what krell ?

[musicalbox]

Hi,
I would like to ask you a question. I own a couple of "martin logan quest z" and I would like to know what between the Krell power amplifier of the years 80-90 could do my case. I like the sound transparent, fast, but with sweet and velvet-like highs, and with the famous krell' s bass. I had thought to the Krell ksa 80, ksa 80 b, ksa 150, ksa 250, ksa 100 s ...
Thanks a thousand for your help.


David


ps
Is true that the ksa 150 and 250 sounds more harsh on the highs and the ksa 80b have more tube-like sound?

[Mark A. Gulbrandsen]

I would highly reccomend the KSA-100 Mk-2. I owned a KSA-80B for a number of years and had it on a pair of Sequel 2's but it was just too over defined on the top end, the line stage was a KBL. The Sequels also suffered fomr bounce back waves at high levels that made the panels vibrate. Rear wave absorbtion might be necessary. Also my 80B was alot more equipment and cable fussy than the KSA-100 Mk-2 seems to be. A pair of KMA-100's might be even better. I doubt the KSA-50 has enough current to really make your ML's sing. Also consider one of the 100 WPC+ Pass Amplifiers.

Can't answer on the comparison between the 80B and larger amps in that series but again the 80B power amp was fussy as far as cables and head end. A good tube line stage ala 12B4 might be the best route.

Mark

[musicalbox]

Hi Mark,
thank you very much for your reply .
Have you heard the ksa 150 or 250 ,even on comparison with the ksa 80b?
Thank you!

David

[Mark A. Gulbrandsen]

Nope, Sorry... I have not.

Mark

[musicalbox]

some other has compared the Krell ksa 150 or 250 with the ksa 80b?
Thank you!

David

[ACTIVA]

Hi David,

I used to own the Krell KSA250 with matching KRC2 for more than 10 years before I sold them off in 2005. The KSA150 / 250 are /were similar in sound qualities. In terms of subjective performance, The 150 is a little darker compare with 250, and the 250 had a better drive, slightly more transparence and dynamic capability.

Do take note the KSA150 / 250 were not pure class A biased design like the earlier KSA 80/80B/ KMA160 etc. The 150 / 250 operates in pure class A at up to about 20% of the rated output, ie, 50 watts pure "A" for the 250 and the rest of the output power range in enriched class AB operation. Hence the smaller heatsinks compare with the 80/80B/200B etc. I was told this quasi Class "A" biasing scheme was a last minute decision from Dan D' Agostino as to improve the field reliability issues on the KSA200 / KMA400.

The 80/80B/200/200B were pure class A designs and runs hot. Due to the relative inadequate heat sinkings (No force convection / Fans as the older KSA50/100 etc) the KSA200 / KMA400 did developed field reliability problems and were replaced by the KAS 150 / 250 MDA300 / 500 in a relative short time latter.

The KSA80 / KSA200 / KMA160 were more romantic / sweeter soundings but less transparence and less dynamic compare with the later KSA150 /250 /MDA300 /500 series.

Martin Collom rated the KSA250 a little better than the KMA160 in Hi Fi News / RR in a 1992 review article, AFAIK. BTW I bought the KSA250 before the review.

Hope the information is useful for you.

Regards
Max

[a.wayne]

Interesting topic ,

Anyone here been able to compare the Krell clones KSA50/100 to say the later balanced 80/80B ..

KSA80 schematics : http://www.solaris.no/electronics/po...ll_TECHINF.pdf


Regards,
A.Wayne

[Mark Allen]

Yes, I owned an 80B some years back... very good amp indeed and much more difficult to build, requires matched fets. Many audible similarities to the KSA-100 a bit cleaner top end. I found my KSA-80B to be very dynamic but my Dynaudio speakers are not hard to drive.

There was a short thread on DIY where a guy had a pair of KMA-160's and one I believed had a burned up board. He reproduced the boards and posted all the schametics and restored the amp. If you do a search you might be able to find it. If not I have saved all the schematics and board files someplace on my server and would just need to find them.

Mark

[Arick]

Sorry, I can not help for the sound comparison, however, If you chose the KSA-150 or 250 there are a couple of issues you might want to be aware of.(I own a 150)
First they might have transformer "buzzing" and no replacement is available from Krell for the 150.
Secondly all the caps have to be changed,
Third if you buy one from someone who ran it 24/7, you WILL have a problems with the soft start.
If you need to, PM me for more info.
Good luck, Eric