I have been working on a board for use in a record CUTTING chain that is going to be using C0G (Which has rightly taken much of the polystyrene market). These are NOT your high K ceramics (Which are unsuitable for use in filters), and are in fact excellent.
It is interesting to note that the classic German recording lathes used at best 5% components in their equalisers back in the day (Also, they generally had an extra pole or two up in the low ultrasonic to deal with stopping the inverse RIAA curve rising at 20dB/Decade into the AM radio band)...
I discovered the other day that COG extends out to 1uF these days (at a price, but still pretty amazing, I remember when a couple of hundred pF was the upper limit).
One hint if doing the low K ceramic thing (And there is little reason not to), above about 0805 in size, get the soft termination ones, more likely to survive less then ideal soldering practises without cracking.
Regards, Dan.
It is interesting to note that the classic German recording lathes used at best 5% components in their equalisers back in the day (Also, they generally had an extra pole or two up in the low ultrasonic to deal with stopping the inverse RIAA curve rising at 20dB/Decade into the AM radio band)...
I discovered the other day that COG extends out to 1uF these days (at a price, but still pretty amazing, I remember when a couple of hundred pF was the upper limit).
One hint if doing the low K ceramic thing (And there is little reason not to), above about 0805 in size, get the soft termination ones, more likely to survive less then ideal soldering practises without cracking.
Regards, Dan.
HifiCollective in the UK carries LCR and some generic types as well.
Polystyrene Capacitors | Hifi Collective
Thankyou, now I remember, and stand corrected!
hmmm, but if eventually the result statistically tends towards the nominal, then the distribution is not really random.....???
in a truly random scenario the result should still be within the 5% tolerance..
XD
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Doesn't work that way, cancels just like noise for the reason component variation is a kind of noise.
However there is a caveat, which is you have to assume the 5% parts are unbiased, ie about 50% are over-value and about 50% are under-value.
If you can assume parts are chosen by binning after measurement, this is a valid assumption.
However that's not always how components are made. The production line can have continual feedback to keep the output components close to the desired value. Typically this means 5% components have much closer grouping than the 5% suggests, but perhaps with a gap in the middle where the 1% components are selected out.
It makes sense to try to make all 1%, and the rejects go to the 2% or 5% bin. If the demand for 5% is high, then excess 1% components are demoted to the 5% line (noone's going to complain!).
Basically you can't quite assume the 1/(sqrt(N)) improvement in precision when using multiple devices, but if you SOT then you'll get much better than that anyway.
Sorry to resurrect this old thread, but has anyone tried polyphenylene sulfide (PPS) capacitors in their RIAA? OK dielectric but great mechanical and thermal properties. Considering ordering some and given them a try...
PPS is the way if doing SMT Film, gets you a bit more thermal margin in the reflow oven, never done an RIAA with them however, but it is contrary to some opinion, not a particularly difficult application and I would expect PPS to do fine.
Yup, work for me. They are close to PP in performance I believe. You can get high temperature insulated mounting hardware made from PPS too I found out. Should work happily upto 100C from what I've found out. Can get stereo RIAA preamp and 4 pole rumble filter on quite a small PCB this way:
Do you think most of the advantage/value of PPS is lost when not using surface mount components? Thanks for the reply!
Huh? Its PPS, whatever form its in, its still the same dielectric. For SMT you require the capacitor to not melt when the PCB if reflowed, so you cannot use PP or PS.
Sorry, I meant that if the main benefit of PPS was in making smaller devices and in its high temp tolerance, there might not be much benefit to using through-hole PPS caps over PP in an existing design. I was mostly wondering if there was any sonic benefit of PPS over caps that use other dielectric materials.
What do you imagine a "sonic benefit" is? PPS is better than mylar, this is well documented. Checkout Cyril Batemans articles for instance
https://linearaudio.nl/cyril-batemans-capacitor-sound-articles
https://linearaudio.nl/cyril-batemans-capacitor-sound-articles