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Ceramics or Silver Micas, or both?

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10/21/1999 2:32 PM

Ceramics or Silver Micas, or both?

I must confess that I got a bit confused when reading the thread on Silver Micas and ceramics. Why can’t things be simple – just Silver Micas or Ceramics!
From what I understand one has to use the “Ear method” to find out which cap sounds the best. My problem is that I wouldn’t know where to begin this test. Are there any particular “place” in the amp where the SM or ceramics (probably) would sound better (or worse) in a BF SR?

Bjorn

10/21/1999 2:36 PM
Mook	This is my take. I think the SMs work better in amps "designed" for humbuckers. And ceramics in amps "designed" for single coils. Some people report that Silver Micas are a tad bright and hi-fi"ish" - perhaps brittle? Mook

10/21/1999 4:00 PM
Jim S.	I like silver micas and use them a lot. I've replaced all the ceramics in my BF Fender amps and they don't sound harsh to me. I wonder if it's just that SM caps are relatively transparent and tend to reveal more of any harshness that may be occurring elsewhere in the circuit.

10/21/1999 8:32 PM

I replaced all of the treble caps, bright switch caps and the 500pf cap on the input to the reverb in my BF SR with silver mica. To me it sounds less grainy and clearer. I haven't noticed them being harsh or high endy, but there are so many variables in an amp it's hard to make any kind of blanket statement about what "sounds best". IMHO each amp is it's own entity and has to be tweeked to compliment it's own character and the fingers, ears and desires of the player.

Blues

10/22/1999 3:23 AM

to Blues, Jim, Mook and Bjorn:

    I just tried an interesting experiment with a boost circuit (to remain nameless!) that basically ran the full signal through a 330pF treble cap. One position of the switch used a mica cap and the other used a ceramic cap. With that setup you could really hear the difference between the two types of caps. With the mica cap there was a lot of the lower frequencies coming through which produced a fuller stronger sound. With the ceramic cap the low freqs were practically gone and the overall sound was a bit grainy.

    The problems with the mica caps mentioned by Gil in the earlier threads was that in the high-gain amp design he was working with, the mica caps allowed too much of the low freqs through which caused subsequent stages to "fart out". Switching over to ceramic caps was a "quick'n'dirty" way to filter out those low freqs that were causing the problems in the high gain stages, and was perhaps the best solution in that particular design (since more complicated ways to cut the bass might otherwise compromise the sound).

    While we all have our own personal tastes, I do think that most of us agree that a "farty bass" is not a desirable quality in the amps we build or modify. But in other instances where I have installed A/B switches to select between ceramic and mica caps, it is hard for me to decide which sound I like better... so I leave the switch in unless a later mod makes it so that I am always using just one cap or the other.

    Like an artist painting a picture, having both ceramic and mica caps in our "tonal pallet" gives us more colors to choose from... [end of soap box rant]

Thanks!

Steve Ahola

10/22/1999 6:06 AM

Nice test, Steve!

Just curious, though: did you measure the values of the two caps before doing the test? I have been fooled on many occasions by caps that say "330" on them, which means 33pF, not 330pF, which is marked "331" (they don't make a 331 pF cap, so this is a dead giveaway). It always pays to check these things on a cap meter, particularly when doing subjective tests, to make sure you are starting with the same value.

Randall Aiken

10/22/1999 7:37 AM

Steve, a minor clarification: with the high gain circuits we have all been playing, I complained that the silver micas were harsher, but not fartier. I actually didn't encounter fartiness with the "california" design. The micas were brighter and raspier in the top end, and the ceramics seems to wash out the buzz off the top end. I didn't really encounter any problems in the bottom end with either one.

Gil

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