to clone fender reverb in this amp but is there anything I can do to get a smidge closer to it? The best word I can use is that it's mild. The guy that owned it before me did have it bagged to combat the supposed reverb howling feedback that can occur in this amp.

Any info appreciated. Thanks.

 

[NunoVanBamSteen]

When was the last time you had it retubed?
My reverb was very low and had no depth, a retube cured it.

 

[Mizzle]

I will try to put a new tube in. The guy before me said it was recently retubed but I never did get an actual time frame out of him. Thanks for the advice.

 

[tonejam]

The reverb is mild because the 22+ comes with a small reverb tank. When you take the amp to a tech, ask him to install a full size tank.

 

[NunoVanBamSteen]

This is also true, but dying tubes can obfuscate things even more.

 

[Mizzle]

 

[mesaboogie6L6]

very nice!

 

[tonejam]

that's one very sexy 22+ !!!

 

[Mizzle]

Thanks. I just had the knob repaired and apparently the tubes were originals from 91 or 92. A bit microphonic said the repairman. So it has new power tubes. So now I can actually try to dial in a sound with it. Sampling a bit of which guitars sound the best through it.

One thing that has me wondering is the POP sound when engaging the OD channel. When I do it for the first time, it's a loud noticeable POP. Then I can switch back and forth with out much notice. If I stay on the clean channel for a bit, 5 minutes or more I'd say, it makes the loud POP sound. It's almost like something builds up. Could it be? That's the best way I can explain it.

 

[stokes]

Thanks. I just had the knob repaired and apparently the tubes were originals from 91 or 92. A bit microphonic said the repairman. So it has new power tubes. So now I can actually try to dial in a sound with it. Sampling a bit of which guitars sound the best through it.

One thing that has me wondering is the POP sound when engaging the OD channel. When I do it for the first time, it's a loud noticeable POP. Then I can switch back and forth with out much notice. If I stay on the clean channel for a bit, 5 minutes or more I'd say, it makes the loud POP sound. It's almost like something builds up. Could it be? That's the best way I can explain it.

Its just a cap charging and discharging,its perfectly safe and normal.

 

[McBarry]

Hope the tubes were EL-84 and not EL-34 as mentioned.. ouch....

Also these babies are notorious for getting hot inside - a fan would be a VERY welcome addition in there. FWIW, the FX jacks should be not only cleaned, but re-tensioned. Metal fatigue may well necessitate replacement too. Keep an eye on them.

The other thing to say is these boards, being mass-produced and subject to PLENTY heat over the years are very very prone to dry joints.
Any faults at this age and beyond, dry joints should be considered, especially around the power tube area..

Food for thought..
Dave

 

[himmelhund]

mesa certified tech??? Any good tech will be able to help and please don't open the thing up and work on it yourself, you might blow yourself up.

 

[Mizzle]

Well, I took it to the Mesa guy near me. I don't know a ton of people that are certified techs. I didn't want to take it to a guy that says "Yeah, I can open her up and have a whack at it."

You can see all 8 knobs on it now. Already repaired and no more volume drop outs. Now it's just a matter of dialing it in. I am just so used to a fender sound. This is a bit of a departure. I got this because my 60 and 40 watt amps are waaaay too much for what I need. I thought a 22 would be just fine. This thing screams.

 

[McBarry]

Miz, for future readers of this thread, what did he say was causing the vol dropouts?
DB

 

[Mizzle]

The drop outs were due to a dirty effects loop. A very common problem from what I've read. I was putting a small jumper plugged into the effects loop but I had him clean it properly so I didn't have to feel like I had a band aid on it.