Krell Shootout In Salt Lake City

[Mark A. Gulbrandsen]

Written by Bill WW live at the shootout......

We compared the Ksa-50, ksa-100, and Kst-100 today.

The Krell KST-100 was no question the winner of the three amps in looks and it helds it own surprisingly well for a class A/B amp.

Mark said it was the best A/B amp he has ever heard.

Now as to the sound of each more specifically.

Initial impression of the Ksa-50 sounded more pronounced in the highs. After extensive listening to the Ksa-100, we decided the Ksa-100 had better highs noticiably with chimes. The ksa-100 really sounded much more realistic than the 50 did on the chimes.

We then compared the Kst-100 to the Ksa-100 and found the Kst-100 sounded closer to the Ksa-100 in sound than the 50 did. The main difference with the Kst-100 was with less bias, it seemed to not sound as spacious. The Kst-100 seemed to mimic the Ksa-100 on the instruments such as chimes, although it did not sound as smooth as the ksa-100. The Kst-100 seemed to not have quite as pronounced highs as the Ksa-100, but it was very close, but slightly less emphasize probably due to less biasing of the Kst-100. It was closer than expected on how similar those two amps sounded though. I figure if the Kst-100 were to be biased up a bit more it would sound very similar to Mark's Ksa-100.

One notable difference between the Kst-100 and Mark's Ksa-100 had to do with his larger transformer in his Ksa-100, which seemed to help in the lows. It was tighter in the bass with more headroom and slam than the Kst-100 with a smaller toroidal transformer.

So, overall the new Krell Ksa-100 is worth building after hearing all three.

The three amps... KSA-100 Mk-2, KSA-50 MK-1.5, KST-100

[Mark A. Gulbrandsen]

Lucky Lyndy on a quick after post note:
Yes, the KSA 100 had extended highs and a wider soundstage, but I still liked the upper middle range timbre (male vocals) on the KSA 50.

Also post script: BillWW wants to add that his commercial KST 100, after two hours of warm-up, sounds a LOT closer to the sound presentation of the KSA-100. Cymbals, and chimes are similar. Mark feels the soundstage is smaller and the banwidth is limited, due to the Class A/B biasing.

[Zen Mod]

where da toobz are?

[Mark A. Gulbrandsen]

where da toobz are?

On da shelf above da amps.....

Mark

[BillWW]

I brought my amp home today and noticed, while looking at the power supply section that it only uses computer grade Malory 13,000 uF 63 volt capacitors.

That would further explain why it sounds a bit harsher than Mark's KSA-100 with higher filtering, aside from biasing.

Bill

[Bratislav]

Silly question ...

You listened to all 3 amps and took notes without knowing which one played, right ?

[AVWERK]

Mark , this is what I came up when comparing the 50 Mono's (PM boards) with
my Synder/Krell 150 mono,s

The 50 does emphasize the mid range because the highs and lows sound somewhat softer overall.
This might be a power issue only, I dunno, but it seems to point in that direction...
But the overall effect of that midrange makes me forget about the electronics and forces me to focus more on the music, it just creeps up on you slowly to great effect
. This amp might have been voiced with the hot top end moving coil cartridges that era had, just a guess on that one though..
but I have to agree with you on that luscious midrange, That's where all the action is with this amp! Very well done!

My Synder version just extends the top and bottom with more space all around with more viseral punch and emphasis at those extremes. It suits more speakers overall with power to spare

Looking forward to those KSA 100 boards BTW!!!

Speakers used (ML SL3's) (original Quad ELS) (Audio Concept's Sapphire II Ti's)

Regards
David M.

[Zen Mod]

Originally posted by BillWW
I brought my amp home today and noticed, while looking at the power supply section that it only uses computer grade Malory 13,000 uF 63 volt capacitors.

That would further explain why it sounds a bit harsher than Mark's KSA-100 with higher filtering, aside from biasing.

Bill

that's certainly s$%ty amp!

sez little fox just after turnin' back to grape ..............

[gerhard]

Originally posted by Mark A. Gulbrandsen
The Krell KST-100 was no question the winner of the three amps in looks and it helds it own surprisingly well for a class A/B amp.
Mark said it was the best A/B amp he has ever heard.

The user manual of the KST 100 says that it runs class A until half power IIRC. Probably it has some sliding bias scheme, seems to be pretty complicated. From the heat it generates in idle state I'd believe it. I've bought a used one some time ago.

Does anybody out there have a circuit diagram of the KST-100?

Gerhard

[BillWW]

Originally posted by gerhard


The user manual of the KST 100 says that it runs class A until half power IIRC. Probably it has some sliding bias scheme, seems to be pretty complicated. From the heat it generates in idle state I'd believe it. I've bought a used one some time ago.

Does anybody out there have a circuit diagram of the KST-100?

Gerhard

If that is the case, Mark was telling me the KSA 100 runs up to 80 Watts class A. That would explain why the KST 100 did not quite sound as nice if the KST 100 was 50 Watts of class A bias.

I would like to find a service manual too, so perhaps I could tweak it to higher bias. I bet it would sound better with more bias. It runs relatively cool at the current bias setting.

Regards, Bill