Big Krells Have Vanished From The Used Market

"Big watts are unreliable due to heat."

Disagree. If properly and conservatively designed, hot running (class A) amps are very reliable.

Case in point, my Threshold SA6e’s from the early 90s are still running strong with never a fault. At 25 years of use, I replaced the power supply caps and rectifiers (both easily available from Mouser/DigiKey) as preventative measures.  And still going strong.

Wow I'm very very sad i only have 350W channel oh well!!!

Wow!, Ridiculous!, I have a modified krell fpb 700cx,  never runs hot because you have to use a single pole 30 amp breaker!, anyone who has a big krell that runs hot does not know what there doing!, as far as class d amp's,  listened to many,  still do not own one,  and yes, I'm holding on to mine for sound reasons,  my unit sounds a lot better than the stock 700cx 😉

They are few and far between.  I purchased a pair of fpb-750mcx blocks thru Audiogon a year ago (there were 2 sets available at that time - both in Canada) to replace a KSA-300S that wasn't up to the task of being able to properly jam the bass panels on my bi-amped Apogee Divas.  Each Krell has a dedicated 30amp wire; as do each of my Audio Research 610T's (upgraded to run KT120s), which run the highs and mids.  Many probably scratch their noggins over having this much power on hand, but I suspect those folks haven't heard the magic of Divas when properly powered.  My KSA-300S ran really hot and would actually throw its breaker...not surprising for what I was asking it to do.  The 750s do NOT run super hot like that at all, but they are warm.  Of course the tubes on the AR's are giving off considerable heat anyway. Luckily I have a separate Hvac system for my listening room, so it's not an issue for me.  Zero complaints about the big Krells.

Guys, there will never be a better amp made, pound for pound, than the FPBcx series - 300, 400, and 600 WPC. There ARE some that occasionally hit the used market, though agreed considerably less often than even 3-5 years back. I nearly pulled the trigger on a 400cx within the past 6 months and chickened out - ONLY because of the "risk factor" of dealing with costly repairs that I presume WILL eventually be needed. I've been very lucky, knock wood, as a proud owner of a 300 FPB cx since 2001, and couldn't be happier. 

Anyway, I also noticed a 600 FPBcx on the market within the last 6 years. Several in Europe as well but not practical. I love my Krell, and while I've considered jumping into some new power amp, I've decided it's just not sensible to move from known greatness to "who knows?"  I'm holding onto it until it needs service. If and when that day comes I'll move to something else.