Old Krell vs new Krell amps...

Early Krell balanced amps used a pair of RCAs for the balanced inputs thus the XLR input change I suppose. The KRS amps are impressive but do use a lot of power and will probably require some service in the near future. Also, they are very heavy and shipping will be expensive when service is needed.

This is an old thread but I'd like to add a few comments here. ONE, the quality of the Krell amps sound is very VERY dependent on the supply power, 220 Volts and lots of it is ideal. The amps, any Krells, can sound flat, restricted and edgy on weak power. You have not heard how sweet they can be until you have heard on a good power supply. SECOND, I do not consider any of these unreliable, these are extreme performance amps that use a ton of power and create an enormous amount of heat, they are supposed to be serviced every 10 years! Look, Ferrari engines never last very long, they rev much higher and work much harder than a Honda civic so yes they do wear accordingly. Want low maintenance get a Adcom amp, and why are tube guys even discussing reliability?

I have heard Krell amps sound poor many times usually from poor installation or system matching. My 2250 will sound more dynamic than my FPB750MCX amps on a weak 15 amp 117 volt line; on a 220V 40 amp line the FPB Rocks! I also have a 100 amp isolation transformer with individual windings feeding the amps, they don't sound flat.

I think to properly compare the amps they must be under proper conditions and within the nominal service expectancy. If you compare a new EVO amp to a 15yo KSA 250 on a 110V 15 amp circuit of course the KSA will be at a huge disadvantage.

I have had the KAS's since they were released. They have been magnificent performers and only a month ago did one of the mono amps go up in smoke. Thus ~20years of conitnuous enjoyment. The amp is at the factory now for repair. I sent the other back about 2 years ago for repair. Otherwise they have been extrememly reliable for such high perfomance.

Fjmcsu, just wondering what speakers you drive with your KAS.
I am considering buying a pair of them and would need some guidance:
They are meant to be really good at driving very low efficiency and/or very low impedance speakers.
At the same time, many people consider the KAS to be fundamentally more musical than many other (and more recent) Krell designs.
The question is whether it's worth going for KAS if you don't have such load issues. I have a pair of JM Lab Utopias. They are not as hard to drive as the famous Apogee speakers (which made the KAS very famous as they were hard to drive with anything else), and they have decent sensitivity. They just need top quality amplification because they are very transparent, to be thightly controlled and some current.
The KAS will most likely drive them across the first 2-3 steps of the 5 stage bias system (ie I will never need more than 125W I think, most of the time even below 50W (Level 2).
Does it make sense to go for the KAS with a pure musicality objective in mind if you don't need all that power?
Moreover, does the KAS perform as well at low power than at higher power? You could argue that on the first couple of bias levels it is so cold that you'd wonder if the various components operate at their nominal temperature...
I currently have a KSA-150 (for ages). It has way enough power for my system and it took me a looong time to consider switching. Do you think I am going to experience a significant sonic improvement by switching to KAS?

Thanks,

I own 2 of the Kas-2 (purchased used 5 years ago). One of them went up in smoke, and I am reluctant to send them back to Krell. They told me (judging from the picture: top of circuit board burned badly), they do not have the replacement circuit board anymore, they can't fix it. I live in California, shipping would be very costly. Now that I hear about yours going up in smoke, I am scared to spend money on them. I love the sound, but Krell is not accommodating me at the least. Can you give me an idea? Attila