Vintage Krell

Spinaker you made the right choice. You get a lot more money for them before they blow then after. Every last one will blow it's output stage eventually just light an incandescent light bulb. But, they were a great performing amp. They certainly opened my eyes (ears) as to what was possible with ESLs. I discovered that ESLs had no problem going real loud and being real dynamic with the right amp. 

Yeah you’re probably right, they worked great in the 18 months or so I had them though. With a pending marriage and house costs, it was just getting too costly to keep chasing the high end. From the pictures I’ve seen of the insides over the years, they look surprising basic and possibly easy to repair compared to modern complicated units stuffed with surface mount devices. Are/were critical parts hard to source...Krell only? At the prices they go for now, I still find them tempting!

I have some Vintage Krells (3). 2 of them have been recapped and serviced (KSA-200s - KST-100) I also have a KSA-250 that I have not yet gotten recapped but was checked for running operation when I bought it at a service center. These amps are the best for me with my Martin Logan ESLs and Montis. My take is that the Class A and power reserves, output transistors from them just is superior to other amps I’ve tried.

Currently I’m in love with my KSA-200s in my system. I have to say that the bias technology in the KSA-200s runs very cool, at full power or idling. I can say that the KSA-200s is one of the best out there, and the KSA-300s is even better if you have the speakers than can handle the extra power. I may some day get one of the KSA-300s for my collection. The KST-100 and the KSA-250 are the generation before the adjustable bias on the KSA-200s. They run very hot, and can heat up a room without AC. Oh, the sound though. I bought a recapped Mark Levinson No.331 and sold it and got another Krell. Mark didn’t really gel with the Martin Logans. Shame. It was the most beautiful amp I had ever seen. KSA-200s is supposed to be the most musical of all the Vintage Krells (KSA-300s too).

KSA50, KSA100 and KMA100 monoblocks there were ones with internal chimney heatsinks that were fan forced and had proper amount of Class-A on them into 8ohms, KSA50 had 50w the KSA, and KMA had 100w

The other later ones with external heatsinks were just high bias Class-A/B 10-20 or so watts. Then there were the Plateau (sliding) biased ones, that never sounded that go to me.

I dare say these rare monoblock ones had some decent amount Class-A bias on them.
https://www.stereo.net.au/forums/uploads/monthly_2018_06/Krell1.jpg.08d9bad55214fd21499f9f4bea6e2313...

Cheers George

The KMA 100s ran class A up to the rated power. The amp always seemed a lot more powerful than 100 ways. They never ran out of steam. Getting to 100 dB on full range ESLs, no sub was easy. I suspect they kept going in AB mode. The power supply was huge.