|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
69.87.203.163
In Reply to: Replacing CJ Polystyrene caps to Mundorf Silver in Oil on CJ amps posted by Jason Michael on April 24, 2007 at 23:20:39:
Polystyrene caps (once common, now rare) are the best available for audio after Teflon. CJs are very high quality too.
Oil caps are fasionable and trendy but grossly overrated.
I think you will ruin the sonics CJ tried so hard to perfect.
And your resale value will go down the drain, unless you do not disclose the sin.
What are you trying to achieve? Just curious.
Follow Ups:
Yes, the CJ polystyrene caps are Conrad Johnson's propriety caps and considered high quality, but i think the newer technology caps are equal or may be better that these caps. I've read that the polystyrenes poor heat resistance and they can be damaged by soldering ( http://my.execpc.com/~endlr/film.html ).. hmmm inside the amp is quite hot.:)As for the resale ... i think the Premier 11a is a keeper and don't intend to replace ( as fo now ). Further more, the mod is reversible so if i plan to sell it in the future, i can just solder back the original styrene caps.
" Polystyrene:
Polystyrene (PS), (the Europeans often call it "styroflex" or "styrol") has long been the material of choice for critical analog circuits. Low leakage, low dielectric absorption and a shallow, flat temperature curve makes these capacitors suitable for timing circuits, filters, integrators, and sample-and-hold circuits. Moisture absorption is very low. Size, cost, availability, and temperature range limitations make polystyrene unsuitable for most other applications. Heat resistance is limited to about 85C, so forget surface mount. They can be damaged by soldering and by chlorinated board cleaning solvents. I don´t believe I have seen them in metallized film, only in film-foil.Because of the poor heat resistance, polystyrene has largely been replaced by polypropylene and C0G ceramics, and the capacitor-grade film is no longer being made. There is several year´s supply still available, and they are still being sold, but be careful using them in new applications. Some manufacturers have noted that polystyrene caps are "not for new designs". One company, ITW Paktron, makes polypropylene capacitors with a guaranteed temperature drift similar to (if not quite as good as) polystyrene. PS's other electrical properties are mostly very similar to PP.
Whether polystyrene capacitors will really go away any time soon is not certain. I have been warned of polystyrene´s demise "in a few years" for over a decade now, and yet it is still available. There almost seems to be vast supplys of the film stashed away in manufacturers back rooms. It may also be that declining usage will extend available stocks for many years to come. I imagine that many of polystyrene´s traditional applications are fading away as newer technologies take over. "
Polystyrene production came to a screeching halt because it's production had hazardous wastes, including dioxin. This brought most EU production to a halt. Recently, however, I have heard rumors of a factory in China gearing up for polystyrene production.Polystyrene is supposed to have the shortest 'memory' of any dielectric, IIRC. Even better than teflon, which was the original reason CJ elected to build their custom caps from 'styrene. I do recall there were many problems when polystyrene product halted and CJ was forced to used alternate purveyors for their caps. Not all were as good as the original vendor (Southern/F-Dyne, IIRC).
Hi.Obviously swapping caps seems to be the easiest way to change the sound of an amp, for better or worse (who knows). But please don't make it a habit.
Those costly exotic cap vendors should chime in here to thank for interest-free financing from those frequent cap buyers.
I have done tons of sonic build/upgrades, from phonostages to power amps, & loudspeaker systems, changing caps to me is a minor & very passive way of sound upgrade, if any at all.
But it would be a good way to "mush-out" the sound if you want it to sound slow and syrupy.
| ||||||||||||
|
This post is made possible by the generous support of people like you and our sponsors: