Hey Newbee - one of my favorite sleeper preamps, the Cary Slp-50A used 6CG7's. I owned one for many years. I have a butt-load if you want to procure some good ones (even after that descriptor) to experiment with. I no longer have the Cary (great little pre for the money) so can only use them in my Modwright Transporter and there are better options there.
As far as 6n6 - a Googlization provides much input on the subject.
As far as 6n6 - a Googlization provides much input on the subject.