While I have not had a SFCD, I do own an SFP-1 signature. I have used the Siemens (70s vintage) gold pin and they have been the best I've tried--clear well defined and very open soundstage. I have not had the opportunity to use the Amperex, but given Jaguar's comments--I'd like to.
sfcd 1 best tubes
just purchased a used sfcd1 and am interested in changeing stock sovtek 6922 and recomendation i like a tube sound quiet background not that important thanx