Krell primer?


I was hoping some folks could give me a primer on Krell amps. I’m in perpetual upgrade planning mode and have seen a number of Krell amps coming through A-Gon. I thought I’d ask for opinions. It seems that the FPB and KSA lines, which I gather are at least ten years old, are relatively reasonable in price and seem well respected. Can anyone comment on their sound? How much heat do they throw? Are there any ongoing maintenance issues with the older amps? I understand Krell still services their older gear, much the way McIntosh does.

Any comments would be useful. Thanks!
grimace
I have had the FPB-450mcx amps for 3 yrs now and love them. the heat will grow as the volume is increased. One of the amps needed to be returned for repairs because it would over heat and shut down on it's own. It works perfect now.
I have a pair of KMA 400,s contacted Krell service. they quoted $1000 U.S for service.My problem is I,m in Australia and the freight scares me. Does anyone know of a trustworthy Australian tech that does old Krells up.
I own a Fpb600 that has served me very well, not a single problem for almost ten years. Before that I had KAV series amps, but they were nowhere near the 600. Subjectively I even wonder if it sounds better over time (but this may be due to various accumulated tweaks). I especially like the layered deep soundscape with several things going on at the same time. A separate mains line is very much worth it. Also, the Aesthetix Io with volume, direct (balanced) to the Krell, is a great match, much better than with the KAV preamp I had.
I use the following Krell amps with great success: 2 pair of KSA 250 & 1 pair of MDA 300s. They sound great with Signal Cable Silver Resolutions interconnects, Ultra Speaker cables & power cords. I like the KSA series better than the FPB series. I do like the EVO series. You can always count on the KSAs to bring you themusic. Now I'm using thr ARC REF 3 preamp, Legacy Helix speakers, and the PS Audio Perfect Wave DAC and transport along with the Power Plant Premeir. They do heat up the house a bit. Even if you have to rebuild the amps the KSAs are a great buy as you would have to spend lots of $$$$s to get better sound . As for the sound, very liquid, nuetral, and of course solid. I don"t think you"d regret the puchase.
Hello All. Is the KSA-250 fully balanced from input through output?

Many Thanks!