UPW caps are low leakage by nature, and inherently low noise.(actually low ESR types) and will perform just dandy in those locations. In the signal path, anything 4.7uf and under I replace with film. In the power path, UPW.
Is that because of the history of the old tantalum caps?
I've heard that said about film caps. So that's what I've been doing. In another post I read through someone said you should install UKL's where the yellow Chemi-Con's are. But if UPW's are suitable that's good because I already have them here.
Understood. I did notice the service manual didn't specify low leakage caps where yellow ones are used. If it's not helping anything I'm sticking with the UPW's I already bought. I did notice in locations on the tone board where they have 4.7uf 25v orange caps the service manual also doesn't specify low leakage caps for those locations. Didn't Pioneer usually use the orange caps in locations where the service manual called for CEANL caps?
Yes, UKL are low leakage. But also with newer processes and materials, UPW leakage spec is up to snuff, as good as 50 yr old LL of the day.
The orange Nichicon caps with the shiny black seal are "audio" caps of the day and were Low Leakage/Low noise. Modern quality caps perform just as good. Using film in their place is best since it eliminates any effects of electrolytic such as ESR and noise, allowing the AC signal to pass cleanly. It is also best to determine which lead is the "outside foil side" lead to use in the negative spot, but that's splitting hairs in SS gear. Having the signal on the outside foil side CAN lead to picking up noise. But in practice it has proven to be negligible for the most part. Although some die-hards are meticulous about it. Tube gear is a lot more susceptible to noise than Solid State so it does pay in tube gear. Mr. Carlson's Lab on You Tube had a video about it about a year or so ago, and how to find which side is the outside foil lead using an oscilloscope.
Well Tantalum caps will explode when they fail, and the resulting fireball "ain't pretty".. Not to mention the "oooh, that smell"
. And it seems the "audio quality" isn't all that great either compared to a modern electrolytic. A Tantalum IS an electrolytic by nature, it's just a "solid" type. Modern Tantalums have been reported by some to sound "just fine" though. But we all know "sounds fine" is very subjective. Back in the day, they were used mostly in tight places for their size. And the end result was "in spec" for THD/Noise for the price point.
That's interesting. I always thought it didn't make a difference with film caps due to them being bipolar. FWIW I did end up using Wimas in place of the orange 4.7uf 25v caps. Although I didn't install them in any specific orientation.
Wow!Well Tantalum caps will explode when they fail, and the resulting fireball "ain't pretty".. Not to mention the "oooh, that smell"
This is one result of a Tantalum failure. It was a 6.8uf 25v Tant running on regulated 12vDC and it still exploded with a vengeance. This was in a Telescope hand controller. That flat keypad cable is irreplaceable. The explosions on the main board in the base of the scope is just as ugly, and it takes out the main ROM chip that is also irreplaceable. I see a Tant, I "shoot on sight" without hesitation. Space is limited so I use a modern 50v Tant when replacing them. A small electrolytic would dry out too fast, and a film is too big to fit.
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Most of the time it's a non issue. Only on the very rare occasion if a component carrying signal that is up against the cap will there be any "noticeable" noise. Even then it will be so subtle it's hardly an issue and might be "seen" on a scope, but not "heard" with the ear.. I personally have had no issues whatsoever with orienting film caps in SS gear. As far as replacing non-polar electrolytic caps, it's easy to see the foil side lead, it's the "short" one just as the negative lead is in a polarized electrolytic. The modern manufacturing process is the same for either one.
Up to this point I haven't used any nonpolar electrolytic caps in my stereos. Now that I'm slowly getting a better understanding of what I'm doing I want to start experimenting with different caps. I believe this information will be useful going forward. Thank you for explaining it.
This post just brought back a long forgotten memory of a heated debate with an old girlfriend about the toilet paper roll.
You gotta watch it, there are Bi-Polar (also known as non-polar) caps in a LOT of gear in specific places.
