Oh, the output transformers are the most magical part of the amp! According to Bob, their bandwidth is "so good it was difficult to believe".
In his auction description he mentions that his heroes are Albert Einstein, Mahatma Gandhi and Stu Hegeman. And, after much investigation, he concludes that one of them designed those transformers and, perhaps the whole amp.
Carver describes how he spent hours studying schematics and talking to people at Packard Bell. They had no info on the amp but they gave him the name of a guy who, when he was young, once worked there briefly as an apprentice. The guy told Bob that he vaguely remembered some old guy who was supposedly an outside consultant of some kind who designed amplifiers. This old guy would visit the factory on occasion. That was all he remembered. Bob asked him if he had ever heard of Citation amps. The former apprentice said the name sounded familiar, but that was all.
Carver then states, "That was enough for me! Taking all the evidence together, I am now virtually certain this output transformer, if not the whole amplifier, WAS designed by Stu."
I bet the kid had heard about the Theory of Relativity too so I think it's just as likely that it was Albert who designed them. I'm ruling Gandhi out, though.
He included answers to some questions about the OTs in the auction. Again, click to enlarge.
View attachment 1267360
If anyone has the ability to measure them I'd be really interested in seeing if their results are similar to his and, especially, how they compare to transformers used in similar console amps. It's hard to believe that there could be that much difference in their construction or performance compared to other similar transformers.
The Sams lists a Packard-Bell part number and an equivalent replacement made by Ram. Since I doubt P-B made their own transformers, I speculate that Ram was the OEM. A quick search indicates that there is a Ram Transformer Co. located in New Rochelle, N.Y. but that they were founded in 1995. Perhaps they are a re-organized version of an older company??
The Sams lists the Primary as being 5.5k CT and the Secondary as 3-4 ohms. Carver states that "the ohm rating on this amp ranges anywhere between 4 to 16 ohms" - so as not to discourage potential buyers, I'm sure. He does not specify the load that was used to take measurements but using 8 or 16 ohm speakers would affect the amp's performance, I assume. Perhaps someone with more technical knowledge could comment.
Carver is clearly a marketing genius. Take a fairly typical console amp, replace a few parts leaving most of the original ones in place, do an "exotic mod" that might cost a dollar or two, spray a couple coats of bright red paint on it and sell it for $1075.00! That shouldn't surprise us at all considering that it was designed by Stu Hegeman and the few parts that were replaced were actually soldered into place by the famous Bob Carver himself.
Never mind that the mod might not actually do much of anything unless you turn the amp up all the way. You DO listen to your amps with them turned up all the way don't you? No? Me neither. I'd be interested in seeing if there is any measurable difference at, say 3/4 power, which is still probably higher than most people typically use.
OK, he does say he made a few other changes, although some of them are difficult to confirm in the pic, which I'll post again for easier reference:
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"I increased the open loop gain". Is that the gray cathode bypass cap he apparently added to the 12AX7s on pin 8?
"I changed the feedback". Hard to tell.
"I have regulated the screen voltage". I see absolutely no evidence of that. There is a (1000pf) ceramic cap between the plate (pin 7) and the screen (pin 9) of the 6BQ5s, exactly as shown on the Sams schematic. Nothing more that I can see.
"Beyond that I've given it every de-lux circuit feature known to Man, Woman, or Minor Wizard."
Perhaps some of the Minor Wizards in residence here will weigh in on this. I have not ascended to that status yet and I doubt I ever will.