Question about older C-J D capacitors...

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tzdvl
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Question about older C-J D capacitors...

Post by tzdvl »

Hello, all,

I own a Premier Three preamp, which was updated by conrad-johnson back in 1990 to include the 1986 "revised" stepped balance control, silver wiring and power supply capacitor upgrades. Other than those revisions the preamp is completely stock.


Image


I have a question about the film capacitors installed in the older "vintage" c-j components.


All of the capacitors in my preamp are film caps (except for three electrolytics in the heater supply and relay-timing circuits), and all are marked "C-J D" (for conrad-johnson design) except for three metalized polypropylene caps that replaced electrolytics in the original power supply.


Most of the C-J D caps are white with yellow ends, but seven are all-yellow.


I had always understood (from older reviews and product literature) that all of the caps in the signal path of the Premier Three were polystyrene film-and-foil type.


After some recent net-surfing of various audio forums I now wonder if there might be a difference between the older white C-J D caps and the yellow ones. It is possible that the yellow caps are actually polypropylene rather than polystyrene.


There are seven of the yellow film caps in my Premier Three. Five of these (marked 1uf/600V) are in the power supply, but two are actually in the signal path (one in each channel).


Image


These two caps (see the circled caps in the photo and schematic) are located at the input of the line stage, after the balance control. They are located on the smaller circuit board that mounts the mode switch and volume/balance controls, rather than on the main board. They are marked .5uf/100V and correspond to C32 in the schematic and parts list.


Does anyone know for sure if these two caps are polystyrene (perhaps "metalized" polystyrene rather than film-and-foil), or if they might be polypropylene?


Thanks for any info you might have about these "vintage" caps!


Ken
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Re: Question about older C-J D capacitors...

Post by Good Dog Jocko »

Polystyrene and polypropylene caps have a different smell when you fry them, so I prefer a really good single malt Scotch and some high energy music when I fry componets to ascertain their construction properties.

Mainly I just prefer the effect of the single malt Scotch, but my human is hung up on the sonic differences between capacitors. Maybe someday you humans will learn what is really important. But I have low expectations for most of you.
MLAS
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Re: Question about older C-J D capacitors...

Post by MLAS »

Apart from the "semi-philisophical' answer of the first poster on your question, did you ever solve the question about the kind of material used for the caps?
I believe CJ now prefers only Teflon caps.
whnay1
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Re: Question about older C-J D capacitors...

Post by whnay1 »

Those CJD caps were mostly polystyrene. The polystyrene's are not available anymore and all new deployments at CJ are using Teflons. There are some factory updates where they will upgrade the PR3 to teflons and vichay resistors. Contact them for more details...
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Re: Question about older C-J D capacitors...

Post by MLAS »

Hi Ken,

After almost a half year search I was able to locate a Premier Three pre-amp myself to accompany my Premier Five amps.
Tomorrow I will install it in my setup.

Did you already perform the upgrade from CJ with the Vishay resistors and their own CJD Teflon caps?
Do you know maybe the details about it because my communication with CJ HQ always is slow and incomplete.

Thanks in advance,

Robert
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Re: Question about older C-J D capacitors...

Post by whnay1 »

The ones that are white with the yellow ends are CJD Polystyrene caps and the yellow caps are polypropylene caps. Check with the factory about the teflon cap upgrade. It would be worth it but there be spce limitations since teflon caps are larger. Also replacing the resistors with Vichay helps.
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Re: Question about older C-J D capacitors...

Post by MLAS »

Okay thanks I'll try to check with CJ.
Can't find the Premier Three on their upgrade pages...
whnay1
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Re: Question about older C-J D capacitors...

Post by whnay1 »

it is likely because the teflon caps are much larger to fit.
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Re: Question about older C-J D capacitors...

Post by MLAS »

Yes think so too
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Re: Question about older C-J D capacitors...

Post by whnay1 »

They may be able to a partial upgrade where spaces allows for the teflons and then see if some of the polyprops can be upgraded too.

I had one of the first PR3's back in the 80's. It is still a sweetheart.....
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Re: Question about older C-J D capacitors...

Post by MLAS »

You sold it already?
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Re: Question about older C-J D capacitors...

Post by whnay1 »

quite a while aqgo. I am using a Prem 18LS and love it but may make a big move up to the ART-3 if I can find one.
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Re: Question about older C-J D capacitors...

Post by MLAS »

Okay you're on the move the current highend audio from CJ.

Do you have by any chance the accompenying Part List with your schematic of the Three B?
Love to have a highres from the schematic because my powersupply has been modified by a inexperience technician.
You're inside pictures too please.
They look like a brandnew pristine Three!

Thanks in advance,

Robert
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Re: Question about older C-J D capacitors...

Post by whnay1 »

I dont
MLAS
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Re: Question about older C-J D capacitors...

Post by MLAS »

Okay, thanks for your information so far.
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Re: Question about older C-J D capacitors...

Post by Stereo-One »

Hi whnay1,

Do you still have the 18LS? I was looking for a BAT VK-42SE but I have been told the 18LS has superior parts.
So I am looking for a 18LS. Are you selling your 18LS?

Thanks
whnay1
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Re: Question about older C-J D capacitors...

Post by whnay1 »

No, I sold it several weeks ago. I do have an ET3 (Brand New Factory Blem) List $3250 make offer.

There is an 18LS on eBay for $3000

Good luck,

Bill
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Re: Question about older C-J D capacitors...

Post by Jallen »

I have the CJ 18LS, have had the BAT VK42SE, and prefer the 18. The 42 is good, but not as neutral. The 42 was a bit soft and round. Both musical, just preferred the CJ neutrality with a hint of warmth. It bested my Presence Audio, a fantastic preamo, and my Calypso. Jallen
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Re: Question about older C-J D capacitors...

Post by whnay1 »

the 18LS is a superb product. Call CJ and send it in to have a Teflon cap upgrade. worth every penny.
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Re: Question about older C-J D capacitors...

Post by whnay1 »

I am an authorized CJ dealer. I just recently put in the Classic 120 SE and the new ET7 Tube preamp. I am getting the ART150 amplifier next week. These represent a major jump in the definition and tonal integrity CJ is known for. Try www.highnoteaudioshop.com
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