studio 22+ boogie beginner

[bamyasi]

hi,

I just got one of these amps and I am having a problem with the lead channel.

I can get sound from the lead channel but it doesn't sound distorted, even when I am trying the sample settings in the manual I downloaded.

At the back there are 2 rows of tubes. Looking at it from the back of the amp there are 2 in the first row and 5 in the back row.

The middle one in the back row appears to be glowing more orange than the others (which only have a small amount of glow).

I guess this problem could have something to do with the tube but as I don't know much about them, I just wondered if this is an indicator of a more serious problem, or is this quite normal?

Thanks

p.s I have ordered a new tube but do not have any to test it out.

 

[texmexboogie]

Ok this very well can be a preamp tube problem and the easiest to fix. If you don't have a extra 12AX7 remove your reverb tube as your spare. Don't worry it won't hurt your amp your reverb just will not work. As you are looking at the back of the amp V1 is the small tube to your right and V2 is next and so on. Your not going to check the power tubes so you can just leave the big tubes alone. Now replace The V1 and check your over drive channel. Still no overdrive? Put the original V1 tube back and move on to to V2 then V3. V5 is your driver tube and if this was the problem both channels would not work. Hope this helps

 

[texmexboogie]

BTW the reverb tube is V4

 

[RR]

Can we assume your "footswitched" to lead channel?

I say this because without a footswitch, the Studio .22 is in the rhythm (clean) mode.

A friend of mine was at a guitar shop and some customer was trying out a used Studio .22 and since the store was not familiar with Studio .22, the customer put all the gains, volumes to 10 and claimed he could not get a distorted tone.

I asked my friend, was the channel footswitch intact. My friend claimed there was no footswitch. :?

If you don't have a footswitch then get a 1/4" phone plug and ground the hot to the ground, that will put you in "Lead" mode.

 

[texmexboogie]

Thanks, good point. I just assumed he had a footswitch.

 

[bamyasi]

Hi,

thankyou for your responses and advice.

btw, yes I am using a footswitch to change channels.

ok, looking from the back of the amp, I have T X T T T, where X is empty (V4?).

All seem to look ok but I still have the same problem. when I change from rhythm to lead there is a sound like a "sharp whoosh", and then it just remains clean, with some rattle.

I am testing the lead channel with these settings:

vol 10 mas 2 lead mas 3 tre 9 bas 4 mid 4 rev 0 pres 8

Feeling a bit worried! if you have any more suggestions they would be greatly appreciated.

 

[RR]

...ok, looking from the back of the amp, I have T X T T T, where X is empty (V4?).

Is the "X" a tube socket with no tube or is it just a tube socket hole that's plugged up? If its an empty tube socket, then it needs a tube, likely a 12AX7. Report back if its an empty tube socket.

Now if its just a hole that was plugged up, then likely that just chassis with an extra hole from previous MESA Boogie line chassis. Now if that's the case then:

All seem to look ok but I still have the same problem. when I change from rhythm to lead there is a sound like a "sharp whoosh", and then it just remains clean, with some rattle.

I'm not sure, but you might have a faulty footswitch. Try this, leave the footswitch cable in, but remove the footswitch. Jump a wire from the tip of the 1/4" phone plug to its sleeve. This should put you in the lead channel mode.

I am testing the lead channel with these settings:

vol 10 mas 2 lead mas 3 tre 9 bas 4 mid 4 rev 0 pres 8

I think you have an earlier Studio .22, no "+". Studio .22+ has three volumes.

 

[bamyasi]

Is the "X" a tube socket with no tube or is it just a tube socket hole that's plugged up?

A tube socket with no tube. I pulled out the tube that was in there to put in the next socket along to the right.

I think you have an earlier Studio .22, no "+". Studio .22+ has three volumes.

I hope not, cos it says .22+ on the front!

 

[RR]

I think you have an earlier Studio .22, no "+". Studio .22+ has three volumes.

I hope not, cos it says .22+ on the front!

You are correct, I misread your post "Volume, Master, Lead Master".

All seem to look ok but I still have the same problem. when I change from rhythm to lead there is a sound like a "sharp whoosh", and then it just remains clean, with some rattle.

So basically you remain in the 'clean' channel[?] when you step on the footswitch regardless. It might be a fault Carling footswitch even if your LED is glowing but I'm not certain. They do go out on you.

Did you try grounding the channel switching cable?

 

[texmexboogie]

Without getting into the guts of the amp there is only two easy tests as mentioned above. Faulty footswitch. Get a guitar or speaker cord, not the one that came with the amp, and put it in the amp's footswitch jack. the one below input, and ground the tip good to the chassis. No OD channel it's not the footswitch.

A 12AX7 basicly is two tubes in one. One side can work and the other can be completely dead. That's is why it is called a dual triiode tube. Again, V4 is your reverb tube and if the reverb is working it is good and use it in the tests. The amp will function fine without the tube just minus your reverb. V1-V2-V3-V5 always must have a tube in the sockets for the amp to work. V4 can be empty. If this simple test can't resolve it you may have to take it to a tech. Hope this helps

 

[bamyasi]

thanks, unfortunately I will have to wait until tomorrow to try it.

Get a guitar or speaker cord, not the one that came with the amp, and put it in the amp's footswitch jack. the one below input, and ground the tip good to the chassis

does that mean touch the other end of the cord to the metal part at the back of the amp and keep it there? :shock:

 

[texmexboogie]

Yes

 

[bamyasi]

I put a normal guitar cord in the footswitch socket and the other end against a screw in the handle. Putting it against the chassis didn't seem to have an effect.

It had a similar effect to using the footswitch to change from the rhythm to lead channel.

I would hear the lead channel for a split second and then, like RR wrote, it sounds like it just goes back to clean channel. Does this sound likely?

 

[RR]

Well, I think we, I and texmexboogie narrowed down its your channel switching mechanism whether its your footswitch or something interior.

I'm not familiar with newer MESA, but the older one (Mark I, II, III[?]) used an anlog relay.

Did you try a jumper wire (any wire) a connection between the tip and ring of your phone plug of your footswitch cable?

By the way, your footswitch cable is usually parallel cable like lamp cable or speaker cable. You don't need to use (coaxial type) guitar cable.

Seems like your Studio .22+ want to change to Lead Channel but fraction of second returns back to the clean channel.

 

[texmexboogie]

Well the only other simple remedy I can think of is tighten the nut on the chassis on the front ot the amp. A lot of things ground that way. If your not sure you are making a good ground get an old speaker or guitar cable and cut it. Then tie the to metal ends together and insert it in the footswith jack on the amp this should complete the ground. No dice, then it's internal with a bad relay, cold solder joint or failed power supple to the switch.

Be certain it is not a tube or ground problem before you get it serviced

 

[bamyasi]

hi,

I have just put in a tube and I can confirm is not a tube problem either.

I will take it to my local music shop, they say they have an amp technician there.

So I will tell them

1) the lead channel was fine and then there were volume drops, then the next time I turned it on it would not work

2) I have tried the amp with new working tubes and manually switching channels without the footswitch.

3) I tried cleaning out the effect sockets at the back of the amp.

Is there anything else I should tell them / ask them when I get there?

 

[RR]

Say to the technician that your footswitch might be faulty.

When you bring the Studio .22+ to technician, make sure he's present and test the amp first with another footswitch or grounding the tip to the sleeve before any repairs. Because it still might be a faulty footswitch.

I'm mentioning this because I hear horror stories where a guitarist brings his guitar amp in, and say it doesn't work but the technician isn't present, but later when the technician diagnose the guitar amp, its nothing more than a blown fuse but the guitarist has to pay an automatic bench fee something like half the technician's hourly fee even for the simpliest repairs.

Good luck.

 

[StephenF]

Sounds like it's a power supply problem for the switching circuit. I had similar problem on my .50 cal+. The power supply circuit to the LDR (electronic switchers that the foot switch controls) was bad. In my case, it switched....really...really slowly due to a cap being faulty and a resister burned slightly. (switching should be instantaneous, with only reverb delay being any remaining sound generated from previous switch position.)

Looking at the schematic, I would recommend for the tech you take it to, to check (what appear to be) R131 (1K-ohm, 2 watt) and C3 (470uf/16v) (2nd page of schematic, trace back from the footswitch jack to the supply line through D1, and check all resistors and caps). If this circuit is faulty, the switching could act all sorts of ways (not working at all, fade in/out, switch in and then fade out, etc).

Stephen

 

[bamyasi]

@StephenF

Thanks for the post, I am planning on taking it to a Mesa amp technician - he says he is just waiting for some information to come through on this particular model. I will definitely pass on the information in your post.

Like you said, the problem started with volume drops in the lead channel and now nothing, except what sounds like the reverb delay you mentioned.

thanks again

 

[MrMarkIII]

"I think you have an earlier Studio .22, no "+". Studio .22+ has three volumes."

Er, not quite. I believe you meant one "Volume" (Gain), a "Master", and a "Lead Master". Non-Plus models have no separate "Lead Master".
But yes, the Studio 22+ has three controls for gain and volume.