• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Which BG cap best suited for cathode bypass?

I am about to order Black Gate caps for my pre-amp project and I am little bit confused - one source claims that FK serie is best for cathode bypass and other source claims that non-polar NX serie is best!

Could you please give me some ideas which type to order, because I haven't listen to any FK and NX caps till now. I really don't know how they would behave there. Thank you in advance.
"The latest news is that Takeda/Jelmax have announced that for the time being Rubycon will continue to produce the full range of Black Gate capacitors, probably due to the enormous rush of orders they received in the run-up to ceasing production. This is good news indeed, even for us who have invested in years of stock at considerable cost.
Peter Qvortrup
10th April 2005"

Seems they are available after all.
Myth or fact: "BG N caps must be used constantly to sound good"?

I read on the net that BG N-type caps (after initial forming) continue to sound good only if they are used constantly, and that otherwise they will have to be "re-formed" again and again (e.g. after you have not used the amp for 3 weeks).

Is this myth or fact? If this is true, are there alternative cap choices that are not so "touchy"?

Best wishes
BG FK vs Nx

I've tried both BG Nx and FK and the Nx sounds more refined in my 2A3 amps. I think the bipolar and symmetrical construction of the Nx helps here.

Both types are definitely better sounding than the Standard BG's. I have ordered a supposedly last large batch of BG's in the Netherlands which should arrive this week (types: Nx, Wkz, NH and VK).

I am glad to get rid of all those large oilcans in the powersupply of my tube amps!