Most of us have been on HF for a long time so there is good reason for our attitude. To us you are just like all those noobs on HF which look at the price of a component and think that has any bearing on its performance. To quote Oscar Wilde, "A man who knows the price of everything and the value of nothing". A version of this should be the HF motto...
Yup, the universal unit is the 378X.
Fucked would be a good approximation. The PSU is a clusterfuck of underrated parts and highly questionable engineering/build quality which was a ticking time bomb.
He was trying to push some half baked ES-1 (aren't they all) earlier this month. Claiming that the normal input was a preout or some other such nonsense.
Here is the full glory of the SP umbilicals. At least there is some teflon insulation on these wires or probably tefzel. The amps are all wired with PVC...
One thing Al (and all of those that own SP amps) check the umbilical cables on the inside. I just did and one wire was loose with plenty of them dangerously close to shorting out. Ohh, and it's built VD style with a rubber hose and some loose wires inside. One of them didn't even have anything to secure the techflex...
To open them up you just screw the back part of the plug. You need a bit of force but once you are inside the black clamp can be opened up with some pliers and it just pops off the cable.
Ari is correct. Shame on me but I'm so used to connecting ECC83's up at 12.6v that I forgot about the CT's role...
As for using the 6SN7's instead of 6CG7, it should sound better due to the better voltage specs for some 6SN7's but you have to watch the filament current.
They have the same pinout, the 6CG7 and the ECC83, ECC99 etc. minus the heater CT.
I also had this saved, presumably from HF:
The full list might be in order:
The different tubes used is certainly a part in the amps downfall. With the Extreme for instance there were some rather power hungry tubes used which when coupled with the crap build quality led to damage. The heater supplies were undersized and so were the HV lines.
Most manufacturers build and design their units to fit with one certain tube. All the operational parameters match said tube and the filament supply works just for it. Now that doesn't mean you can't put in some other tube to try. There are many close relatives with different pin configurations or slightly more/less gain etc. which should work just fine. On top of that you have the same basic tube design but with a different heater voltage. The ES-1 for instance was designed around the ECC81 and the 6CG7, both of which are easy to substitute for.
Some of those cheap adapters are identical to the SP units. My ES-1 lacks the ECC-1 unit so I checked and a 6CG7-6SN7 adapter is the same thing.