Since the first gain stage is in the shell, if I use my RM4 which has a Fender gain stage I'll have to install a bias switch so the Marshall type modules sound good.
A less invasive method would be to change the cathode resistor and bypass cap to the marshall values in the shell, then compensate at the module (the fendery ones) for any loss of bottom end.
For the Randall modules that means increasing the size of the input cap (C1 or C3 depending on the module) or using the tight/bass switches on the dual channel modules.
This way you can always revert back to stock if you want to.
Also you set the bias on the module with the Synergy stuff, so it's all down to preference. You might like the Marshall modules with the stock fender values.
I don't know if I'll be able to midi switch between each channel in a Synergy module.
The midi switching works as normal but you only get the blue channel of the module. If you want to access both channels with the RM4, you will have to buy and install the dual channel mod.
The Synergy modules come with a channel select switch for use with the older single channel hardware(Randall), so you can pick between red or blue. However this isn't on all modules. My BE doesn't have the channel switch. I don't know if it's by design or if they were only added to the later revisions.
I don't know if the modules are voiced for the Synergy power stages, or whether my RM4 will sound good. Seems like Synergy didn't go as far as they could have with the power amp which only takes 6L6s. Don't fancy Marshall sounds with anything other than EL34s.
My BE sounds fine with the EL34L's in my amp. I can only speculate about the voicing. I don't think the power valve type comes into the equation much. They switched to 6L6s at the last minute for the heads, saying that it was for better tube reliability. There are plenty of Marshalls that use KT88s or 6550s too, so again, i wouldn't worry about this IMO.
Tough choice between the Plexi, Metroplex and JCM800. Plexi sounds very authentic but I like the slight extra gain in the Metroplex. Tough choice between the Bman and TDeluxe, but think I'll go for the latter. Everyone raves about the SLO. Have room for one more. Impossible to try them out in NZ.
Tough choice indeed! If it means anything, the Metroplex seems to be the most resold out of the lot (together with the HBE). I think the Dirty Shirley would cover all three of those but the Friedman voicing is slightly different. Even the BE might. I don't have anything Plexi like to compare it to.
The Bman blue channel is the cleanest out of those two modules if that's important for you.
I wonder if the curved sides of the preamps will look shit in the straight sided cavities on the RM4. Rather have two Synergy preamps but not sure I can justify it.
The curves look fine. They don't go past back the screws so it you cant see into the cavity, still plenty of overlap.
I'd much rather have one RM4/M4 than two SYN2s. There's no way to justify the cost difference IMO (in NZ), even with the extra in/outs of the SYN2.
If anyone wants to sell their RM4/M4 in aide of acquiring a SYN2, i will happily take it off your hands.