Tuesday, November 11, 2008

Soviet Madness : the 6N6P dual triode

The 6N6P is a large 9A base dual triode - under the cyrillic alphabet it is called the 6H6. The 6N6P is a wide band power amplifier and has nothing to do with the American designated 6N6 which is an octal power tube from the days of yore. The Russian 6N6P is a modern built tough tube obviously built for military specifications with the ability to handle high-g loads.

The 6N6P is starting to get used by manufacturers (K&K and Lamm comes to mind). It is also one of the last cheap tube values available on Ebay - going rate is $4 to $6 per tube. It looks quite like the 6H30, though the 6N6P has different characteristics (higher mu and higher rp). Though the 6N6P has the same pinout of the 6922/6CG7 it is a much different beast - be warned since it uses more than double the filament current of the 6922 and an extra .15A over the 6CG7. It is actually in operation closer to the 5687 family.

I bought a pair of these from Ebay and they look extremely well made with a tall bottle and massive getter area. I plugged them into a White Cathode Follower circuit based around the 6922 tube. Not an ideal circuit, but I was quite surprised on how good they sounded. My curiosity got the better of me so I took my existing 5687 linestage and re-wired the filament leads to accept the 6N6P.

Initial impressions it has quite a bit of the 5687 character, but it has a certain spaciousness and speed the 5687 (or at least the Tungsol) can lack. Back to front depth is very good, which really helps with the sense of 'being there'. The 6N6P is very neutral top-to-bottom and appears to be a good match with the rest of my system. This is a surprisingly refined tube and in the end I preferred it over my vintage Tungsol 5687s.

An excellent option for building headphone amplifiers, linestages, and for driving output tubes.