threshold sl10

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Teake, how did the SL-10 upgrade go? A couple of years back, I replaced all the electrolytics in my SL-10 with Black Gate Standards. After the capacitor change out, this SL-10 was transformed into pure magic in my system. What a difference! I did quick measurements of the old electrolytics that I pulled out, and every one come up different, but guess that's what I should expect for 25 year old capacitors in a unit that was left on for at least twenty of those years! The power supply is next . . .
 
Hi!
here it is Grtz teake.
 

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intense-tavda said:
He Guys!
I also want to upgrade the powersupply of the sl10 with new capacitors and transformer. Do you know what the value of the transformer is? The capacitors are 6900 MFD 60VDC.
Thanks Teake.

Mine SL10 uses a Hammond 166J28 which is a 115V Primary/28V 1A center tap secondary.

I have the same PS caps (Mallory CGS 6900 MFD). These are impossible to find. Due to the PS chassis size, replacement choices are limited. I'm think about building a new supply for mine too. I'll use a larger chassis so I can fit a toroid (Hammond 182J15 30V 1A should work nicely) and make up a board for capacitors.

Regards,
Bill
 
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MashBill said:


Mine SL10 uses a Hammond 166J28 which is a 115V Primary/28V 1A center tap secondary.

I have the same PS caps (Mallory CGS 6900 MFD). These are impossible to find. Due to the PS chassis size, replacement choices are limited. I'm think about building a new supply for mine too. I'll use a larger chassis so I can fit a toroid (Hammond 182J15 30V 1A should work nicely) and make up a board for capacitors.

Regards,
Bill


with toroid of same size you'll not have any benefits-VA rating is almost same and toroid will pass way more garbage from mains in your PSU;
regarding caps-use whatever you can squeeze in original box-with today's cap sizes,I presume that you can fit some 10.000 UF jobies instead 6900.....

on the other hand- if you must change xformer ,why not go with Naim route -use mindless big toroid (say 200 to 500 VA) and crazy amount of caps....I bet that you can find some surplus caps in range
of some 100.000 UF/25V ........

then you can gain SOME benefits ; will you hear it or not,that is question :devilr:
 
Forrestc said:
10,000uF 75v Mallorys in the same form factor as the original caps (2" x 3.125" screw terminal) in the SL10 PS are available from Mouser:

http://www.mouser.com/catalog/625/544.pdf

Their part number is: 539-CGS75V10000S


Thanks Forrest. I've seen those, but I was afraid they were too tall. Max inside height of chassis is 3.25", so I was worried. I went ahead and ordered a pair though to try out. I'll post a follow-up when I get them. If they are too tall, I will just build a new PSU with them.

Thanks again,
Bill
 
Forrestc said:
10,000uF 75v Mallorys in the same form factor as the original caps (2" x 3.125" screw terminal) in the SL10 PS are available from Mouser:

http://www.mouser.com/catalog/625/544.pdf

Their part number is: 539-CGS75V10000S

I just found that the above Mallory cap, with its raised terminals, is just ever so slightly too tall to fit the SL10's PS housing. Apparently, the original Mallory caps are 2.000" x 2.625" with raised terminals, which seems to be a nearly impossible size to find. There is a 22,000uF 50v Mallory of that size listed on that same page, which is all that I can find that's in that physical size, but I not sure about using a pair of those. Going from 13,800uF to 44,000 uF total PS capacitance is quite a jump.
 
MashBill said:



Thanks Forrest. I've seen those, but I was afraid they were too tall. Max inside height of chassis is 3.25", so I was worried. I went ahead and ordered a pair though to try out. I'll post a follow-up when I get them. If they are too tall, I will just build a new PSU with them.

Thanks again,
Bill


Forrestc said:


I just found that the above Mallory cap, with its raised terminals, is just ever so slightly too tall to fit the SL10's PS housing. Apparently, the original Mallory caps are 2.000" x 2.625" with raised terminals, which seems to be a nearly impossible size to find. There is a 22,000uF 50v Mallory of that size listed on that same page, which is all that I can find that's in that physical size, but I not sure about using a pair of those. Going from 13,800uF to 44,000 uF total PS capacitance is quite a jump.


Yes. My 10,000 uF / 75VDC caps came from Mouser today and they are too tall for the SL10 PS case....:bawling:

No loss though, I'll use them in something. I'm planning on building a new PS for this preamp anyway.

Thanks for the info on the new caps. With in-rush protection, they might work.

Bill
 
Yep, that one fits perfectly, and what's better, it didn't blow the bridge rectifier when I powered it up! Looks like this pair is going to be a keeper.

Do you think that there would be a benifit in using bypass caps with this pair of 15000uf Spragues? If so what R/C would you use?:)
 
Yes, the fit is perfect. The shorter can height combined with the shorter screw posts leaves more room than the original. :)

I don't know the rating of the bridge rectifier, but it looks beefy enough.

I've kind of changed my thinking regarding bypass caps. I'm not convinced that bypassing really improves anything. In fact I've seen data that shows that bypass caps can really do some goofy (bad) things.

With the SL10, which has onboard regulators in close proximity to the gain stages, I don't see the need to bypass at all.

Bill
 
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