How to tell if Mark III has Simulclass.

[dennq45]

I just picked up a 1986 purple stripe Mark III medium length head. How do you if the amp has simulclass?
The only thing on the back panel is a knob for presence. The front has a switch for full or half power. Was simulclass an option? It does have the export transformer though. Kinda cool. It also came with all three footswitches and original cover. I had a look inside and its never been touched. It also has reverb and a cooling fan and EQ.

I dont want to put in two 6L6's and two EL-34's and screw up an otherwise mint amp. Any help?

 

[edward]

I take it then there is no "SimulClass" sticker on the back and has 4 6L6s currently?

To be certain, you need to pull the chassis and look at the output transformer. It should be a 562-003 if it's a Simul amp. I think this still should apply to an export amp ...someone please correct me if I'm wrong.

Edward

 

[Russ]

I think that there is also usually a switch on the back labeled Simul.

 

[Octavarius]

I think that there is also usually a switch on the back labeled Simul.

I heard that sometimes there wasn't. :?

 

[Bullen]

Yeah, on the wide chassi heads (which you have) sometimes the Simul-Class/Class A switch was just labelled Full/half power. On the short heads and combos the switch was on the back and was labelled right.

I´ve heard that sometimes Mesa put a Simul-Class sticker on the OT if the amp had that feature.

Otherwise, just like edward said, check the OT number. It should have simul-class stamped on a plate on the side (at least mine has) and have the number edward wrote. If it has another number, then it´s probaly not a Simul-Class amp, but a 100/60w version.

The Mark III was available in Simul-Class (75w, except for the green stripe witch was rated at 85w), 100/60w and 60w options. Eq and reverb were also options.

I believe that only the PT should be different on a export version, the OT should be the same.

 

[racer*x*]

im pretty sure my mark 3 is a simulclass!

 

[powerlord]

Thats wierd,mesa told me that the full and half power switch on the front was just another version of simul class,hence it is a simul class.

 

[edward]

Thats wierd,mesa told me that the full and half power switch on the front was just another version of simul class,hence it is a simul class.

Yes, but only on the long heads. There were short-head and combo MKIIIs that were 60/100 watt amps in which you *must* use 4 6L6s, and the switch was on the front, IIRC. They prob just didn't fully understand or mis-heard the question.

 

[dennq45]

Thats wierd,mesa told me that the full and half power switch on the front was just another version of simul class,hence it is a simul class.

I'm not 100% sure on this one.

 

[powerlord]

I see,thats why he told me mine was simul class because it's a long head.I didn't know this.I do have the EL34,6L6 tubes.

 

[dennq45]

For the record the serial # is 17633

 

[Octavarius]

What does it say on the side of the chassis?

Fully loaded exports are DRGX, for instance. Or a 100/60 would be HRGX. Then the production week. (5, 6, etc.)

D = Simul-Class
H = 100/60 Watt
S = 60 Watt
R = Reverb
G = Graphic EQ
X = Export