I scored a couple of the SX-500 monoblocks and am enjoying shaking them out.
My setup is Jolida JD-100 > AR LS-3 > SX-500's. Mainly for 2-channel.
The SX-500's are clean and quiet, flat response not weighted high or low. Bass is t-i-g-h-t! My previous amp was sloppy and the Wyred amp is
fast down low.
I was a bit disappointed in the amount of the low end and a seemingly strident high end but I have just started tube rolling and my conclusion is that these amps will give exactly what they get. It is not a forgiving amp but as far as I'm concerend, that is a good thing; tweak the front end. I swapped out the very detailed Electroharmonix tubes from the Jolida and dropped in some new-issue Mullards. The low end is now prodigious and the highs rolled off via the tubes. I don't think this is the final tube for me, though. I've ordered some Tungsram, as people rave about them in the Jolida. Like all, I am looking for the holy grail - detail, good low end, mids, and extended-but-smooth highs. I feel the amp is going to precisely communicate any upstream changes.
The input buffer is a nice feature. I just turned it on and the highs seem to have a little more presence, so that is good with the current tubes.
The monoblocks have a 4" blue horizontal power light that looks kinda cool, not too bright. Nice in the dark.

Amps are solid.
EJ has answered all my questions. I think Wyred offers a good number of options, including mod packages should you want to go for the full monty. I might trade up to some SX-1000's because, as we all know, too much is never enough.
