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Old 24th September 2006, 02:50 AM   #131
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Man, that was fast... I don't think it took you 5 min to reply...

Thanks!

Mark
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Old 24th September 2006, 03:49 AM   #132
jwb is offline jwb  United States
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Glad to have been of service. By the way, I have piles of leftover parts from that project if anyone from this project feels like getting a good deal. I have 2SA970, 2SC2240, 2SA968, 2SC2238, 2SJ174, 2SK170, plus lots of low noise passives etc.
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Old 24th September 2006, 04:35 AM   #133
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Default Supply Rails

Quote:
Originally posted by Mark A. Gulbrandsen
...Yesterday we had the opportunity to compare my KSA-50 MK-2 Klone to Bill WW's Krell KST-100 Class A-B amp. Clearly the KSA-50 clobbered the KST-100 in high frequency end of things... it was much more refined while the Krell KST was colder fomr about 5K up and just a tad bit gritty sounding. HOWEVER... the KST-100 blew the KSA-50 out of the water in the low end department driving my Dynaudios with a slam factor that never seemed to run out...

post 30...I believe the rails of the KSA-100 are at +/- 48 to 50 volts...
Mark, thank you for this report. Could you please describe the power supplies of each amp used in comparison(rail voltages, uF, VA of XFMRs) It would povide another layer of background for me.

Secondly, can someone verify the rails of the orriginal? Would there be some play with the +- of the clone and what would be typical low and high of these rails without changes to the circuitry?

I missed the KSA50 and now I know why.

Cheers,

Shawn.
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Old 24th September 2006, 04:45 AM   #134
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Default KSA 100 vs KST100

I read the KSA-100 was of 80's vintage & the KST-100 was of 90's vintage.

Is there debate as to which model will be selected for the clone. Perhaps obviously the KST because it was newer? Just asking as I find myself stumbling over the varoius model numbers a little as I follow the thread.

Cheers,

Shawn.
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Old 24th September 2006, 05:05 AM   #135
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Hi Tom,

Were doing the KSA-100 Mk-2 version or the last version of that amp. At the amp shootout we compared my KSA-50 Klone to the KST-100. Needless to say the KST 100 had incredible low end response and quite decent mids and highs. Everyone there agreed that the KSA-50 does easily beat out the KST-100 in the mids and highs. The 50 has a much warmer sound to it... more tube like. The KST-100 is fully balanced and would be difficult to build... at least as difficult as kloning the KSA-80 as JWB did. The power supply in my KSA-50 Klone is based around a 2KVA toroid with dual secondaries. There is a simple bridge and 56,000 mf per rail. The original 50 had dual trannys that were I'm pretty sure around 400 kva each, Yes, my 2kva toroid is way overkill but it was only 70 bucks. I'm not sure what the supply is in the KST because everything is under one large PCB. I'm sure its pretty beefy though. Let me know if you need any more info.

The photo is of the top of the KST-100......

Mark
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Old 24th September 2006, 11:41 AM   #136
PWatts is offline PWatts  South Africa
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The original used +-52VDC rails, dual 1kVA toroidals and 55000uF 80V electrolytics per rail per channel (not sure about the capacitance).

@Mark: How do you sink a TO92 package? Or should the harder to find DPAK package rather be used? I'm still thinking more in the line of the IRFD110/9110. They have a bit larger package and has more or less the same capacitance as the Zetex ones. Plus they're easy to parallel if needed. Check them out if you like.

I've never used the output stage boards (always used TO3 cans), but will increase the copper area. Compared to the boards used on the original for the TO3's I don't think Al's was lacking, but why not add extra conductivity.

Regarding LTP closeness, there are some very nice integrated packages from Intersil if memory serves that will help layout. I'll take a look at them again, provided they're not too hard to find.
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Old 24th September 2006, 11:57 AM   #137
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Aavid / Thermalloy make at least two slip on TO-92 sinks. Digikey stocks them. One is .42 and the other is $1.30, so thats not a problem.

As for the outputs there will have to be a board that will accomodate both TO-3 and TO-3P to effect any group buy... or two seperate OP boards done up. I also prefer TO-3's myself but the majority out there can't work with them or can't get them. I have no problem with adding the extra copper.....

I've never been a big Intersil fan... they seem to let things go obsolete way too fast.

Mark
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Old 24th September 2006, 10:39 PM   #138
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Here's a 5 device T03 output board if it's any use.
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Old 25th September 2006, 04:34 AM   #139
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Late night surfing...I tripped over this image on google. Another take, I guess.

Cheers,

Shawn.
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Old 25th September 2006, 04:48 AM   #140
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I took a look at it... Thats defiately NOT the Mk-2 version. You can build that amp on the KSA-50 baords that Pinkmouse did.

Mark
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