Studio.22+ questions nad gutshots

[Mrmot]

Hey guys, I've got a few questions about my Studio.22+.. first of all, where's the serial number??? I'm puzzled. Here's a pic from the back of the amp where it should be:

They put the "Mesa/Boogie Caliber +" sticker in the lower left corner to cover the hole which is i guess for "eq select" (mine doesn't have the onboard eq)


Also, it seems like the owner(s) before me changed two pots, the "lead master" one and "middle", on the front panel you can clearly see that the lead master knob is not the same as the other knobs, and the "middle" knob moves a lot easier(too easy, i would say) than the other pots.

Here's how the pots look from the inside:

you can clearly see that the two pots differ from others..
the writings on bass, treble, master and presence pots are:
591048 137/8924 ROC

on the reverb:
591050 137/8930 ROC

on the volume:
591047 137/8924 ROC

on the smaller "middle" pot it says:
591378 137/9009 ROC

and on the "lead master" pot it doesn't say anything.
So, what do you think, should I change these pots to the originals (if i can find them)?


Here are some more random inside pics...

I guess that's the production date:

a place for the graphic eq:

...

trafos:

and finally...

 

[Monsta-Tone]

Mine has the serial # stamped into the chassis & back face plate right after the 'FP', between the Speaker jacks & the FX Loop jacks.

I think that mine is newer than yours though, maybe you have a really early production one.


Also, the sticker that you have covers the place where the Ground switch is on mine.



As for the pots, if they work, I don't think that you should really worry about them. If they break, then you might want to find CTS pots to replace them with.

 

[tommyhawk13]

It's the second version of the Studio combo. It's got 1 power tube, right?
I wouldn't try to add an eq to the amp, tempting as it may be. There are 5 band eq pedals & tons of rack eq's out there.
These are pretty sweet amps.

 

[RR]

It's the second version of the Studio combo. It's got 1 power tube, right?

I think they always came with a pair of EL84s.

What's peculiar, like you mentioned Mrmot Studio Plus and it does not have a EQ.

Seems like the "Lead Master" potentiometer since it has a SPST switch in back acts like a channel switcher from clean to lead if you happened to misplace your footswitch. But I'm guessing. But you probably know that already.

 

[Monsta-Tone]

What's peculiar, like you mentioned Mrmot Studio Plus and it does not have a EQ.

I asked Mesa about this when I 1st got mine, which has the EQ. They told me that the + had a beefier power supply and the addition of the Lead Master, and that some of them came with the EQ, but not all of them.


This amp has 2 power tubes, you can see them toward the back of the board.

I don't think that the Studio 22 ever had just one power tube, it would not be 22 watts if that were the case.



As for the Lead Master pot, I don't see a switch on the back, only the contacts for the pot itself. These amps don't have a switch for channel switching on the chassis, you have to use the footswitch or a jumpered cable.

The EQ switch is on the front, right next to the Standby.

The switch on the back in the lower left hand side of the chassis is, or should have been, the Ground switch.

 

[RR]

Thanks Monsta-Tone clearing some stuff I speculated.

Do you have any guess why the "Lead Master" pot has that SPST (seems like a "push / pull" pot)? I would guess it would be a switch for channel switching but like you mentioned, a simple jumper would work but curious why the push / pull pot if it is one of those type of pot or maybe an Off / On[?]

 

[Monsta-Tone]

Mine doesn't have the push-pull pot on the Lead Master, but it's not a bad idea, just incase you don't have the footswitch with you at the time.

I think that the one in MrMot's amp is just a pot that looks like it has a push-pull switch on it. I only see 2 wires on it. If it were a push-pull, it would need more wires.

 

[Mrmot]

Mine has the serial # stamped into the chassis & back face plate right after the 'FP', between the Speaker jacks & the FX Loop jacks.

goddamn, where's the serial on mine?! I looked inside the chassis and it's nowhere to be found :?:

I think that mine is newer than yours though, maybe you have a really early production one.

Well, i can't tell if yours is newer or not but i know that mine isn't an early one, early Studios had metal switches one the front (power, standby, eq) while newer ones have the plastic switches. Also, the date on the chassis (02/27/90) is written on the "american" way so I'm guessing that it's the production date and not some tech's repair date since this is the european version.

Also, the sticker that you have covers the place where the Ground switch is on mine.

why doesn't mine have the ground switch? another puzzle :?: Since this was planned for the european market, maybe we have "better" electricity here so it doesn't need one? :lol: j/k

Seems like the "Lead Master" potentiometer since it has a SPST switch in back acts like a channel switcher from clean to lead if you happened to misplace your footswitch. But I'm guessing. But you probably know that already.

no, but i think that Studio .50 and Studio Pre have this feature, to be able to switch channels via the lead master push-pull knob, but studio.22+ never has(had) this AFAIK

I asked Mesa about this when I 1st got mine, which has the EQ. They told me that the + had a beefier power supply and the addition of the Lead Master, and that some of them came with the EQ, but not all of them.

Yes, the "+" determines if the amp has the "lead master", both "+" and non+ version are available with and without the onboard eq. I also heard that the "+" version have an upgraded fx-loop, but i can't verify that.

It's the second version of the Studio combo. It's got 1 power tube, right?
I wouldn't try to add an eq to the amp, tempting as it may be. There are 5 band eq pedals & tons of rack eq's out there.
These are pretty sweet amps.

push-pull amps always have a pair number of powertubes while single-ended amps can have only one power-tube (but can also have more). Push-pull amps can be Class A, Class A/B (most common) and class B, while single-ended amps are always Class A. Here's a cool little link about that

I'm using mine with the boss ge-7 graphic eq in the loop and it works great!

 

[Monsta-Tone]

Maybe yours will be worth more since they never printed the serial # on it. In America, if a coin is misprinted or double printed, it is worth much, much more than the face value.

Mine has the plastic switches too.

why doesn't mine have the ground switch? another puzzle Since this was planned for the european market, maybe we have "better" electricity here so it doesn't need one? j/k

:lol: :lol: I think that I read somewhere about this. I am pretty sure that either Europe didn't need them because they had 220 volts, or that it was illegal there before it was illegal here.


If it really bothers you about the pots, you can always order some replacements. If they work well and feel like they are fairly decent quality, you could always leave them there.


Your's is a one-of-a-kind.

 

[Mrmot]

Maybe yours will be worth more since they never printed the serial # on it. In America, if a coin is misprinted or double printed, it is worth much, much more than the face value.

Mine has the plastic switches too.

That thought crossed my mind too

:lol: :lol: I think that I read somewhere about this. I am pretty sure that either Europe didn't need them because they had 220 volts, or that it was illegal there before it was illegal here.

illegal? why?

Your's is a one-of-a-kind.

you can bet your "i_have_a_mass_produced_boogie_like_others_have" ***!

 

[tommyhawk13]

It's the second version of the Studio combo. It's got 1 power tube, right?

I think they always came with a pair of EL84s.

What's peculiar, like you mentioned Mrmot Studio Plus and it does not have a EQ.

Seems like the "Lead Master" potentiometer since it has a SPST switch in back acts like a channel switcher from clean to lead if you happened to misplace your footswitch. But I'm guessing. But you probably know that already.

I was thinking since the .50 cal went to 2 6l6's...
Doh!

 

[ytse_jam]

Mrmot, when I got my Studio Preamp, I immediately noticed the MIDDLE pot was way looser than the others. I thought it could have been damaged but when I had the chance to try another Studio Pre, even that one had the loose MIDDLE pot, so I'm assuming it is a different pot coming stock. Is your MID pot looser than the others too? Maybe it is stock: take a look at the pic of my Studio Pre I took. It isn't the best pic to notice the different pot, but it's the only one I already have. You can see an outstanding little part of all the other pots except for the MIDDLE one (which is the fourth one from right after the graphic eq. I think the smaller pot could come stock.

 

[Daevid]

I opened up my Studio 22+ last night, mainly to have a look at the Caps (they have not been changed since the amp was first made in 1992) and to give the board a quick dust and the pots a quick blast with contact cleaner...

All the pots look to be of the same size and type, though the Middle does seem to be a lot looser (as is one of the EL84 sockets)... the Serial Number is on the base of the Chassis and i have a small plate over the area where the Ground Lift Switch would go (on the other side you can see the rectangular hole)...

A couple of thoughts though, can you still get the white plastic suspension bits for the PCB/ Chassis? and has anyone found a better way of securing the EL84s rather than that plate secured by plastic bits (one of mine is now broken due to heat, age and haste in trying to open it to put in new valves pre gig!

 

[Mrmot]

Mrmot, when I got my Studio Preamp, I immediately noticed the MIDDLE pot was way looser than the others. I thought it could have been damaged but when I had the chance to try another Studio Pre, even that one had the loose MIDDLE pot, so I'm assuming it is a different pot coming stock. Is your MID pot looser than the others too? Maybe it is stock: take a look at the pic of my Studio Pre I took. It isn't the best pic to notice the different pot, but it's the only one I already have. You can see an outstanding little part of all the other pots except for the MIDDLE one (which is the fourth one from right after the graphic eq. I think the smaller pot could come stock.

so i guess that's stock cause the mid pot on my studio is a LOT looser than the others! Thanks man, that's one mystery solved!

A couple of thoughts though, can you still get the white plastic suspension bits for the PCB/ Chassis? and has anyone found a better way of securing the EL84s rather than that plate secured by plastic bits (one of mine is now broken due to heat, age and haste in trying to open it to put in new valves pre gig!

I really dunno, mine is still in good shape.. maybe you could make something by yourself?