Changing coupling cap values / Using russian teflon caps

[EdStiles]

I know the ST-70 and Mark IV boards specify 0.047 coupling caps, but I would like to try the russian teflon and foils to see how they sound. Problem is the 0.047 mfd caps don't seem to be available, but 0.056 mfd caps are plentiful.

Any thoughts on this subsitution?

Also any feedback on the russian teflon caps? I see K72s, FT2s and FT3s, with 500 and 600 volt ratings. Anybody have experience on the sound or the "voltage safety factor" on these teflon caps? If I use a solid state diode, it could exceed a 500v rating for a few seconds until the tubes start to conduct... (I know about the size of these things)

Thoughts anyone??

Thanks,

Ed

P.S. Given the quantities sold on eBay, I may pre-Bay some teflons here if this feedback seems positive.

[Shannon Parks]

Hi Ed,

Subbing the .056uF is no problem without changes. I would also swag that the EL34 grid resistors can be resized to 100k (from 150k) and .1uF coupling caps be used. I intend to test this sometime - it's on my 'to do' list.

[EWBrown]

Those Russian .056 teflons s are pretty big, about the size of an AA cell. they're not going to easily fit on the board, perhaps hanging them from the bottom side of the board, with a little creative wire bending (the Russki caps have short soldering studs on each end). might work.

HTH

/ed B in NH