Hi Dept of Alchemy,
This tube rolling guide is amazing! I agree with almost everything there. Would be nice to add the Telefunken and Raytheon small mica EF95 tubes to the list. It is obvious that a huge amount of work and time went into this guide. Many thanks!
Looking forward to the power tube reviews which are not included yet.
The only thing left after this is to point out which combinations of power tubes and driver tubes work best.
(From a different post: I found it noteworthy that the 6N6P power tubes tame the overpowering treble of some tubes and make them very listenable.)
I am also questioning how important tube matching is, having heard that there are very large differences with a range of tolerance of up to 10% in the production lines. Another thing I do not understand is the statement in section 4.1 that power tubes failed after 100 hours due to mismatching. According to David of Little Dot the amplifiers are designed with totally separate circuits for right and left to the point that you can run different tubes simultaneously on each channel without causing any problems. Since I also had one of my OEM power tubes fail after five months (none of the driver tubes have failed during use yet), perhaps one has to conclude that the power tubes are more prone to failure than driver tubes.
In your conclusion you recommend the RCA black plate 5654 tubes for "solid all-around performance, great bass response and availability." I could not agree more. Right now I am enjoying the RCA 5654 tubes I have from Aug 1959 (rectangular slanted getters) and Novosibirsk 6N6P 1975 tubes. This combination is wonderful in my system with better bass than the Mullard M8100/EF95 tubes and has a lively, dynamic, toe-tapping inducing presentation. The sound as I am writing this is positively intoxicating. Powerful, tuneful bass, a beautiful, mellow mid range, exquisite highs, tremendous detail and a glorious 3D sound stage.
And for frugal people like me, I especially enjoy that all four tubes cost me $10.64 incl. shipping (even though I had to buy 9 RCAs and four 6N6Ps to get these prices).