Krell KSA 100mkII Clone

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#2,062
Re: Silkscreen

bobgroger said:
Have not heard back from Mark yet regarding his wishes for funds distribution. I have about $235 in my paypal account currently.

Bob G.
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Keg party!!!!!! 😀

Actually I think Mark should be reimbursed for his expenses of getting the boards, you should be compensated for taking over the distribution and the remainder given to DIYAudio which makes all of this possible.

I had more than $200 left from the KSA-50 clone PCB GB and gave it back to the forum. It's what enables this site to exist.
 
#2,063
As I intend on using more output devices and lower value output resistors than the original Krell, I needed to know how to work out the value of the driver resistors R38, 39, 40 and R41.

As always, Andrew assisted me by emailing me some formulas that I have put into a spread sheet to help ease the calculations.

If I have made any errors please let me know.
 

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#2,067
What are the secondaries for the transformer if I'd like to use separate windings for LTP, driver and output stage? Winding for output stage is pretty obvious 2x38V *11-12A. What about windings for stabilized LTP and driver? According to schematics LTP uses 39V, the rest are 52V or little bit more. What kind of windings should I order for these to have room for proper regulation? Which source should I use for feeding Q5-Q8 - LTP or driver one? What about Q10-13?

Thanks,
Viktor
 
#2,068
transformer electrostatic screen

I'm going to order following transformer:
2* 41V * 12 A
2* 55 * 1A - driver
2* 55 * 0,25A
1* 20 - 1A protection, soft start, etc

How helpful is electrostatic screen? Is it much better then simply connect the outermost layer of primary winding to mains neutral?

I found few available transformers without electrostatic screen, so I want to decide do I want to order a custom one just because of that.
 
#2,069
Hi,
for a custom wind it's probably worth paying the little extra for the electrostatic screen.
What VA and what regulation are you specifying?
Each channel will require one of these transformers.
The 12A winding will almost certainly be bi-fillar wound. Ask them to bring all 8 tappings to the outside. i.e. 4*41Vac@6A
 
#2,070
AndrewT said:
Hi,
for a custom wind it's probably worth paying the little extra for the electrostatic screen.
What VA and what regulation are you specifying?
Each channel will require one of these transformers.
The 12A winding will almost certainly be bi-fillar wound. Ask them to bring all 8 tappings to the outside. i.e. 4*41Vac@6A
Click to expand...

Thanks for fast reply.
I’m specifying 1000VA per transformer and I’m going to build 2 monoblocks. I basically have 2 choices: order custom transformer with electrostatic screen from Victoria Magnetics (I’ve got an approximate quote for $280 for one with electrostatic screen and a can) or buy 2 or 3 separate transformers per channel from Avel for cheaper price but without electrostatic screen. If electrostatic screen give any sonic advantages comparing to properly connected transformer without it I’ll pay extra for custom one.

What is the source of heatsinks for output stage?
I found some on Newark, unfortunately these should be mounted vertically and a bit pricey ($47 each): http://www.newark.com/15J9648/fans-...product.us0?sku=H-S-MARSTON-890SP-03000-A-100
 
#2,074
Re: Silkscreen

Fix said:
If I want to pick up this project... Where do I start ?

Is there any PCB to buy, or they are sold out ?
Who should I talk if there are any left ?



Any help is good, since this will be my first amp project.


Regards
Patrik
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There is a WIKI for this proj: http://www.diyaudio.com/wiki/index.php?page=Add+your+names+join+the+group+buy
Schematics were attached few posts earlier.

Bob Groger has some PCB left as on 2-14-2008
bobgroger said:
... I have 9 gold boards remaining. ...
Bob G.
Click to expand...
 
#2,077
To Bob,

Since I'm a new user I can't send e-mail to you.
Have some questions about the PCB and other stuff about the project.

Please send me a PM or mail.


Else I can post my questions here.


* How much for the PCB

* Is componets included or sold as a kit ?

* Is there any detailed How To Build with pictures ?


Anything else what could be interesting to know before starting the project.
 
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