Mark III Identification

[telecasterkid]

I have read through hundreds of posts and still have doubts as to what version of the Mark III that I own. Please forgive me because I know this topic has been discussed I am sure to great lengths. This is what I have and the info that I have found.

Mesa Boogie Mark III short chasis head
Looks very much like a green stripe on the upper left pn the back of the amp.
Has a letter "R" handwritten on the chasis below the green stripe.
5 band graphic eq.
presence and reverb controls on the back.
"Class A" and "Simulclass" toggle switch on back.
Underneath it says 5/94 with somebody's signature.
Serial Number 28XXX

I downloaded the manual and from what I have read in it as well as this forum I believe I have a 1994 Mark 3 Simulclass, that I believe I should be able to switch the two outer tubes to EL-34's. RIght now it has four 6L6's in it. That's the way I got it.

So my questions are.........

Am I on the right track?
Can I indeed switch the tubes?
What is the wattage difference between Class A and Simulclass? I have read everything from 15-25-60-85 watts.

Any help would be greatly appreciated. I was going to email Mesa but all I found was a phone number.

Thanks in advance,
Kev

 

[MrMarkIII]

If it's a Mk III green stripe it's 25w "Class A", and 85w Simulclass. Earlier versions are 15/75. Yep, you can swap EL-34s in the outer sockets (only). The "R" is a factory reverb fix. Welcome to the club!

I have read through hundreds of posts and still have doubts as to what version of the Mark III that I own. Please forgive me because I know this topic has been discussed I am sure to great lengths. This is what I have and the info that I have found.

Mesa Boogie Mark III short chasis head
Looks very much like a green stripe on the upper left pn the back of the amp.
Has a letter "R" handwritten on the chasis below the green stripe.
5 band graphic eq.
presence and reverb controls on the back.
"Class A" and "Simulclass" toggle switch on back.
Underneath it says 5/94 with somebody's signature.
Serial Number 28XXX

I downloaded the manual and from what I have read in it as well as this forum I believe I have a 1994 Mark 3 Simulclass, that I believe I should be able to switch the two outer tubes to EL-34's. RIght now it has four 6L6's in it. That's the way I got it.

So my questions are.........

Am I on the right track?
Can I indeed switch the tubes?
What is the wattage difference between Class A and Simulclass? I have read everything from 15-25-60-85 watts.

Any help would be greatly appreciated. I was going to email Mesa but all I found was a phone number.

Thanks in advance,
Kev

 

[telecasterkid]

Thanks for your help. I really appreciate it. I swapped out the outside pair of 6L6's with two SEC EL34's and there is definitely a difference when you switch from Class A to Simulclass. I actually like the subtleties I am hearing. It reminds me (sort of) of channel three on my RK head that I have setup for Vintage with 2 EL34's and 2 6L6's as a power tube choice. For me this is my first Mark series amp and I absolutely love it. Different tonally and sonically than the RKI but a good different.

This now makes me a 100% Mesa user.
Mark III
Road King I
Mesa V-twin Rack
Mesa V-Twin pedal.

And now for my next purchase on the wish list.....
Mark IV or Lone Star

Thanks again,
Kev

 

[telecasterkid]

Just an update. I called Mesa and got a message back from customer service saying the only sure fire method to determine if my amp is trully a Mark III simulclass is that I need to look on the transforner for the word simuclass stamped in it somewhere? I gave them the serial number and described all the switches and so on. Does this sound correct?
And if so, where on the transformer should it be? Any help would be greatly appreciated. Now I am concerned that I changed the outer pair of tubes to EL34's.
Kev

 

[MrMarkIII]

"Class A" and "Simulclass" toggle switch on back.

Dude, if you have this switch, it's a SimulClass.
You may have to remove the chassis to inspect the OT (Output Transformer).
Hint: It's not the one closest to the A/C cable.

Here's the manual:

http://www.mesaboogie.com/manuals/Mark%20III.pdf

 

[telecasterkid]

Thanks very much again for your assistance..I will re-read the manual. BTW It sounds absolutely awe-inspiring in Class A mode with the new EL34's. I haven't got to open her up and really take a test drive in Simulclass yet.

Kev