Paper oil caps in trem circuit?

[azatplayer]

I just finished my brown vibrolux, sensational amp! Very sweeet cleans and an almost dumbleish gain, kinda..
In fact the gain thats there kinda shocked me, really usable, in fact you have all he pretty non-icepick cleans on hand and then wound on has some seriously cool saturated tones, i love it!
Just a question on the trem circuit. Its a bias wiggler and works quite nicely, THO not as impacting as i thought it was gonna be. Nowhere as swampy actually as my swart can get.
The only caps i had on hand at the time were paper/oil. The soviet K40y-9's.
I LOVE these caps in fender builds. I have them in a 5E3, very nice tones.
Ive got them thruout the amp, i actually started out with poly caps as the board is compact and the pio's i have are 630V and big! But ended up with the pios in there after a bit of tweakage.
Im wondering if the PIO's are maybe not the right cap for a trem circuit.
Generally you see big ceramics in the old amps, and ive seen polys in newer versions. I wonder if the paper caps maybe release too fast, and dont get as saturated as the ceramics or polys?
Really reaching here. Anyways as usual i ask some advice, as i heat up the soldering iron... i have some polys now in my drawer, so will try them out.
I had set the bias supply up with a marshall style setup, and thought maybe it was responsible, but i just tried the stock type and made no diff.
Anyone used paper and felt they were wrong for trem?

[martin manning]

I don't think the type of caps used in the feedback loop will make any difference as long as you can get the frequency range; it's the magnitude of the bias shift that's important.

The notes on Fender's Custom Shop Vibrolux reverb schematic say that with intensity and speed controls at 100%, the voltage at the junction of the bias feed resistors should be 55V pk-pk sine at 8Hz, with the nominal bias voltage being -45V. I'd look for that kind of proportion.

[FYL]

Generally you see big ceramics in the old amps, and ive seen polys in newer versions.

You need highly resonant caps in the oscillator circuit, that's why basic ceramic discs are really fine there...

[azatplayer]

Well just tried some poly caps, and there is a subtle difference. I just remembered i ordered some ceramics for a build ages ago, just dug them out of my cupboard. Will see what they sound like next.
I had a think about the bias setting. The schem calls for -36V supply to the intensity pot. Ive read that running these amps a little cooler is the go, so i had set it up with an adjustable bias and had the tubes at about 52ma each with plates of 365, bang on spec with that voltage.
That gave me around 63% dissipation. I figured that was cool enough.
But decided to try leaving the supply at -36V. Well that gave me 48ma per tube at 375V, which is 60%.
That ever so slight drop, made all the difference in the world.
Gave the intensity much greater depth.
So i went lower again, but ended back up where i was!
There is obviously a small sweetspot where the oscillator has maximum affect.
Learned something new