Hi guys, I just had a quick question about the current Mesa/Boogie Mark IVs... on the site, it says it's 85 watts, with something called "Simul-Class" power. Does this kinda mean... that it brings it down to a lower wattage? Or what...?

Also on the front it has a switch with two options "Full Power" and "Tweed Power". I have a feeling the two things I asked about are somehow connected.. but yeah, could someone explain what both of these mean?

Thanks in advance.
Simul Class is in the power section...it allows you to either run all 6L6s, or a pair of 6L6 and a pair of EL-34s at the same time. All for your personal taste.

As for power-scaling, I believe the IV goes down to as low at 15 watts...using different combinations of full power, tweed power, Class AB, and Class A, you have quite a few different power configurations.
Ah okay, so you kinda have the option between 6L6s and EL-34s? Cause it says it 4x6L6 on the site, but I remember hearing in an interview that Mark Morton had a 6L6/EL-34 "blend" in one of his Mark IVs.

And then yeah, whats up with the power switch? Cause on the front all I see is a Standby switch but I'm kinda used to having another switch right next to it. I have a feeling the explanation is something really obvious and I'm totally overlooking it but I'm just curious.
like Eric said, there are several power settings. You can run 4x6L6, or 2x6L6 + 2xEL34. In simulclass, all 4 tubes are active, in Class A, only the outer tubes are active. When you run it in Class A with 2 x EL34, it will run the EL34 in Class A. The Simulclass/Class A, Pentode/Triode, and Tweed/Full give you different power options.

Simulclass and Pentode = 85W
Simulclass and Triode = 70W
Class A and Pentode = 50W
Class A and Triode = 30W

The Tweed/Full switch is supposed to act like an internal variac, lowering voltage across the internal circuit. It's main intention was to try and simulate the "brown sound".

EDIT: and there are 2 switches on the front, the power and the standby are right next to eachother.
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Last edited by Erock503 at Nov 15, 2007,