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Old 18th October 2004, 09:01 PM   #41
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I have been seeing quantities of the A42 and A92 transistors on Ebay!

I am looking for the W42 and W92 versions however.

What is the difference between the A & the W versions????


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Old 18th October 2004, 09:06 PM   #42
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Default Zero Cool

Frankly I don't know
However I'm sure somebody "out there" can tell us

Normally I use the MPSA's for almost all my project as they are cheap, realiable and I like the sound they produce
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Old 18th October 2004, 09:40 PM   #43
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Jan, Pc = colector dissipation. 15032 / 33, which have Pc = 50 W are not on this position optimal, 42 / 92 are better .
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Old 18th October 2004, 10:05 PM   #44
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Just a comment or two.

The lack of V-I limiter is what makes Krell a Krell. As is, the 'clone' would not be able to do what Krells become famous for - drive insane loads (Apogee Scintilla and like) without compression.

I've never seen an output coil in any of the Krell amps - I doubt it is needed.

All Krell amps from that vintage I've seen had input low pass at around 350kHz or so, hence C101 should be calculated as such.

Despite ridicule from some, KSA50 will whip the pants off most of todays amps with ease, and sound MUCH bigger than its 50W rating suggests.
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Old 18th October 2004, 10:18 PM   #45
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Quote:
Originally posted by Bratislav
Just a comment or two.

The lack of V-I limiter is what makes Krell a Krell. As is, the 'clone' would not be able to do what Krells become famous for - drive insane loads (Apogee Scintilla and like) without compression.
.
Hi Bratislav, Don't overlook the transformer(s).......
Any specs on that?
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Old 18th October 2004, 10:59 PM   #46
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What's a V-I limiter?

Another Krell from 1989 has a low-pass at 250kHz on the input.

Edit: I found the answer at http://sound.westhost.com/vi.htm
Edit: Also the KMA-160 does have diodes to prevent the signal from swinging outside the rail voltage, but no active V-I protection that I can see.
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Old 18th October 2004, 11:04 PM   #47
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Quote:
Originally posted by Elso Kwak

Hi Bratislav, Don't overlook the transformer(s).......
Any specs on that?
Yup, FeO3Kr2 (Ferro-Kryptonite) core with 0.00001% regulation

BIG and HEAVY comes to mind ...
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Old 19th October 2004, 06:42 AM   #48
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Pavel:
Thanks for correcting me
I must learn not to read and write when I'm tired

Bratislav (and others):
The V-I limiter was put in as an additional options for those who would like some kind of protection.
Don't like it ??? Don't use it

The output coil are shown in the schematic for those who will build this amp with new high freq. transistors....
I'm not sure how it will respond to modern components, so better be safe than sorry
And again: Don't like it ??? Don't use it

Please keep the comments comming
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Old 19th October 2004, 06:45 AM   #49
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Cool Transformer Specs

Quote:
Originally posted by Bratislav


Yup, FeO3Kr2 (Ferro-Kryptonite) core with 0.00001% regulation

BIG and HEAVY comes to mind ...
Hi Bratislav,
I was quite serious........

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Old 19th October 2004, 07:20 AM   #50
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Default Re: Transformer Specs

Quote:
Originally posted by Elso Kwak


Hi Bratislav,
I was quite serious........

The quality of transformers in Krell amps I've seen (heard) varied quite a bit. Some were dead quiet, some had quite a buzz.
All were generously specified (more than enough VA to run at rated power even at low impedances). As far as regulation and flux density I woudln't have a clue, I only had one specimen to look up closely(ish), and at 3KW it was reasonably good as far as sagging (<2% I think), but then most big trafos are.
I don't think they were special devices, despite impressive logos on them :-)
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