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Krell KSA 50 pcb
Krell KSA 50 pcb
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Old 4th December 2011, 02:48 AM   #8321
john65b is offline john65b  United States
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The IVa has the ribbon tweeters that really make a difference, I think the IV had a quasi ribbon tweets...

Why bother buying a KSA-80, lets just clone it! The output devices and raw components probably are much better now than on the original KSA-80
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Old 4th December 2011, 02:59 AM   #8322
Mark Allen is offline Mark Allen  United States
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Yea... I have the gerber data to make those boards if you don't have it. Lots of complicated transistor matching to do for that amp and the fets are also hard to get. PCB's would be fairly costly per set... Modding an existing amp would be far easier... Typically 1200.00 to 1800.00 to buy and oh that nice metal work Krell did for those amps that would cost as much as a complete used amp to duplicate. Making a KSA 160 out of a KSA-80 is very easy and KSA-80's are more common.

Mark
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Old 4th December 2011, 03:06 AM   #8323
john65b is offline john65b  United States
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Default KSA

There are a pair of KSA-160s on Agon now. $3900 (ouch)

I have a gutted KSA-300 chassis that I am planning to put a pair of KSA-50 amps into, or a ICEPower module with the KSA-50 for biamping. That chassis went thru hell and back when I got it (amp literally burst into flames with previous owner) - sandblasted it and anodized it black a year ago...
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Old 4th December 2011, 03:10 AM   #8324
Corvus corax is offline Corvus corax  United States
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I was fortunate to have a nice KSA 80 fall into my lap a few years ago. It sat neglected for a while, after it started popping and thumping loudly in one channel. After letting it lay idle for a year or more, I brought it into the factory with me one day, and had one of my techs look it over (I am too lazy to get in there myself…). When he opened it up, a bunch of micas came falling out like discarded termite wings. All the plastic fasteners holding the driver and bias transistors to the common heat sink had crumbled, and some of the parts were leaking to the blue metal strip that serves as a heat sink.

We replaced the errant hardware and insulators, and the noise was gone. I haven't reset the bias- the amp is running a little cool at the moment, and one channel is slightly cooler than the other. But it still sounds excellent!

I have a pair of driver boards partially built up to replace these if they ever go South… but they will probably end up going into a new amplifier one day.
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Old 4th December 2011, 04:28 AM   #8325
a.wayne is offline a.wayne  United States
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Quote:
Originally Posted by john65b View Post
KSA50 Pinkmouse's board, 3 pair 2SA1943/2SC5200, Biased to 650mv across .68ohm emitter resistors, 36VDC rails...so a biased up a little more than the KSA50,
Are the Jim audio KSA100 boards on fleabay good ...?

Quote:
Originally Posted by john65b View Post
The IVa has the ribbon tweeters that really make a difference, I think the IV had a quasi ribbon tweets...

Why bother buying a KSA-80, lets just clone it! The output devices and raw components probably are much better now than on the original KSA-80
Lead ..... follow ...

Quote:
Originally Posted by Mark Allen View Post
Yea... I have the gerber data to make those boards if you don't have it. Lots of complicated transistor matching to do for that amp and the fets are also hard to get. PCB's would be fairly costly per set... Modding an existing amp would be far easier... Typically 1200.00 to 1800.00 to buy and oh that nice metal work Krell did for those amps that would cost as much as a complete used amp to duplicate. Making a KSA 160 out of a KSA-80 is very easy and KSA-80's are more common.

Mark

True , then you still have to go thru and refurbish the amp... added cost ..


For what it's worth Agostino did tell me he will service Krell amplifiers if need be , just contact him at his new gig ..

Regards,
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Old 4th December 2011, 11:45 AM   #8326
john65b is offline john65b  United States
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Quote:
Are the Jim audio KSA100 boards on fleabay good ...?
I have never dealt with Jim Audio's KSA100 Boards, haven't heard anything bad....

Quote:
True , then you still have to go thru and refurbish the amp... added cost ..
Price to refurb a unit would be quite costly...

Quote:
For what it's worth Agostino did tell me he will service Krell amplifiers if need be , just contact him at his new gig ..
Not to nit pick, but its D'Augustino, not Augustino, correct?
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Old 4th December 2011, 12:36 PM   #8327
dr.strangelove3 is offline dr.strangelove3  Netherlands
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Quote:
Originally Posted by a.wayne View Post
Are the Jim audio KSA100 boards on fleabay good ...?
FWIW, I have a pair of jims KSA-100 boards. Very nice boards, highest of quality. If I remember correctly there is an error on the silkscreen somewhere, a diode or cap printed reversed or something. They are a little larger than an original board, but otherwise the layout of the pcb is almost a carbon copy of the original.
I have not build anything with the boards and have not examined them very closely, so I don't know if there are other problems with the boards.

If you like I can send you the BOM and schematics I received from jim when I purchased the boards.

Regards
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Old 4th December 2011, 12:41 PM   #8328
jacco vermeulen is offline jacco vermeulen  Netherlands
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Originally Posted by john65b View Post
correct?
September two years ago it was Marchino.
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Old 4th December 2011, 12:45 PM   #8329
VT67 is offline VT67  Belgium
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The Dutch guys are still active here!?

Walter
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Old 4th December 2011, 02:40 PM   #8330
pinkmouse is offline pinkmouse  Europe
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Krell KSA 50 pcb
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