A couple of years ago I upgraded from a S/300 series II to a S/350e. The S/350e idles hotter than the S/300. The reson: the e series amps operate at a higher bias than their previous interations in the S series. Here's a tidbit from the e line manual: "The tracking accuracy of the optical bias circuit has allowed the biasing of Threshold S/model amplifiers to such levels that are now designated class A/AB in operation. This means they will function as pure class A amplifiers until about 20% of their instantaneous power rating into 8 ohms, and operate as class AB beyond that point. At idle they generate as much energy as their class A counterparts, but they operate at higher voltages so as to deliver higher wattage to the loudspeaker." For what it's worth my Threshold is a keeper and is not for sale. The list price of the S/550e was $6300. If you can get a mint S/550e for $2100 or less that would be a good deal.
Any help on Threshold s550e amp?
I have a chance to buy mint Threshold s550e amp by Nelson Pass - asking price about $2500. What is comparable in new amps and what are the opinions re the Threshold s550e. Any help would be appreciated - am currently running Thresholds300 into B&W 801 series two, Threshold Fet10 control amp and phono amp. Thanks.