PV11 cap replacement, original or upgrade?

The PV-1 to now...
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foothillphile
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PV11 cap replacement, original or upgrade?

Post by foothillphile »

Hi, I have owned a PV11 from new. Several years back I got a poping sound in one channel when on phono.

I realized this to be a leaking coupling cap. Being rural and pre computer, I opped for a radio shack replacement

cap to make do. Now it's time to replace that (noisy cap) and it's complement cap in the other channel. Question

is, do I contact CJ and see if I can get an original replacement cap from them, or replace with on-line available caps,

which brings up what type might be an upgrade?? The value is .15MFD 200VDC, it's a CJ cap even dated 92-08.

Should I look for teflon or poly or?? What's hot today for ultra low noise in a phono stage? ?

Sugestions? P.S. why so hard to find a PV11 schematic on line? I'm suspicious of that 200V value.

Vince
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camusmuse
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Re: PV11 cap replacement, original or upgrade?

Post by camusmuse »

I just replaced a little 50v 22uf cap in my PV1 PS, definitely upgrade an upgrade to what was there. Though the 11 and the 1 are literally years apart, CJ is still a business and will use the "best" least expensive parts they can get away with(or have available to them in economy of scale at the time). The voltage itself may not matter all that much, depending on where it is at in the circuit. Since it sounds like its in the phono circuit in your post, then definitely go with what you can afford, though; .15mfd @200v shouldnt be that expensive, I say buy a few different ones and see if you can tell the difference....
unclestu52
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Re: PV11 cap replacement, original or upgrade?

Post by unclestu52 »

If you want an original CJ cap I have some pulls tested good. Free if you email me
Good Dog Jocko
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Re: PV11 cap replacement, original or upgrade?

Post by Good Dog Jocko »

Be sure to replace in BOTH channels with the same capacitor, to prevent any distortions between the two channels.

At the age of your preamp, you might want to consider rebuilding it and preventing a cascade of irritating problems.

I disagree with the part about C-J using the cheapest parts available. C-J is usually much better in parts quality than others at their price point. However, at the price the PV-11 sold for, it was impossible to supply ABSOLUTE state-of-the-art components. C-J has usually supplied state-of-the-price components. That is all you can ever expect.
jeffreybehr
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Re: PV11 cap replacement, original or upgrade?

Post by jeffreybehr »

foot, my PV11 schematic indicates that a 0.15/200 is the bypass cap on the larger 2/250 output-coupling cap. Most probably, the 2/250 is a 'propylene and the .15 is a 'styrene. (The earlier intersection coupler in the phono stage is another 0.15, but that one is rated at 400VDC.) Keeping things on about the same quality level, I'd use a MultiCap RTX 'styrene, either a 0.1/200 or the 0.15/600, depending on size. The RTX is an excellent cap, what I and lots others consider to be a 5-star-quality cap, and at the prices of premium-quality caps nowadays, it's a bargain. (The value of the bypass cap is NOT critical.)

http://www.soniccraft.com/multicap_rtx.htm

There's not a PV11 schematic among those on this site? I think I sent one.
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William Bruce Cameron: "...not everything that can be counted counts, and not everything that counts can be counted."
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Re: PV11 cap replacement, original or upgrade?

Post by jeffreybehr »

A few more thoughts on the PV11.
1. I see that c-j did not use a line-stage input-coupling cap, as they did in the PV5. That will improve overall transparency a tad compared with having a coupling cap in that position.
2. This preamp uses cathode followers in both sections to reduce output impedance, a very common thing a few years ago. C-j now uses MOSFETs wired as emitter followers (if that's the correct engineering term) to do that.
3. The line stage has only one stage of gain and hence reverses signal polarity. You knew that, yes?
4. This uses only 'propylene with 'styrene bypasses (that is, NO 'lytics) in the HV powersupply; that's really good.
5. The unit looks as if it'd be fairly easy to improve its sonic quality by replacing coupling and powersupply-output caps. If you're interested in doing any of that, e-mail me at jeffreybehr(at)cox(dot)net and I'll give you some recommendations. Oh ya...do remember that free advice is often worth exactly what you pay for it. In this case, I hope mine will be worth a little more than that.
:)
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William Bruce Cameron: "...not everything that can be counted counts, and not everything that counts can be counted."
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Re: PV11 cap replacement, original or upgrade?

Post by admin »

jeffreybehr wrote:

There's not a PV11 schematic among those on this site? I think I sent one.
Unfortunately, the PV11 is not in our database. If anybody does have a copy and sends it to me, I will of course update the CJO database to include it in our files.
-admin
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Main stereo: ART Amplifier and ET7s2. 2nd stereo: PV-14L and MV-55. Previously Owned: PF2 preamp, Evolution 2000 Amp, PV-12AL preamp, D/A-2b Vacuum-Tube Digital Processor.
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