Let me clarify the opinion expressed in my previous post:
We know that fused neutral is a problem. An amp that has a fused neutral needs to be fixed.
We have been told that Surdo's used amp, which had been modded in the aftermarket, came to him with a fused neutral problem. He did some research, calling Flannery (a recommended "Sunfire expert") and was told not to use the amp until he had the wiring fixed. He had a local tech fix the wiring problem and now the amp has a fused hot. It's all good.
Some people (not me) have made allegations that all of the Sunfires appear to be wired with a fused neutral. I have no first hand knowledge about this one way or the other. Were all of the Sunfires wired this way from the factory? I doubt it. The amp in Surdo's photo has a CE certification sticker affixed to it, and to the best of my recollection the Sunfire amps were UL listed. If the CE sticker is genuine, and if these amps were UL listed and CE certified, then they would not have been designed with a fused neutral. The fused neutral condition would have to be a modification that was made after the amp's design was certified. Surdo's amp has crossed international borders as a used product in the aftermarket, it has moved across countries that have different AC input wiring standards, and it looks like it's been modified. Surdo's amp is most likely to have been modified in the aftermarket after the amp had left the factory. Looking at his modified amp doesn't tell us anything certain about the AC wiring of all of the other Sunfire amps.
In my opinion: Bob Carver is a really smart guy, and I can imagine NO WAY that he would design an amp to have a fused neutral. Bob Carver would have designed the amp to have a fused hot. This makes me think that if there are Sunfire amps out there with a fused neutral, then these amps were probably modded after they left the factory.
But someone has commented that all Sunfires were wired this way from the factory. I'm not the one making that claim, and I don't believe it to be true. If someone has a 100% original Sunfire amp, and they insist that it has a fused neutral, and they insist that it came this way from the factory, then here are my thoughts:
In my opinion: Bob Carver is a really smart guy, and I can imagine NO WAY that he would design an amp to have a fused neutral. Bob Carver would have designed the amp to have a fused hot. This makes me think that if there are Sunfire amps out there with a fused neutral, then these amps were probably modded after they left the factory. In the unlikely event that they came out of the factory with a fused neutral, then it's possible that someone on the assembly line mis-wired the amp. If you insist that your Sunfire came that way from the factory, I think it's more likely that someone on the assembly line might have mis-wired the amp than that Bob Carver would have designed the amp with the intention that it would have a fused neutral. Bob Carver is a smart guy. He knows better.
Surdo's amp is listed as having CE certification. CE certification suggests that the amp would not have a fused neutral in the design. Surdo's amp is a used amp. It looks like it's been modified. We don't know who might have put the CE certification sticker on it, but if we assume that the CE sticker is valid, then a valid CE Certification sticker implies that Bob Carver's original design would not have had a fused neutral. If anyone in the chain of ownership of that amp had fraudulently attached a CE certification sticker on an amp that hadn't earned it, then the CE sticker doesn't really tell us anything useful, and all of our assumptions about the amp's wiring based upon CE the certification sticker have to be thrown out. Let me be clear on one point: I am not accusing Sunfire of attaching CE stickers to amps that didn't deserve them. I don't believe that to be the case.
In my opinion: I don't think that Sunfire would have made this kind of wiring mistake at the factory. But IF they did -- and that is a big IF, then the amps were mis-wired as a mistake, and someone on the assembly line screwed up. IF that happened then it would be a materials/workmanship problem and the factory would take care of it for you. Unfortunately the company is gone now so if you have that problem then you have to do the fix on your own.
I wouldn't waste Bob Carver's time on this. We already know the right answer to the question about what to do if the amp has a fused neutral -- just fix the AC power cord.
IMO it's also a waste of time to go digging into this, just to try to expose who is potentially responsible for a mistake that might have been made 20 years ago. Just do what Surdo did -- just fix your amp and enjoy the music.
Carver Preamps: C-1, C-2, BillD's JVD-modded C-4000, C-9
Carver Amplifiers: BillD's C-500, M-1.5t (4) PM-1.5 (4) M-500t (2)
Repair/Restoration/Upgrade expert for all of these components.