The number of caps used in the filter supply section can be quite decieving, Although the 800 ch. switching Marshalls were not what you were inquiring about, they are probably the best example to use here. There are three distinct variations and the number of filter caps are different for each one....
1. Early ones had 6 LCR caps...like Super Leads and most early MV JMP's
2. Next ones had 5 LCR caps
3. Later versions had only 3 LCR caps, but they "twice" the reserve power than any earlier one's....doesn't make sense does it?
The Marshalls that have the "4 pack" of filter caps next to the trannies are actually running them in series.....when this is done the capacitance rating is cut in half, while the voltage rating is doubled. When they are run in parallel the capacitance is summed, and the voltage rating remains the same.
So, Marshall Super Lead plate reserve supply is (50 + 50uf = 100uf/500v for one cap) two 100uf caps running in series = 50uf/1000v
The later 800's (including the single channel) plate reserve is simply one 100uf/500v which is twice as much capacitance.
The same setup is replicated after the choke....
Running in series allows the caps to work in a much lower voltage range as opposed to continously subjecting one cap to 486v, while it's max is only 500v! This contributes greatly to the lifespan of the cap, but at the cost of "reserve" or "on demand" current. Of course, both designs have proven themselves very reliable.
Having said all this, more "reserve" power doesn't actually equate to "better" and does have an impact on tone as the supply is "depleted" when cranked...this is more commonly referred to as "sag" (as GJ discovered...
) but it does increase the "ability" of an amp to be louder before breakup.....
Most current production amps fall into two categories:
Those designed to please the most people possible, at an affordable price (which usually does equate to less power) which lends itself to smaller trannies (as pointed out earlier) and quite a few other "compromises"...simple economics.
And those that are considered "boutique" and carry higher prices to reflect better quality......(my personal "dream amp" design would retail for over five figures, which would make it "commercially unviable"... which would explain why it's a "dream amp" and not currently on the market!)...
The trend towards less power adds to the "decline" of megawatt amps, but introduces the element of "reliability"....
Ex.- My personal Marshall is capable of delivering 186 watts!, since I honestly only use maybe 50 watts max at a gig, it would stand to reason the amp as a whole would be much more reliable than using a 18 watt amp pushing all 18 watts night after night!
Hope it helped......
Jeff Seal
