c+ modded mark IIs

[Meson Boogie]

I've read here that modded mark IIs should essentially be identical to an original IIc+ (aside from the debatable difference in feel - psychosomatic?). Anyway, does this include the extra pull tone control found on the c+? Also, how do the power amp stages compare in terms of circuitry? Apologies if this has been asked already, I did a search but couldn't find any referance to this.

Thanks for any interest and answers.

 

[Boogiebabies]

Any IIA's or IIB's would have had full circuit board swaps and faceplates.
The IIC had six pull functions anyway and there were two ways to upgrade them. Early IIC's had and RP10A preamp circuit board which could be modified to a + because it had five LDR's. Later IIC's had the RP11A or SP11A circuit boards which were designed for the IIC and basically requires moving some components around. The RP11A and SP11A were later used in the C+ production. Now, getting dozens of different brands of components, three different power transformers and two power amp options to sound the same is not likely. Throw in 30-40 volts difference in plate voltages, different dropper resistors and preamp voltages can equate to differences in tone from what could be considered the same amplifier series. After you have owned a few you may not consider opinions to be mental in origin.

 

[Meson Boogie]

Thanks for the details. Pardon my ignorance, but does this mean that the c+'s used the same two power amp circuits as other mark IIs? I'm guessing the mark III power section was different given how I've read the blue stripe version had the power section changed to make it more plus-y.
Basically I'd like to know if getting a mark IIa or b will give me equivalent (roughly, given different transformers) to a c+ power section.

 

[Boogiebabies]

The 60 and 60/100 are nearly identical in the A and B with different presence circuits. The 60 & 60/100 C has the same power amp specs as well, but again with a different presence circuit. The Simul-Class is close on the B and C, but you also have to deal with the 100 power transformer putting out 460V opposed to the 105 at 490V. If you look at the transition from the C to C+ you will see the extra 30 or so volts equates to more volume, headroom and a less power amp sag. Not to mention that it almost always runs cool and is a rarely stressed huge chunk of iron. Now, take this as you may, but I will refer to the 105 as a bottomless pit of power and clean drive. When the MK III came out Mesa switched to what they would probably determine as as a more efficient power transformer.
It too put out 480-490V or so, but I don't think it reacts as fast to supply the power amp with power under load. We can speculate as much as we want, but the MK III basically boils down to a IIC+ circuit on a single board with a point to point wired power amp. The components were all basically the same as the C+ so pretty much everything was there, so why were there so many changes to the power amp and why were subtle changes needed to the preamp. To me, it all come back to the power transformer and how it reacted. With each stripe is an attempt to hone in on it predecessor, who's PT was twice it's size and bottomless. Needless to say, the MK III stripes offer players a slightly different flavor to play. It's in no way a mistake, but an evolution. They are unique in thier own right and a joy to own.