Calling All Cork Sniffers! (PF Content)

[Leo_Gnardo]

There's kind of a harshness in that amp. A kind of tone that's thin and papery that I feel may be due to the Xicons I have in there. Maybe I'm nuts?

We're all nuts, so join the crowd. Texas pecans mm now that's good!

Seriously now, have you looked at the output with a scope? Harsh, thin, papery, all describe what we hear when parasitic (ultrasonic) oscillations are present. Gotta scope it while driving speaker(s) as resistor loading doesn't often show this problem. I seriously doubt Xicon film caps are to blame.

Also doesn't hurt to have a cap meter in the workshop. Good investment, figure on $50-100. Some multimeters now include one.

[Markusv]

I agree with David Root
Polystyrene almost exclusively and they are available in 630 volt. Be gentle with soldering heat though
Mica on the PI and I just avoid disks for microphony fear

M

[Reeltarded]

Marshalls and Fenders can want that diffuse disk in there somewhere.

No?

Microphony is the wild horse between sterility and oh my god.

No?

[jelle]

yes

[briane]

Microphony is the wild horse between sterility and oh my god.

that and a tad of parasitic oscillation please.....I like my amp to have some 'natural wah-wah'

Its a balancing act - I make a large effort to mix and match - and not just use one brand everywhere. Or maybe I just like using up what I have on hand whenever its appropriate.

[Colossal]

I think that microphony in some ceramics, if used carefully, can add some real quality. They seem to give a little more focus and shimmer and maybe a hair more...hair (!). Kind of that telelphone vocal quality. I used a ceramic paralleled with a mica over the bright side of the mixing resistors in a current Plexi build.

[roberto]

My default in the pF range is polystyrene, 500V or 630V. Smoooth.

Something like this. Ceramic caps mainly into the amps (also in clean) and polystyrene in stompboxes.

[Markusv]

Thanks

Points taken and I will experiment carefully

M

[Blackburn]

I think that microphony in some ceramics, if used carefully, can add some real quality. They seem to give a little more focus and shimmer and maybe a hair more...hair (!). Kind of that telelphone vocal quality. I used a ceramic paralleled with a mica over the bright side of the mixing resistors in a current Plexi build.

I intend to try the ceramics in parallel too. I pulled a few in the .001uf and .002uf area from my old organ, along with many, many more .01s and heavy as hell dominoes.

And here they are..