Axis face silicon R3 silver mica cap

[Toney]

I have just started the R3 axis face and it calls for a 100pf silver mica capacitor across the base and collector of Q2. The function of this is said to smooth out and warm things up some.
I can buy silver mica locally but only for the rip off price of $3.99 ea.
Obviously stuff that. I'll mail order some soon. I'll have to wait...
In the mean time I'll try it with a ceramic.
I've never used silver mica before, can anyone comment on the advantages of the silver mica caps, especially as related to this circuit?

Thanks, Toney.

[Paul Perry (Frostwave)]

I suspect a npo ceramic cap would be just as good in this particular spot.
In fact for 100pf, you could make a 'gimmick' cap!! from a pair of wires twisted together. Or, what about a trimmer cap? 100pf is the range where you can get small ones of these.

[petemoore]

Well it does make A difference in mine at least, a ceramic was used, then replaced with a metal film, with the ceramic the high end clipping sounded 'coarse'.

[Paul Perry (Frostwave)]

Well fair enough, the ears are the final judge.
But if you use an air cored trimmer... I doubt anything could beat that!
And I suggest a cog cap, because at least the type of ceramic they use isn't the highly non-linear 'bypass' type..

[Toney]

Thanks guys,

Paul, do you know anywhere in Melb I can get those silver micas for a reasonable price? I live in Albert Park so inner city is best if possible..
Getting a bit over driving to Nunawading for bits (Tecs, Rockby etc)

RS has em, but $3.99 ea with a minimum purchase of five.

[formerMember1]

I am building the same pedal.  Parts should get here by this week.


I spoke to Phillip about the Axis face and the silver mica somtime back,  he said that the only 100pf cap that sounded good was the silver mica.  He said it made it smooth and warm,  I think he mentioned this in a thread on this forum, I'll try and find it for ya, :wink:

Good Luck my friend...

[petemoore]

I read that, tried that, and agree with that.
I had only the cercap to start off with, then tried the box film, surprized me, that is one position I feel as certain about for 'what type' cap making so much difference...ears Can be decieving, but it was a rather pronounced difference...I also believe I can hear a difference using all non ceramics in a circuit, but generally speaking can't tell one type cap from another in just one position.
 Point could be made that Ceramics are less closely toleranced...But...not in the FF Q2 B/C case I don't think...just sounds different.

[Toney]

OK, thanks for your input guys,

Have socketed the sucker so it's ceramic for now, but will put it through the taste test once the Silver Mica arrives.

[formerMember1]

yeah cool, post up your results when you try the silver mica cap :wink: