Threshold S/500 Power Amp or ???

Is there anyone still using this power amp now? What versiona and what are your thoughts regarding the S/500 driving Magnapans or Eminent Tech 8 speakers? I ask because I do love the sound or my S/300 especially where depth, width and height is concerned. It also does a wonderful job of playing jazz and vocal music. Int particular choral music sound devine from this amp.

If you are still or have used the Threshold S/500 to drive planar speakers chime in please. You have the experience I am looking for. My dear friend introduced me to the use of the S/300 and Classe DR-5 and I am having a great time listening ot this combination play music. The Threshold sound has captured my imagination. My Classe pre amp and Threshold power amp work very well together. However, I agree with my friend that a tube pre amp might serve me better as I look to upgrade my sound and I will continue to buy used equipment to save money.

By the way, my listening room will be 15 feet wide by 22 feet long with a 9 foot ceiling. The room is in the basement of the house with concrete floors. Finally, I don't want to have to change 8 or 10 KT88's or 6550's so I will stick with a solid state power amp and prefer the Thresholds because of their great "tube like" sound. At least that's what I hear with the S/300 and would think the S/500 would not be any different. Your opinions please.

Music Man Bob
I was using the S500II to drive a pair of Infinity RSIIB's for about 2yrs.It's the non-optical bias amp and is still all original.I enjoyed it alot,deep strong bass,midrange quite smooth,and extended topend.I'm using it now to run the bottomend in a bi-amp setup with a Mac 275v on top.The S500's soundstage was more forward and with alittle more edge than the Mac.I've also read that having the amp refurbished by a fellow named John Soderberg(Vintage Amp)would make a overall sonic improvement..I feel the emits,emins sound better with the tubes than the Threshold. but if I didn't I wouldn't have been looking to use a different ss amp.
I use a pair of Threshold S500 II's to drive my Infinity RS9 Kappa's. These amps have been refurbed with the main power caps replaced, bias adjusted and various other updates.
I cannot imagine any amp better controlling the bottom end of these speakers. The K9's have an impedance dip at 30Hz to around 1 ohm and these amps have no issue with it just providing overwhelming power to the speakers.
At the other end of the spectrum these amps have remarkable fine detail and definition with pinpoint sonic placement and correct spectral expectation.
I would concur with your thoughts that the 500 will sound like a 300 as I have both. I also have an SA2 and a 400a as well as a Cas1. They all drive infinity speakers with tough impedance loads although not quite as severe as the K9's. Just great amps!
Hello To You,

I was under the impression that the S/300 and S/500 were not good at acting as mono amps. I have an S/300 presently. I had intended to get another one and run both as mono amps. Are the S/500 so much more different than the S/300?

Besides more power, the S/500 will stay in a higher biased state longer than the S/300. So even at moderate levels the S/500 might sound more suave. BTW, the series II and the e series have their benefits over the original S series.
I recently "upgraded" to an s/500II from an Adcom 555 to run my Apogee Duetta Sigs. A spectacular improvement: enormously more detail and precision, especially in mid- highs. Bigger stage, more "air," and greater dynamics. The bass control, however, is perhaps the most startling improvement - it's so much tighter and seems to go deeper now. I had been happy with the old set-up for almost 20 years. Now I have the bug again, am questioning everything I have. I had fogotten how much fun this experimentation in the quest for "perfection" can be. Just bought a DAX-1 and plan to bi-amp (with a smaller Threshold s/series for the mid-high ribbon.)
I run the original S/500 (along with Threshold FET-10/HL and PC preamps) with Magnepan 1.6QRs. It's a great amplifier - good enough for me to give up the tube quest (for now). I'm to the point with this current system where upgrade-itis has been greatly reduced.

Can you tell me more about your experience with the Magnepans and the threshold combination?

What is the difference between the S/500 optical bias and the S/500 Series II?  Did the Series II omit the optical bias?  I've also noticed a few with balanced inputs??
Optical bias followed the Series II. Balanced inputs were introduced with the e series.
Many of the Series II units were upgraded to optical bias, and some  units  were upgraded to quasi e series with balanced inputs, though unlike the true e series with their dual trannies, they were balanced inputs only and not true balanced.
I believe the input borads had to be changed when upgrading an optical bias unit to quasi "e" series.  Any sonic improvement when upgrading the optical bias to "e"?

The e series were a tad more powerful, more vivid, less relaxed.