krell ksa5 klone

[kevin gilmore]

stereo board

http://gilmore.chem.northwestern.edu/ksa5stereo.jpg

 

may put an alpha pot on it depending on what people want.

 

10 x 7.5 inches.  Slightly smaller than the original.

Edited December 2, 2012 by kevin gilmore

[Horio]

Nice. Does this amp require much if any matching of parts?

[Inu]

I think R20 (Pot) is 50ohm.

[kevin gilmore]

The picture says 500R.

will check the detailed pictures later.

[Inu]

Sorry, you are right.

500R = 500ohm.

500 = 50ohm

[kevin gilmore]

please someone (everyone) verify the board vs the schematic

 

http://gilmore.chem.northwestern.edu/ksa5.pdf

 

http://gilmore.chem.northwestern.edu/ksa5.jpg

[Inu]

Schematic:

Q2(Q7) Collector -  Q12(Q13)Base

Board:

Q3(Q8) Collector - Q12(Q13)Base

 

IN2 only (IN1 is OK)

Schematic:Q14,23&24 MJE15030 

Board:MJE15031

 

Schematic:Q25&26 MJE15031

Board:MJE15030

 

+/-22V line (or +/- 21V?)

4.7uF/63V are not on the schematic

 

Q27 Collector

0.1uF is not on the schematic

Edited December 5, 2012 by Inu

[kevin gilmore]

Thanks, got all of them. Not sure yet about q27 collector cap.

The 4.7uf caps are at birgir's idea. (also kind of expensive)

evidently no amp is complete without some wima's.

will post again when i get home.

[spritzer]

One likes his film caps... 

[kevin gilmore]

updated schematic and picture, have a look.

 

very pathetic BOM in progress

includes some of the power supply

 

1000uf 35v ls=5 dia=13mm 871-B41041A7108M000 35 0.47 16.45
.1uf 100v ls=5mm 80-R82EC3100DQ70J 14 0.32 4.48
4.7uf 63v wima 505-MKS24.7/63/5 7 4.33 30.31
470pf 500v  ls 5.9mm 5982-15-500V470 4 2.28 9.12
39pf 500v ls 5.9mm 598-CD17ED390JO3 2 1.35 2.7
220pf 500v ls 5.9mm  598-CD15FD221JO3F 2 1.22 2.44
    
220uf 50v ls 5mm dia 10mm 647-UPW1H221MPD 4 0.58 2.32
4700uf 50v ls10mm 35 dia 598-SLP472M050C5P3 2 3.2 6.4
    
mjf15030  6 1.63 9.78
mjf15031  4 1.63 6.52
heatsink amp board 513102b02500g 8 1 8
mpsa56  19 0.12 2.28
mpsa06  23 0.32 7.36
lsk389  2  
relay 653-g5v-2-h1-dc24 2 2.76 5.52
op27 digikey 4 6.01 24.04

 

Its about $137 not including the resistors and some of the

other power supply components. So definitely under $250

with transformer and everything.

 

Unless you go very nuts on the resistors.
 

Edited December 6, 2012 by kevin gilmore

[Inu]

Zettler 24V Relay

A2830-2C-24DS

http://www.bgmicro.com/REL1086.aspx

MPS8099 and 8599 (0.15)

http://www.bgmicro.com/TRNMPS8099.aspx

http://www.bgmicro.com/TRNMPS8599.aspx

 

 

It is hard to pairing MJEs…   

 

MJE15030G(NPN)

Lot:AFA50

hfe = 78 78 80 83 96 97 98 104 104 105 107 109 111 114

 

MJE15031G(PNP)

Lot: AFB09

hfe = 228 234 238 241 242 252 253 257 260 262  

Edited December 7, 2012 by Inu

[fishski13]

thanks Kevin and Bigir for this.  i'm in for a few boards.

[spritzer]

The amp board is just about ready so I'll probably be ordering prototypes before Christmas.   

[fishski13]

The amp board is just about ready so I'll probably be ordering prototypes before Christmas. 

 

sweet!

[kevin gilmore]

what we need to do is find a massive stock of 1000uf/25v blackgate non-polarized caps.

 

The only place that has them in stock wants $80 each and we need 35 per board.

Edited December 7, 2012 by kevin gilmore

[c12mech]

what we need to do is find a massive stock of 1000uf/25v blackgate non-polarized caps.

 

The only place that has them in stock wants $80 each and we need 35 per board.

 

Soooo...for about 10x the price of the amp I could have it all Blackgated up? :blink:

 

Even if I wanted to go nuts with it, there is no way I could pull the trigger on that.

[spritzer]

Yeah sane thing here.  I'll just stick with the Panasonic's and waste the rest of the money on the Megatron PCB heading my way...

[deepak]

If only these were in stock... you could have an amp the size of a mini fridge

 

http://www.mouser.com/ProductDetail/Kemet/C4EEHNX7100BAUK/?qs=sGAEpiMZZMv1cc3ydrPrF%252b30hQTSgFpptXtXdwWwAIk%3d

[kevin gilmore]

35 of those are bigger than a mini fridge.

[spritzer]

I still think Krell just had a few thousand of those CDE caps sitting there and decided to cram the amp full of them...

[bozebuttons]

Origional caps where Sprague,Krell must have had stock in the company.

[trident900fi]

I just order all the components and the PCB to make one

I will use Nichicon FG series for the 1000uF/35V condensators. Great value for the money... Not so good as the Blackgate or Elna Silmic II, but much cheaper !

I Let you know if the name of Krell is as great as it should be

[Bidoux]

I know the goal here is to clone the krell but I am curious ; would it work to split R15 and put an integrator's output in the middle, dynalo style ? Requires to modify the servo and get rid of C10, C18 and C19 ...

[spritzer]

Some progress:

 

 

I didn't order the PSU boards as they were never 100% finalized.  A Sigma22 works just as fine for testing though. 

[Nebby]

Very cool spritzer! I'm definitely looking forward to seeing how they work out