What I was asking about is why not use all bipolar capacitors since they all interact with the audio signal? Is there any reason to not use all bipolar? Just like the input caps on the phono board, originals were polar and I installed bipolar. So why not to all of the caps in the preamp that deal with the audio path. The largest cap in there is a 4.7uF.
I’m sorry, but what are you saying exactly? Kind of went over my head. Let’s say there were larger transients at power on and power off, how would a polar capacitor deal with that better than a nonpolar? You have a polar capacitor rated for 35 V and it sees a transient of 40 V which it can handle for so many seconds, wouldn’t it be the same for a 35 V rated?
Dan
I don't know all the possible reasons. But one reason is often the cost. Another is the very small capacities that are available as bipolar, which are rare or even unfeasible as polar. Since the vast majority of devices are not developed by ear, and certainly not back then, sound, tonal tuning, is not the reason;-)
Transient voltages across a coupling capacitor can be as large as the rail voltage.
In some circuits the transient voltages can be of reverse polarity compared to the steady state voltage,
which would damage a polar electrolytic capacitor.
a capacitor, any capacitor will have its voltage specs based on its insulation properties...as long as the insulation can handle the voltage without damage, then everything is fine, transients should not cause any capacitor to dissipate power, that would have to be catastrophic...
So in that case it would actually be better to use a nonpolar capacitor in those spots which is what I want to do. Since they used polar I’m guessing they the transients are bad enough to damage the caps since they all still work in a sense, but regardless, the UES I want to place there are a bit higher voltage.
I’m getting a little confused here, are you saying it’s a bad idea to put the UES nonpolars in on the preamp/tone board?
Dan
I've used the UES bipolars for coupling with good results. There's no reason you can't use them instead of a polar type.
You have to consider the normal circuit operation, transients from turn on/off, and possible failure modes.
If a transistor shorts, etc, you don't want the coupling electrolytics to be damaged from excessive or reversed DC voltage.
You have to consider the normal circuit operation, transients from turn on/off, and possible failure modes.
If a transistor shorts, etc, you don't want the coupling electrolytics to be damaged from excessive or reversed DC voltage.
Then no lytics in signal path - throughout the device (except some in feedback chains and tone control - depending on the circuit solution).
If you keep whatever lytics in signal path then it is just not worth any effort.
We all have our own preferences - the context is 5000 LPs which is not just trivial listening...
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It's possible that enlarging the coupling caps might lower the phono stage's low frequency cutoff to below what is needed, inviting excessive woofer flap caused by warped disks. It depends upon the impedance the stage is working into. I'd be careful about enlarging the caps; they might cause trouble with no real sonic improvement.
Like I wrote, we all have our preferences.
Once and old cap from signal path is soldered out I personally see no sense in soldering in another lytic (unless the target is to preserve original look as much as possible) - polar or bipolar, does not make any difference.