Boogie IIc+ reissue, and "Simulclass" question?

[G._Hoffman]

Gibson just released this puff piece on the new IIC+, and on a larger level I suspect the tone of this is what got Randall Smith fired (or rather, he wanted it to go a different direction, or just not do it).
But the more relevant question - does the whole Simulclass thing make any sense?  Because the way they describe it (two tubes in class AB, and two in class A) sounds like marketing speak, and looking at the schematic I kinda get what they are doing, but does it really make much difference to what the OT is seeing? 

I found a cleaner version of the IIC+ schematic than is in Doug's library, HERE.
The heat sink still does nothing, as seen at 2:59.

[shooter]

just a quick look, says it'll break in a year, with regular use 


my impression from the schematic;
they're trying to get both even n odd harmonics into the "tone" at the PA stage, while giving you enough power to overcome the happy drummer.
the analog complexity of the front-end seems in odd's with 21st century "modeling amp" environment. (see 1st sentence)

[G._Hoffman]

just a quick look, says it'll break in a year, with regular use 


my impression from the schematic;
they're trying to get both even n odd harmonics into the "tone" at the PA stage, while giving you enough power to overcome the happy drummer.
the analog complexity of the front-end seems in odd's with 21st century "modeling amp" environment. (see 1st sentence)

it's a reissue of an amp from the early eighties, so no great surprise it isn't a modeling friendly amp.  it has been pretty widely speculated that Randall Smith was fired from Mesa-Boogie because he didn't want to do this kind of reissue, and the higher ups at Gibson didn't want anything else. 

And yeah, it looks like exactly the same horse shit PCB design Mesa has always done.  PCB's are not inherently bad - I'd argue that, well designed, they are a better way to build an amp - but Boogie has always made some very poor decisions on PCB layout. 

[shooter]

yep, that's why I gave up on the "modern" PCB Marshalls n some fenders, bad soldering, cheap boards n foil, etal.  having spent the last 24 years getting to see 21st kids, they're just the right market for crappy things sold dirt cheap 

[DummyLoad]

I have a MkIII Blue Stripe with the reverb option and no graphic EQ -- Sounds really good and is supposedly a MkIIC+ voiced brighter and the last version made before Mesa went with the SimulClass crap. The lead channel sounds a lot like the MkIIC+, but can be much brighter, the clean is decent, the MkIII added a Crunch channel, but IMO, it kinda sucks. If you can locate an original unmolested MkIII, pretty sure you won't be disappointed. MkIIC+ are, IMO, overvalued.


--Pete

[Merlin]

But the more relevant question - does the whole Simulclass thing make any sense?  Because the way they describe it (two tubes in class AB, and two in class A) sounds like marketing speak,

Take a look at the simulclass patent: https://patents.google.com/patent/US4593251A/en?oq=4%2c593%2c251
Basically each side of the push-pull circuit has a triode in parallel with a pentode, giving a combined result that is very similar to an ultra-linear output stage. OK there are more details in the patent, but that's the basic idea.
Does it make sense? For hi-fi you can make a claim about lower distortion and output impedance at low power where music is mostly played. For guitar, I don't really see what advantage it is supposed to have, or what problem it is supposed to 'solve'.  It's certainly an expensive way to reduce crossover distortion, if that is what was troubling Randall.

[glass54]

Pity Randall dedicated little time to proper PCBs and service manuals!! I suppose the time was dedicated to generating reams of hype in those glossy release booklets (real snakeoil type info).
For those of you who have had the pleasure ( ) of repairing Mesa B**gies, TOTAL KNIGHTMARE. 
Long Live Leo