Krell KSA 50 PCB

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#5,765
But did ya'll see the case? Very nice completely finished case... Would the heat sinks work for the KSA-50 klone?



I have 2 kits left to send out. Both OCONUS. But I am shipping all OCONUS kits FedEx Priority air so they will arrive in 2 -3 days after shipping.

It was brought up that C104 and C109 in the JAN kits may be incorrect.

"C104, C109:

I looked on the BOM you had made, and checked the DigiKey site to reference your order. You had ordered 0.1uF caps, but I "think" I have 0.001uF caps. I also looked at LGreen's pics of his boards, and they are marked "100J100." The caps I have are marked "1n0J100." I also tried to verify with my meter, and it showed <1nF."

I have been very busy and have not investigated the matter further, but hope to do so tonight or tomorrow.
 
#5,767
That thingie is made by former norwegian/swedish co. Transduktor/Ulveco, now Toroid!
Click to expand...

Yea, Uncle Lars does make some nice stuff. I also have his toroids powering my Aleph 2's. BTW: why are they a former Norwegian/Sweedish company and not a current one?




And Just For Jacco......:drool:

:att'n:"Toroids With A Sprinkle Of Toroidial Inductors ":yes:

Mark:joker:
 

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#5,768
Mark A. Gulbrandsen said:


BTW: why are they a former Norwegian/Sweedish company and not a current one?

Mark
Click to expand...
That's an interesting question, but related to the now well established practice in busines where everyone is constantly gobbling up each other.....

The company started in the very early 70ies, and I remember buying directly from the original co. Norsk Transduktor in 74. while still in college.

Some years ago it was gobbled by Toroid, an international consortium. Two years ago this was gobbled by Noratel, a well established norwegian co. in transformers and power electronics. This co. .is owned by Ferd Private Equity Fund, a norwegian lead investment and holding co.
 
#5,769
Mark A. Gulbrandsen said:


Yea, Uncle Lars does make some nice stuff. I also have his toroids powering my Aleph 2's. BTW: why are they a former Norwegian/Sweedish company and not a current one?




And Just For Jacco......:drool:

:att'n:"Toroids With A Sprinkle Of Toroidial Inductors ":yes:

Mark:joker:
Click to expand...

Geographically Jacco and I are not far apart from each other so I'm feeling the same pain when looking at those trannies :bawling:

Regards
 
#5,770
pinkmouse said:


Well, I won't say we don't need the cash, 'cos we do. 🙂

But if you really made $300, then I think there are a couple of people that deserve a bottle of wine or box of chocolates in our own little cloning gang, i.e. Jan, who got us going to start with, and Troy, who's been sweating over the component kits for the last 6 months. 😉
Click to expand...


The cost to Troy was mental not monetary... 😱

The BOM's were soooo close with the tiniest of differences that I stressed tremendously.. I now have gray hair in places I DIDN'T have hair!

Please excuse my terrible sense of humor since, uh since, .... Ok well there is no excuse; I just have a terrible sense of humor.

I wrote the guy with the 2K toriods and asked him for a price on 4 of those chassis for my self and repute. I need 2 (one for Krell KSA-50 and one for Pass Mini-A / A30) and I am hoping they would be able to cope with the heat of the krell...

Anyone care to comment? As was mentioned earlier, 55* @ 100W... Isn't that what the Krell does? 100W? Or is that a reference to the AC disapation which is ~ 250 -300W?
 
#5,772
So I got this 2 KVA toroid sitting here and no idea what the color code on the leads means. I certainly DON"T want to damage this baby!

This is obviously a dual primary/dual secondary transformer. One set of leads is black, brown, and blue. Another set is white,gray, and orange. I assume these are the primary leads as they are also smaller guage wire. The other two pairs of leads are color coded both the same.... red,orange, and blue and are easily twice the guage of wire.

Can I assume the below statement....?

That the primary 120 volt leads are the black and brown and orange and white? The 100 volt taps are the blue and gray?

That the center tap on the secondaries are the blue leads and that the red and orange are the secondary windings on each side of the center tap(blue wire?)?

Don't know if there is an international color code on this......

Thanks!

Mark
 
#5,773
Mark A. Gulbrandsen said:
So I got this 2 KVA toroid sitting here and no idea what the color code on the leads means. I certainly DON"T want to damage this baby!

This is obviously a dual primary/dual secondary transformer. One set of leads is black, brown, and blue. Another set is white,gray, and orange. I assume these are the primary leads as they are also smaller guage wire. The other two pairs of leads are color coded both the same.... red,orange, and blue and are easily twice the guage of wire.

Can I assume the below statement....?

That the primary 120 volt leads are the black and brown and orange and white? The 100 volt taps are the blue and gray?

That the center tap on the secondaries are the blue leads and that the red and orange are the secondary windings on each side of the center tap(blue wire?)?

Don't know if there is an international color code on this......

Thanks!

Mark
Click to expand...


orange and brown were 107 volt colors back when I was an electrician...

My guess is:
white and black are 117V
orange and brown are 100V
and blue / gray 220V

HOWEVER:

white(Neutal) and black(hot) are current US standards for 117V Blue(neutral) and Brown(hot) are current UK standards fo 220V

So your guess is as good as mine. You can use an Ohm meter to find the matching ends and then the highest resistance coil should be the highest voltage.. BIG assumption there... 🙂
 
#5,774
Mark,

I sent an email to the seller... prolly no replay as you would have tried it already. Will keep you posted regardless.

Question: Can the 100v tap be practically used with regular 120v mains?

i.e. upping the sec voltage to about 45vdc. or 34vac-0-34vac
 
#5,777
No problem Mark!

I just got my heatsinks last week as well - they are gold anodized - 12Lx5Wx5H with 14 ribbed fins each. Problem is the fins run the length not the width. I will most likely cut them to 6" lengths and flip them upright.

Do any of you thermal dynamic guru's use a rule or equation to determine ideal transistor placement on heatsinks?


Thanks,
Brad
 
#5,780
It turns out that this transformer is a 1.240 kva unit... still much larger than the seperate 400 va units that were used in the original KSA-50's but not 2KVA as advertised.

Got mine in and running just fine with the help of that spec sheet from Googler. Sound quality to me is much better than it was with the 400 VA units... especially the bottom end. I ended up with +/- 38 volts under load... I ran each primary's hot lead through a CL-60 inrush limiter to keep the fuses behaving. With out the CL-60's the voltage would probably be about +/-39 volts DC.

All in all this tranny is a steal.... grab em up boys!


Mark
 
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