Studio 22

[NunoVanBamSteen]

Excellent!
Thanks!
Funny thing, they said they didn't have this written out anywhere.
I wonder if they're clamping down on company 'secrets' and trying to bring more business to the service dept?

 

[&drew]

Lead Drive, Pull Deep.
That's a good addition - especially if anyone doesn't have the Graphic EQ (which can be set to switch in on the Lead channel only or always in).

In any case I would imagine Pull Deep would add more versatility.

Similar pull switches could be used on the tone stack pots to give 'Pull Bright' on the Treble pot etc. I'll have a look at the Mark series schematics to see how it's done.

 

[&drew]

Here's the Lead Drive mod I mentioned...
http://acapella.harmony-central.com/showthread.php?t=2223437

 

[mxr2000]

Lead Drive, Pull Deep.
That's a good addition - especially if anyone doesn't have the Graphic EQ (which can be set to switch in on the Lead channel only or always in).

In any case I would imagine Pull Deep would add more versatility.

Similar pull switches could be used on the tone stack pots to give 'Pull Bright' on the Treble pot etc. I'll have a look at the Mark series schematics to see how it's done.

I like this ideas own some of this units now an love it but wish more versatility on tones. i think the final result would be like a Mini mark series amp and fact i like more this mod's can be done to .50+ caliber amps too keep the info coming 8)

 

[NunoVanBamSteen]

the whole point of this amp was to be a low cost solution for those who wanted to get into a Mesa Boogie without needing a loan or a co-signer for said loan. These are Low dollar High bang for the buck amps. You ca neither have great tone or a lot of features but one will suffer if you keep the costs low.

Thanks for all the above info.

 

[&drew]

I agree Nuno - the Studio .22 is beautifully simple & was Mesa's first 'hit single' - as their marketing said in the 80's. The versatility and power of the later Mark series was sacrificed for lower cost - but the build quality & core tones remained high quality.

Mods...
• Lead Master to balance mode volumes and Lead Drive to add overdrive versatility
• Pull Deep on Lead Drive pot for fatter lead tone (¿or Pull Deep on Mid control? - active on both Lead & Rhythm modes)
• Pull Bright on Treble pot

...any other suggestions anyone?

 

[mxr2000]

I agree Nuno - the Studio .22 is beautifully simple & was Mesa's first 'hit single' - as their marketing said in the 80's. The versatility and power of the later Mark series was sacrificed for lower cost - but the build quality & core tones remained high quality.

Mods...
• Lead Master to balance mode volumes and Lead Drive to add overdrive versatility
• Pull Deep on Lead Drive pot for fatter lead tone (¿or Pull Deep on Mid control? - active on both Lead & Rhythm modes)
• Pull Bright on Treble pot

...any other suggestions anyone?

It would be fantastic to see it here with the complete info for everybody benefit, you think this will add more sustain to this amps? the fat lead tone is something that i would love to do on my amp i think it would be very handy late at night when i play at a very low volume. if you have already all the info from this mods could you be kind to post them on this thread? Thanks

 

[&drew]

:idea: mxr - we are thinking along the same lines :wink: . I'll do what I can...ANYONE - PLEASE HELP if you can.
We should search the Forum for info on all the mods then post them again. Should we make a special forum with all the mods set out clearly? What's the consensus?
The mods are scattered across this forum in bits & pieces - as each person tries to gather what they need to do the mods. :?

 

[NunoVanBamSteen]

I'm new to this forum, but is there a file area where we can just post up what we have?
I have schematics of the Triaxis Mods (regulator upgrades) and general svc manuals and schemats for the amps I've owned.
Can we warehouse that someplace here without getting in to trouble?

 

[&drew]

nuno - I'm fairly new here too - have you searched for posts on your other amps? Maybe post your info there?

is there a file area where we can just post up what we have

Like a 'library of mods & schematics' organised by amp? That would be good.
As a start we could gather all the .22 mods & post them on a main thread, such as this one.

mxr - as for the 'fat tone' & sustain, 'selectortone' has done it. I wonder what it sounds like?
The new cap rolls off even more of the high frequencies than Mesa have decided upon in their original design.

 

[mxr2000]

nuno - I'm fairly new here too - have you searched for posts on your other amps? Maybe post your info there?

is there a file area where we can just post up what we have

Like a 'library of mods & schematics' organised by amp? That would be good.
As a start we could gather all the .22 mods & post them on a main thread, such as this one.

mxr - as for the 'fat tone' & sustain, 'selectortone' has done it. I wonder what it sounds like?
The new cap rolls off even more of the high frequencies than Mesa have decided upon in their original design.

Agree.. ^_^

 

[selectortone]

The new cap rolls off even more of the high frequencies than Mesa have decided upon in their original design.

Actually it's the other way round. C5 is an interstage coupling cap that joins V1 to V2. The purpose of a coupling cap is to block DC while allowing AC (your guitar signal) to pass. Small caps only allow the higher frequencies through. The bigger the cap the broader the frequency band. So my new cap allows more lower frequencies through than the standard cap does. (Forgive me if I'm preaching to the choir here...)

The mod is very easy to do. Since the total value of capacitors in parallel is the sum of the capacitance I just tacked the new .022uf cap onto the top of the PC Board across the existing cap - so now C5 is effectively (.022uf + .001uf) .023uf. You don't need to remove the PCB which on the Studio 22+ is a pain in the ass.

Notes:

1. Since this is a coupling cap and is connected to the B+ it needs to be the correct voltage rating. I used an orange drop rated at 450v.

2. Putting this mod on a push pull would be very easy; just connect the new cap in series with the switch. It would be good practise to insert the pot switch AFTER the cap, not before, otherwise you'll have B+ on your switch, which may not be rated for it.

How does it sound? Well.....fatter . The standard cap sounds thin to me and for my purposes there is too much of a change in tone between modes. I wanted my lead mode to sound tonally like my normal mode, just with more overdrive. However, YMMV - I can understand Mesa's thinking with the standard small cap; if you want the classic Boogie creamy saturated overdrive sound my fat mod will probably sound too mushy.

DISCLAIMER: modding tube amps is dangerous unless you know what you're doing and can be fatal. I take no responsiblity for the veracity of the above.

 

[&drew]

Thanks for the correction (always welcome) and the time taken to explain.
This is interesting to me. I used to build amps when a teen but let it slip.
25 years later, planning some amp mods has got me interested in how amps work.
To do is to know - but maybe I should read a few good books or go on a course...
..so I don't cause you knowledgeable guys too much grief with my suppositions....

 

[Tacoiardul]

is it just mine or studio 22's are kinda fragile?i like to think that i take extra care with it ,but last night at my gig i had some serious problems with it...the clean channel had volume issues,as is loud then almost silent...could it be the v1 tube?the clean channel tube?the power amp tube? i wish they were more reliable ...

 

[&drew]

hiya Tacoiardul

If the problem is on the 'Rhythm' mode then it can't be V1 - as V1's enormous gain is only switched in for Lead mode.

So likely to be V2 or V3 but could be any other. View your valves when powered up. All look the same colours? Maybe a clue. Any microphonic?

Best to get a known good 12ax7 and in turn switch it for V2 to V5 starting with V2.

[Easiest to do by taking the chassis out of the cabinet. For novices, BE CAREFUL and get help if uncertain what you're doing. Power up with guitar attached. In Standby mode swop valve, power up to play mode and check for any improvement in problem. DO NOT TOUCH ANYTHING WHILE POWERED UP - even when switched off valve amps can still be a killer - the large caps hold a charge.]

The manuals for other boogies have good instructions how to do all this. See Mesa website.

Preamp valves can be intermittently operating. Faulty ones tend to give odd noise/tone or not work at all.
Power valves tend to wear out slowly, gradually dulling the tone and volume or suddenly blow.

As you may have read I've had my studio .22 since '87ish and it's had the usual problems for this old amp:

Design fault: its R121 in the footswitch circuit needs to be upgraded to 1kohm 2watt - mine caused all sorts of problems before it predictably blew; bad pops when mode switching.

Wear & tear: clean inside of pots and (if you have it) Graphic sliders with something like Faderlube as dirt/oxidation on old amps can cause poor tone, volume drop outs and noise.

Clean all contacts with something like Deoxit. Socket contacts, valve holders, reverb plugs/sockets & switch contacts etc.
The (signal path!) Send/Return socket contacts can easily get dirty & oxidised. I'm considering an FX Loop BYPASS switch to take the switching sockets out of the circuit when no FX Loop used.

I hope this helps.

 

[Tacoiardul]

thanx,i was thinking about v2 or v3 to for some reason i wrote v1 i have only tried the clean channel since i did have the footswitch with me,but prior to this problem the amp had abnormal noise when switching to the lead mode.i'll try some new tubes for the preamp and see then.i blame the transportation for these problems...damn it..the preamp tubes should last longer than 6 months..

 

[NunoVanBamSteen]

You didn't use Groove tubes, did you?
I'm a huge opponent of GT. Had a NASTY batch once and it was only because I desperately needed a tube replacement in a pinch and that was all Guitar Center had. I tried to return them, no dice.
I sent them back to GT for a replacement. I talked to the customer support and he essentially blew up their own spot, saying that they barely test them, just to see if they light up and off they go. Total scam.


Stick with a straight brand of Sovtek, EH, JJ, whatever.
GT, Ruby and Mesa just re-brand the main manufacturers.( any others I'm missing?)

Another batch of GT's (Bad out of box) had a plate to grid short, blew out the wiring of the amp I was working on. (5150)
I had to rewire the amp and replace the tubes.

Most useful thread ever? :mrgreen:
Happy I found the boogie board!

 

[&drew]

I have only tried the clean channel since i did have the footswitch with me,but prior to this problem the amp had abnormal noise when switching to the lead mode.

Could still be a 12ax7 problem but this sounds like you may also need to upgrade R121 as mentioned. If not done it will blow eventually. My old R121 exploded and burnt the circuit board. MESA recommend upgrade.

If Foot Switch lost - Mesa manual says any cable can be used and short to chassis earth (eg metal switch toggle or input socket edges) to switch mode to Lead.

Good points NunoVanBamSteen

I've also had bad experience with GT.

There appear to be several visible variations on the actual internal design of 12ax7's depending on manufacturer's factory.
They are then rebranded for each retailer, sometimes checked for quality parameters before pass - such as MESA say they do.
Apparently they reject a large proportion and resell them to GT!

 

[Tacoiardul]

the tubes are all Mesa original tubes...i'll look into the possibilty of the upgrade,thanks for the advice

 

[NunoVanBamSteen]

GTs have their lil rating system that just puts a letter after the type of tube to designate which factory it came from, C+Chinese, R=Russian (Sovtek) etc.
In some ways a smart marketing method, but in other ways, their QC sucks.
In any good business, a lemon is likely to sneak by, how is it BOTH times I've ever used GT, I've gotten those lemons?
I'm thinking they have a lemonade stand out back.
Fender owns the Groove Tubes name, now, btw.
Maybe things will improve, but honestly, why buy theirs when I can buy a JJ which is rated and matched at Eurotubes at no major cost to me?
Long live Eurotubes!