I'm guessing that the at least MANY of the OPT's were toasted because of having things not set up quite right in the output stage and then running it full out; Imbalaced push/pull setups with tubes gone or arcing out with overrated or foil fuses, bias currents all out of whack, plate resistors smoked, accidentally uplugging the speaker cable from the extractor for a second with the thing in mid blaze - All the things you can get away with a lot of the time under normal circumstances which'll otherwise take things out in a big way, and often nearly instantaneously when the amp is under full load... I don't know.
Though it would seem that the gauge of copper used in the OPT windings of a well designed amp would be far too heavy to instantaneously open or fuse, but all it takes is an extreme surge blasting it by something like the momentary shorting or removal of the load on the secondary side when the amp is working at full capacity for that extreme momentary current surge to zap a burnhole right through the weakest point of the insulating laquer coating on the windings, and it's done. It'll always arc across the residual carbon anytime the current flowing through that transformer even gets to a moderate level.
In very much the same fashion that once a phenolic or bakelite output tube socket has played host to a resident tube arcing from pin to pin; even after a thorough cleaning, and re-tubing, trace amounts of carbon are left behind embedded in the material, nearly ensuring that currents will again follow that same carbon path, arcing all over again and destroying a perfectly good tube and possibly more. That's why God gave us ceramic tube sockets.
Though I was meticulous about always making sure that little 50 watter was perfectly set up at all times, and that rig was played with the 50 watter on about "8" day and night for years, I never once had any problems. Not or so much as even an output tube failure or worse yet "catastropically" arcing from pin to pin, much less an output transformer.
That role was exclusively delegated to the fatassed Marshall Majors that had over 700VDC on their plates. Since that was too much for modern 6550's to routinely handle, even with a proper re-bias to accomodate 6550's, and KT-88's were next to impossible to find, much less in matched quads, the ones that I could scrounge up that WERE employed were embarrassingly old and of unknown history.
Banging around in the backs of U-Haul's across the country and routinely being brought in from sub-zero ambient temps only to be fired up to full red-hot internal operating temperatures didn't fare well from any kind of perspective of enhanced longevity, either.
When one of those old KT-88's would fail, it was usually a fairly major chain destruction type of event, due to the extreme voltages and currents living in and around all aspects of those archaic output stage designs which were set up around the idea of milking over 200 watts from a single quad of tubes.
Ok sorry, I'm way rambling. Back to the point...
As far as I am aware the Alan Holdsworth Juice extractor featuring Hush IIC and 3 band fully parametric filter stage was the only model produced.
Have no explanation for how it could have sounded awful in application except in the cases of the fairly obvious, such as coupling it to the output of an amp whose output capabilities were way in excess of the 100 watt rating which wouldn't be all that uncommon as even a healthy 50 watter can frequently hit sustained peaks of a true 80 to 100 watts regularly.
Though I've never tried it, I would be a little skeptical of opening up a healthy 100 watter into one for any extended period of time for fear of smoking the extractor's 100 watt rated load section from heat and or current excesses. And once that's smoked, there goes the next weakest link in the amp...
I suppose another awful sounding scenario might be pushing a hybrid or solid state output into it in order to achieve output saturation, which in most designs would only yield highly unmusical nasty square wave garbage.
Or I might have just coincidentally struck on one of those freak magical combinations that normally didn't happen...
That sounds like an appropriate cue for me to shut it. Besides, I think this thing is about to run out of ink...