Krell KSA 50 PCB

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#5,282
lgreen said:
K-Amps,

Measure the resistance between secondary windings with an ohm-meter. You will be able to tell which wires are on the same secondary, and if there is a center tap, its resistance will be 1/2 that of the upper and lower taps. If there are dual secondaries the wires from each will be open circuit on the ohm-meter allowing you to identify them as not connected.

You should be able to do this and if you write down all your readings it will make sense and you will see how easy it was.
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Lgreen,

My guess is that there is NO centertap. You have to make one by taking the + of one with the - of the other. If they were 4 wires, that would be easy to do.

8 wires makes it complex exponentially. but keep those good thoughts coming.


🙂
 
#5,286
K-amps said:


Lgreen,

My guess is that there is NO centertap. You have to make one by taking the + of one with the - of the other. If they were 4 wires, that would be easy to do.

8 wires makes it complex exponentially. but keep those good thoughts coming.


🙂
Click to expand...

I see your point, you could always connect a signal generator to them and measure the AC voltage with a DMM. Output something at 60Hz from you soundcard or something.
 
#5,288
lgreen said:


I see your point, you could always connect a signal generator to them and measure the AC voltage with a DMM. Output something at 60Hz from you soundcard or something.
Click to expand...


Yes, I guess I am back to connecting it to the mains and load testing it to get the right wires. 😡

I will probably begin with a series 100w lamp on the primary side to begin testing the secondary voltages for any two wires, once I get the 67vac pairs, I will load them up 1 by 1 with a 30 ohm resistor and see if it can mantain 64-65vac on that winding using a 10-15A fuse instead of the 100w lamp. At least that's the plan till I hear one better, or if someone has the schematic.
 
#5,289
I'm a little confused. If the wires are all the same size and color, what good will a schematic do? How would it be able to tell you which wire is which. I really don't understand why they would make the transformer that way. Just doesn't make sense to me that the wires aren't at least different colors, but I would think they should be different sizes.

I don't understand what is difficult about hooking up the primaries and just measuring the secondaries. I have done that on every one I've used so I could find which pair to use for the center tap.

Blessings, Terry
 
#5,290
still4given said:
I'm a little confused. If the wires are all the same size and color, what good will a schematic do? How would it be able to tell you which wire is which. I really don't understand why they would make the transformer that way. Just doesn't make sense to me that the wires aren't at least different colors, but I would think they should be different sizes.

I don't understand what is difficult about hooking up the primaries and just measuring the secondaries. I have done that on every one I've used so I could find which pair to use for the center tap.

Blessings, Terry
Click to expand...

Mind emailing me a picture of your Toroid? better yet, showing the connections?

You are right , I have no clue why he set them with same colors. If you look at the auction picture (I cant shoot one of mine as I am not in town) you can see the 4 blues and 4 greens all same gauge.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7540258796&sspagename=ADME:B:AAQ:US:1

I suspect he sent me a quad 33 or Paralelled dual 66



The schematic might tell me how the consecutive wires (regardless of color code) are wired, which would make figuring it out easier.

TIA.
 
#5,291
I don't think I have a schematic but I can look at the transformers I have and see if I can make sense of it. My Trans for the AlephX is a quad, all the same color, but they are all the same voltage. I can at least tell you how they pair up though once I get home and pull the cover off.

Blessings, Terry
 
#5,292
Hi K,

OK I looked at my 4X12 1KVA transformer. It has 8 yellow wires coming out of the secondary. They basically go from right to left;
0V,12v,0v,12,0v,12v,0v,12v. So for dual channel I connected the first and third wires together as a center tap and the second and fourth wires to the bridge. Same for the second set.

My guess is that yours is set up the same way except that green represents one voltage and blue that other. At least I would suppose that if the green all exited the transformer side by side as well as the blue. It should be very simple to confirm which set were the 12V and which were the other.

Blessings, Terry
 
#5,293
Now KSA-50's can be had for $650-700 on eBay.
Click to expand...

I don't think so. I've been watching E-BAy and Audiogon clocley the last year and you'd be lucky to get one for a grand. And they seem to go fast when they do come up. I've got to wonder if this thread hasn't pushed the value of them up on the market a bit.....


What about using someone else's PCBS to implement the circuitry like we all have done? Edit- all except maybe 2 or 3 of us.
Click to expand...

If you go back through the threads during the last board design you will find that most of us had conributed suggestions and or had a hand in the design of the board. Ditto with Jan's board. Its a family effort here in many aspects.


Mark
 
#5,295
still4given said:
Hi K,

OK I looked at my 4X12 1KVA transformer. It has 8 yellow wires coming out of the secondary. They basically go from right to left;
0V,12v,0v,12,0v,12v,0v,12v. So for dual channel I connected the first and third wires together as a center tap and the second and fourth wires to the bridge. Same for the second set.

My guess is that yours is set up the same way except that green represents one voltage and blue that other. At least I would suppose that if the green all exited the transformer side by side as well as the blue. It should be very simple to confirm which set were the 12V and which were the other.

Blessings, Terry
Click to expand...

Thanks Terry, (and Lgreen and Troy and our good friend Stuart).

This helps!


🙂

blessings,

Arif
 
#5,296
Mark A. Gulbrandsen said:


I don't think so. I've been watching E-BAy and Audiogon clocley the last year and you'd be lucky to get one for a grand. And they seem to go fast when they do come up. I've got to wonder if this thread hasn't pushed the value of them up on the market a bit.....

Mark
Click to expand...

I think this thread HAS pushed up the value. 😀 I sold my KSA-100mk.II a bout a year ago for $950 after relisting it twice... the KSA-50's were going for $650-700 at the time.
 
#5,300
“Are there any spare parts kits?”

Hi xxx-

There will be 5-7 channels of parts left when I finish sending out the GB parts.

HOWEVER!! We are still awaiting 3 parts from Mouser. The 5 watt output resisters, the 820 Ohm resistors and the 2 watt resistors.

Once those arrive I will be shipping out all the kits. After that I will inventory what is left and offer the remaining so it will prolly be another week or two since I still haven't rx'ed the last 3 components.


Thanks again,

Troy

I called Mouser yesterday (03 Jan 06) and ask for an expected date for delivery. They said they had to contact the manufacturers and I have not heard back from them yet.

I am VERY sorry for geting everyones hopes up. I spent the 3 day New Years weekend test fitting parts and seperating the recent arrivals. I could not find 3 pieces so I went back to the receipts and web orders, and sure enough 3 items were back ordered and still have not come in.


EDIT:

WEB shot.

Mouser
Part # Mfr.'s
Part # Manufacturer
Description
Your Part # Qty.
Pending Price Ext. Status Date Mouser
Invoice #
71-RN60C8200D RN60C8200D Vishay/Dale 1/4WATT Metal Film Resistors
1/8watt 820ohms
JAN R125 100 $0.220 $22.00
71-CA000225R00JB14 CA000225R00JB14 Vishay/Dale Power Wirewound Resistors
2WATTS 25OHMS 5%
JAN R127R8 150 $0.250 $37.50
588-TUW5JR68 TUW5JR68 Ohmite Ceramic Housed Resistors
5watts 0.68ohms 5%
JAN RE1R2R3X2 300 $0.330 $99.00
Sub Total: $158.50
 
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