I don't know, I haven't tried other types in the RIAA circuit. Worst - soundwise, or measured?
Polypropylene mostly (MPP, MKP, CBB). Polycarbonate if I'm lucky (MKC). Not Polyester (MKT).
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Hi kodabmx,
I use those as well, but my choice is determined by value. There isn't much overlap between polystyrene and polypropylene.
~ So far I like Ultralinear the best. Triode mode runs too hot for little power.
I use those as well, but my choice is determined by value. There isn't much overlap between polystyrene and polypropylene.
~ So far I like Ultralinear the best. Triode mode runs too hot for little power.
Not the ESR, but dielectric absorption, which is particular loss mechanism having a very small global impact on ESR, Q, tan delta or whatever you name it, but capable of creating very specific problems, for example equalization inaccuracies, smearing of signals due to settling time and lagging effects.
In a RIAA circuit, it will degrade the equalization accuracy because the LF value of the cap is larger than, say its 1kHz one.
If you use nominal values, the LF's will be overcorrected.
The circuit might be designed around specific mica caps, taking into account their imperfection, but even so it cannot be perfect because the capacitance is not pure.
PP caps are accessible, and show very little dielectric absorption.
Keep mica for HF applications
I just find PS is hard to find in high voltages, and it's sensitive to heat - both of which are things encountered in any of my amps (for instance, I use 1kV caps to couple the driver to the output because before the tubes are hot there's an 800V differential).
Hi kodabmx,
Yes, 630 VDC is normal. Higher than that - don't know. The cost on all parts goes through the roof above 500 VDC. My designs stay below this level because I feel going higher is a waste of money. That's just my opinion. Even wire gets a bit pricey above 600 VDC ratings.
-Chris
Yes, 630 VDC is normal. Higher than that - don't know. The cost on all parts goes through the roof above 500 VDC. My designs stay below this level because I feel going higher is a waste of money. That's just my opinion. Even wire gets a bit pricey above 600 VDC ratings.
-Chris
Looks tempting to build! I dont know what one to go for now lol I was told by a mate that the other one was a very good design.
Yeah that makes sense, its probably better just to buy a bunch of the cheaper film types and test them to measure their values and select the best to match.
Interesting to see that, i had done a search for 0.03 and found nothing.
I believe its a bit of both, all i know was the guide said it preferred polystryene, film second and stay away from mica or ceramic.
the quote below seems to shed more light on this.
Some schematics do specify mica after looking at a few.
OK, interesting to hear, the schematic shoog posted appears to be a well regarded design and specifys mica caps.