5E3 Coupling caps - outside foil orientation

SunDevil

Gents,

I've just swapped the coupling caps in my 5E3 clone and the Red Jupiters I've installed are marked with the outside foil orientation.

In 3 cases, the caps are connected to the plate of the previous valve and so I've connected that end of the cap to the outside foil

In the 4th case, it's connected to the cathode and then on to the 6v6

So my question is whether I should connect the outside foil in the same orinetation as the other 3 or to the 6V6 end?

http://i1381.photobucket.com/albums/ah232/SunDevilarker/Easter 2017/5E3_zpsfelw3slh.jpg
http://i1381.photobucket.com/albums/ah232/SunDevilarker/Easter 2017/Jupirier Red caps_zpsqgcatu2l.jpg

exocet

Foil side goes to earth.....but to be honest I'm pretty sure we're entering into "cork sniffing" territory so I wouldn't worry.

SunDevil

Yeah - been reading up on the Aiken site and I suspect these are marked for the foil side for effect (in the same way as they are marked for 400v rating when they are in fact 600v)

Aiken talks about coupling caps foil being linked to the valve plate and to the cathode for bypass caps

In this instance as part of the PI, this cap is connected cathode of the PI valve to the plate for the 6V6

ICBM

exocet said:

Foil side goes to earth.....but to be honest I'm pretty sure we're entering into "cork sniffing" territory so I wouldn't worry.

No, foil side goes to the end with the lower impedance, if you're trying to minimise noise - which is not necessarily the ground end, in fact it's more commonly the HT end for coupling caps, as SunDevil has done.

The cathode to power valve one is the same - so the foil should be at the 12AX7 cathode end.

If it makes any difference at all, that is.

SunDevil

Thanks @ICBM - no noise at all at playing volumes, but I'll likely swap it due to OCD as much as anything else

jpfamps

The PI in a 5E3 is a concertina style.

This has very low output impedance when not driven into clipping, so the outside foil should be connected to the PI end for both the plate driven and cathode driven sides.

The outside foil is not always correctly labelled in my experience, but can be identified using a oscillascope.

exocet

There's a clip somewhere on YouTube that shows how to determine the "outside Foil" end.

SunDevil

Thanks Gents - I've no scope, but at playing volumes, it's not noisy, but I'll try it both ways around and see what difference it makes.

Whether it's subjective or not, I ..er subjectively can't say, but I'm enjoying the tone a lot better with the Jupiters than I was with the Mallorys