Dennis Had Inspire Amps

[Isaacc7]

Originally Posted by Bombadil

Hard to say which 6SN7 variant will be best to your ears. People have different preferences.

I've tested out about 25 different brands and years. My two favorites are 1960s Westinghouse 6SN7GTB tall copper rod and a 1940s Raytheon VT-231. Close behind are some 50s and 60s Sylvania, but I haven't had a chance to listen to the famous Sylvania Bad Boy 6SN7GT 3-hole black plate, copper grid. These were only made for 18 months in 1951-1953. Many other Sylvanias from the 1940s and later 50s are advertised as Bad Boys but are not the real McCoys.

I do have a new Psvane CV181-T MkII, which has received rave reviews and liked by many in the online forums. I found it to be good, but not great. I like a big open soundstage with good detail. This tube produced a smooth, pleasant sound while a bit softer on highs and a slightly diminished soundstage. I understand why many like it.

As to the VT-231 tubes, these are "military" in name only. The military wanted their common tubes to adhere to their inventory numbering system. So companies simply started labeling their standard production 6SN7 tubes as VT-231. No changes to the tube itself. However if it is labeled as a VT-231 then you are assured that it is an old tube made in the 1940s.

Years later the military started demanding strict low noise standards and long life and tubes which passed these tests were designed as "JAN" or "USN" military spec tubes. Some believe, and many dealers promote, the earlier VT type tubes as being similar and having passed more rigid testing, but they weren't.

I have enjoyed using short bottle Sylvania 6sn7 tubes in other amps. Once I dig mine out of storage I will try them in my KT88 Firebottle. Have not heard the "bad boy" versions but I bought a few pairs of the 12v version for my Supratek preamp I'll get in 3 months or so. The reviews of those tubes have been great, hope they live up to their reputation.