It is rewarding after all these years to see an objective measurement of this amp. I bought one new in 1997 and used it in a number of configurations over the years. It finally gave up the ghost a couple of years ago and is confirmed as unrepairable by my local trusted tech and by Bill Flannery, the last standing dedicated tech for Sunfire products.
I was always attracted to the physical appearance of the amp. I expect the golden lit Joule meter was more Bob's obsession with tubes than a desire to provide any useful instrumentation. Look at the vacuum tube preamp from Sunfire, he uses mirrors to make the internal tube compliment look like it goes on for infinity.
I never had any issues with inrush current making my lights dim or the transformer groan. I did have a ground hum that I could never quell. The only solution was progressively less sensitive speakers. When I got to my 83db ET LFT8's it was as close to dead silent as it was going to get. Most of its service life was in 2ch, generally in a bi-amp for 4 of its channels, occasionally running the 5th for a passive sub. That is where it was when it finally died, but in HT running the front L+R and an SVS CS20 sub.
The "current" source taps were always a gimmick and again, some sort of sublimation of Bob's hot sweaty vacuum tube dreams. I used them on and off but always went back to the "voltage" source taps. Despite what some subjective reviewers have said about these amps (the original 300wpc stereo version and all of its descendants) I never found the sound objectionable under any conditions. I am gratified to know that despite the distortion figures these beasts did deliver the rated power.
As I look at the cold, dead hulk, sitting in my office, still unable to toss it in the e-waste pile at the county transfer station, I remain convinced that while it was not a bad purchase, had I bought a B&K ST-140 at that same time it would still be running. Oh well.
