Krell KSA 50 vs. todays ss amps?

I have never heard a KSA50 but they get great press. Has anyone who has heard one compared it to say the Halcro( which also seems to get great press) or to any of todays ss amps, like Edge or Mark L etc.
Some reading and a picture:


A well designed amp is a well designed amp - regardless of
its age.

Amplifier technology is pretty mature - that is it isn't
like computer CPU technology where every year the processors
get better because Intel can put more, smaller, hence faster
transistors on a chip.

Amplifiers don't bump up into that limit. So just because an
amp is "new" - doesn't mean it's better.

Dr. Gregory Greenman
Not sure if you're talking about the original KSA50 (and 50Mk II, which I owned for a while) or the 50S, which Dave sent the links about. I must say the old KSA 50 was a very nice amp, quite sweet sounding for a solid state design, with far more power, bass control and clarity than any solid state amp I was hearing at the time. If I still owned it today I might recognize that today's designs, at the top end, might have better quality parts available to them now (higher speed diodes, maybe some better power supply regulation, etc.) that might make them objectively better, but I'd probably still be happy with the sound of the Krell. Going purely from my memory, I don't think it has the refinement of the best solid state designs available today, but it is a well-engineered design that has a lot of strong points. John Atkinson a few years back did a comparison of a Krell KSA 50 Mk II (he always seemed to like that amp) against a new Krell design, likely one of the FPB series, in Stereophile; his comments at the time were interesting, and did not find the KSA hopelessly outdated, if I recall correctly. Worth tracking down, if you can find it.
Perhaps, the sweetest sounding amplifier in Krell line up at that time along with the KSA 80. To be candid here, I haven't listened to any of their current series of amplifiers although at that particular time, the more powerful krells couldn't match the musical integrity, nuance and articulation of their lower powered siblings. That said: I would still choose the little 25 watt/ch class-A Bedini over the baby Krell for exactly same reason.
Dave, thanks for the links, but that's a 50S and NOT the amp I was referring to. The little KSA50 is an older model, but is supposed to be one of the best amps ever made.
I still am wandering how it compares to the amps I mentioned above... anyone?
I used to own a KSA50. It was NOT "all that", as my daughters like to say. Shrill on the high end, etched, but ballsy bass for something of it's power rating. When I bought it used(~1992) everybody else was drooling over the KSA250, and to a lesser degree the KSA150. Years later, I still recall many Krell nuts searching for & bidding up prices of 4-5 yr old KSA250's to almost the level of their brand new, newer models, FPBxxx. Rumor had it that many were being purchased by Japanese Krell fans, who were willing to spend crazy sums at the time. If you get a chance to hear a KSA250 or KSA150, I'd check it out in lieu of the 50. The KSA80 was a comparable model, I belive, but with slightly more power. Cheers,
I traded in my KSA 50 for an 80; the 80 indeed did have more power, was more refined (once it warmed up) though not quite as sweet in the highs, had better bass quality and control, and generally was a better amp. Big problem with the KSA 50 was that it used a cooling fan, which could eventually wear out, vs. the 80's massive heat sinks. Both of these amps could heat a good sized room, as they ran in Class A all the time. Neither of these amps can give you the midrange of a great tube amp, but both of them excel at delivering power into demanding loads, which is what their design goal at the time was (no coincidence that Krell was often demoing with Apogee speakers).
Over a 15 year stretch I have owned 2 KSA-50MKii's. This amp and it's 100 watt Mono version KMA-100mkii put Krell on the map and in the homes of reviewers. These amps set the bar back in the late 80's and early 90's. The follow on series took the cooling fan out and placed the output transistors on the convection fins. The KSA-80B, KSA-200B, KMA-160B, were some of the finest amps that Krell made. These units were raved about by reviewers. After that Krell was on a mission to take the labor costs out of the production of it's amps. This made good business sence for Krell, but after the 250, the lush trademark sound was removed, along with the cost of manufacture. The S series was not reviewed well at all. Within months of the introduction there were a few units for sale each month in the back of Sterophile (well before the A-gon days). That series of product cost Krell, as reviewers were then clamoring over the new Levinson 331-333 amps.

I have compaired the KSA-200b and the KMA-160b to the new 250MCX and I prefer the sweetness of the older amps. You dont see too many of the older units moving here on a-gon, So I can not be alone on my assessment.

The fan units always get knocked becuase people contend that they wear out. In the 8 years that I had owned fan units, I never had a problem with a fan. I would annually, carefully remove the cover and blow out any dust. These were not cheap fans that Dan choose to use, and they do not wear out like a $5 bearing-less motor. Krell still has replacement fans if you do have a problem. Bottom line is that I would not shy away from this technology at all, and for the price it is a bargin.
I think that the older Krells like the KSA50 are better sounding then the newest Krells being manufactured now. The older Krell has a very sweet sound with lots of presence and midrange warmth. It delivers the musical goodies. In comparison, the Halcro I think is a little too analytical sounding. It's too clean and sterile. Like wearing a condom every time you listen to music. I would rather get down and dirty with the Krell.
I am in the hunt for a ksa-50
Does anyone know what the difference between the ksa-50 mk i and the mk ii models?

If you are looking at the KSA50 I strongly urge you to also look for the comparable Threshold SA50. An original Nelson Pass design it usually is less expensive than the Krell and just as good; some say better but I suspect they are Threshold owners and biased. I've owned several Threshold products and, were I to go solid state again, it would be Threshold and/or Spectral. The used Threshold presents a wonderful value. Used KSA50 is a pure class with 50 watts that work down to 2 ohms or less easily. They typically trade for around
800 used.

There is a guy at the Audio Asylum forum (Abe Collins) that has an Ksa-50...It my be the mk-2 but I'm not sure.

Anyway, I read a post of his the other day that stated he may replace it because it is to large to fit into a cabinet and he wants soom floor space.

It would not hurt to shoot him an a search at that forum for his e-mail address. He may or may not be selling the Krell but at least will know you are interested if he does sell.


I already found a KSA-50 mk i for sale, but i am wondering if i should wait to get a mk ii amp, which is why i would like to know what the difference between both models is.
Yuri, Read the reviews in Stereophile on line about the KSA 50S - they describe the differences between it and the original KSA. It seems that the reviewer thought that the original was a warmer and more rounded amp, more musical if you will. The KSA 50S was a bit more hifi (my terms). Anyway, read it.
Yes, i did read the reviews of the KSA-50 vs. KSA-50S.
But those are two completely different amps.
I am trying to find out the differences between the KSA-50 Mark I and KSA-50 Mark II models.
C123666: Abe Collins owns a Krell KSA-50S, which is not what i am looking for. I am looking for the original KSA-50 mk ii.
Thanks anyway.
My recollection is that the Mk II had some changes made to it to make it more stable--I think if you shot an e-mail or made a call to Krell they could probably tell you pretty quickly.
Trust me....You want a MKII model.... The difference between the threshold and the KSA-50 might be as simple as you can still get the KSA-50 repaired. I dont know if Threshold is still around, or if they would have replacement parts. The Sony V-fet amps are great amps, but try to find a replacement output transistor for them. You are out of luck.

That is the beauty of buying an older Krell or Levinson.
I owned a Krell KSA 50 in the early 90's, bought used from Walt Bender's AudioMart. Sorry to hear about Walt's passing - may he rest in peace.

The KSA 50's circuit toplogy is a simple layout which incorporates excellent quality components.

It's sound is neutral in that it doesn't seem to add anything to the music. Live radio broadcasts played through the Krell and a Levinson ML-6A preamp, via some of the tuners I owned back then, including Marantz 10B, Day Sequerra Studio and Naim NAT 01, were absolutely stunning.

As good as anything I have heard from master tape or LP.

The Krell was one of those special audio components that really stands out in this hobby, and still rivals the best amplifiers ever made.

You may get amp's that are more powerful, but few that sound any better.

Moreover, while the Krell KSA 50 is one of the best sounding solid state amp's ever made, it doesn't have the lush midrange of good tube amplifier.

For example, my Quicksilver 25 watt monoblocks have a better midrange in this respect, while lacking the overall dynamics of the Krell KSA 50.

I have never found a solid state amp regardless of price, that can match the lush midrange of a good tube amp.

The KSA 50 is one of the few pieces of gear that actually approaches this type of midrange, along with other amps of the era such as the Classe DR-2, DR-3, Bedini 25, and Electrocompaniet 25 and series II amplifiers - each of which has established a loyal and cult-like following.

In retrospect, having owned each of the above, I actually regretted having the KSA 50 and an old Classe DR-3 VHC pure Class A bias amp from the early 1980's the most.

The DR-3 VHC was assembled like a fine Swiss Watch, that to this day easily ranks as one of the best sounding amplifiers this author has ever heard - (albeit a bit dark) - regardless of price.

As for the KSA 50, several audio reviewers had opined at the time this amp was first offered, that the KSA 50 would become a classic, and it certainly has done so.

The challenge nowadays is finding an owner who'll part with their KSA 50.