Ceramic vs Silver Mica

[jurgen]

I was skeptical but it makes a huge difference.

With mica treble and bright caps the high frequencies are audible
but sound like they're arriving behind the initial attack.

Silver mica bright caps sounded real nice in my twx clone but maybe
the high plate loads and and tightened cathodes of HAD'S design
make the pre-amp slew faster than the phase shift introduced by
these caps.

Apparently I have to learn it all the hard way -now to find some
low cap coax...

[Bob-I]

I was skeptical but it makes a huge difference.

With mica treble and bright caps the high frequencies are audible
but sound like they're arriving behind the initial attack.

Intersting way of describing it. I feel that I hear a "grain" to the ceramic caps that isn't present in the mica's.

[dogears]

I think Jurgen was referring to the ceramic and said mica by mistake.

I was skeptical but it makes a huge difference.

With mica treble and bright caps the high frequencies are audible
but sound like they're arriving behind the initial attack.

Intersting way of describing it. I feel that I hear a "grain" to the ceramic caps that isn't present in the mica's.

[briane]

Intersting way of describing it. I feel that I hear a "grain" to the ceramic caps that isn't present in the mica's.

exactly how I describe it....theres a certain granularity there, almost (in mathematical terms) like a discrete function versus a continuous one. The ceramic seems stepped, wheras the mica was smoother.

I have had some real problems with certain brands of ceramics early on in the signal path (bright switch/trebel cap/v1B grid), as they were letting a lot of humm and squal get into the amp. Funny, but swapping those caps for mica made that amp dead quiet.

Then again the ceramics sounded better (crisper, clearer), I just could not stand that much noise.

[jurgen]

To be clear: I much prefered ceramics in the D'lite

I think Jurgen was referring to the ceramic and said mica by mistake.

I was skeptical but it makes a huge difference.

With mica treble and bright caps the high frequencies are audible
but sound like they're arriving behind the initial attack.

Intersting way of describing it. I feel that I hear a "grain" to the ceramic caps that isn't present in the mica's.

[Bob-I]

Intersting way of describing it. I feel that I hear a "grain" to the ceramic caps that isn't present in the mica's.

exactly how I describe it....theres a certain granularity there, almost (in mathematical terms) like a discrete function versus a continuous one. The ceramic seems stepped, wheras the mica was smoother.

I have had some real problems with certain brands of ceramics early on in the signal path (bright switch/trebel cap/v1B grid), as they were letting a lot of humm and squal get into the amp. Funny, but swapping those caps for mica made that amp dead quiet.

Then again the ceramics sounded better (crisper, clearer), I just could not stand that much noise.

I've had quite a few ceramics that have gone directly into the garbage, sometimes just from measuring. I just had a 39pF measure out at almost 60pF, garbage. The next one out of the bag measured 41pF and sounds great. You can't be afraid to trash a few $.05 components in the quest for tone.

[skyboltone]

I've had quite a few ceramics that have gone directly into the garbage, sometimes just from measuring. I just had a 39pF measure out at almost 60pF, garbage. The next one out of the bag measured 41pF and sounds great. You can't be afraid to trash a few $.05 components in the quest for tone.

I've got gobs of VD ceramics that all measure 10%-20% low. I called the manufacturer of the meeter and he explained how it's just not possible (the way cap meters work) for it to be the meter. I dunno. It's kinda aggrivating. I got Xicons that are all over the place.

[greiswig]

Man, how are you guys measuring such little caps? I've got a Fluke, but it won't go that low!

FYI, I tried A/B'ing a pair of 200pf Polystyrene film caps in series against a 120pf value ceramic cap in the bright switch, and I preferred the ceramic. It also sounded like the polystyrene caps had *more* capacitance, that the knee was lower. Interesting...

[Bob-I]

Man, how are you guys measuring such little caps? I've got a Fluke, but it won't go that low!

FYI, I tried A/B'ing a pair of 200pf Polystyrene film caps in series against a 120pf value ceramic cap in the bright switch, and I preferred the ceramic. It also sounded like the polystyrene caps had *more* capacitance, that the knee was lower. Interesting...

I use a cheepy meter I got from ebay for about $50. It's so sensitive that if I put the test leads too close together I'll read 1-2pF more.

Don't forget about the other factors on caps, like ESR, Effective Series Resistance. That can change the way the cap acts in the ckt. It's also a big factor with you use 2 caps in parallel to increase the value, the ESR lowers.

[gregarious]

Don't forget about the other factors on caps, like ESR, Effective Series Resistance. That can change the way the cap acts in the ckt. It's also a big factor with you use 2 caps in parallel to increase the value, the ESR lowers.

Bob does this mean you're an advocate of using caps in parallel to obtain the required value?

What about resisters - I have a quantity of 2 watt 120k CC's that measure 112k & 108 - the 112k which I combine with 1meg 1 watt carbon film to get 100k & 108k with 330k to get 82k - seems to work ok.

[dave g]

I tried some micas in a D-style amp as well and have to agree that they don't fit right. That being said, I love them in Marshall style amps...

[greiswig]

Don't forget about the other factors on caps, like ESR, Effective Series Resistance. That can change the way the cap acts in the ckt. It's also a big factor with you use 2 caps in parallel to increase the value, the ESR lowers.

Interesting, but I don't know what ESR means at this point in the signal. I'm going to guess, based on the terminology:

If you increase the ESR, the acoustic effect will be similar to adding a resistor in series with the cap value. Is that right?

[Bob-I]

Don't forget about the other factors on caps, like ESR, Effective Series Resistance. That can change the way the cap acts in the ckt. It's also a big factor with you use 2 caps in parallel to increase the value, the ESR lowers.

Interesting, but I don't know what ESR means at this point in the signal. I'm going to guess, based on the terminology:

If you increase the ESR, the acoustic effect will be similar to adding a resistor in series with the cap value. Is that right?

I wish I knew. All I know is that parallel caps don't sound the same as a single cap of the same measured value.

[greiswig]

Don't forget about the other factors on caps, like ESR, Effective Series Resistance. That can change the way the cap acts in the ckt. It's also a big factor with you use 2 caps in parallel to increase the value, the ESR lowers.

Interesting, but I don't know what ESR means at this point in the signal. I'm going to guess, based on the terminology:

If you increase the ESR, the acoustic effect will be similar to adding a resistor in series with the cap value. Is that right?

I wish I knew. All I know is that parallel caps don't sound the same as a single cap of the same measured value.

Well, I guess I'd expect that, too, based on the same theory: parallel caps (or the same value cap with a lower ESR) should effectively sound like a larger value cap. Hmmm....

[briane]

I wish I knew. All I know is that parallel caps don't sound the same as a single cap of the same measured value. Embarassed

Absolutely! I take this into account when doing a build (in some meager way).

I have some theories about this, as its an additive waveform (sine if you like) rather than the full waveform. As an additive waveform rather than an essential one, it behaves differently....without getting into to much red tape hypothesis's here.

Try putting a 100 pf cap across the cr, one with a 25 uf cap or so standard. The change tonally is amazing, but the capacitance has changed by only a meager portion of a percent. This proves the additive theory of not being the same as the essential, as in theory you should not be able to hear the difference, but I am still learning about this.