Finding myself in violent agreement with the recent collective forum concensus of impressions for rectifier and signal tubes in the MWTP.
While they vary significantly between brand, date and construction, I never met a 6CG7 that I didn't like. They all seem to have a nice presentation of high freqs along with a nice midpoint for gain. 6NxP's just begin to sound shrill after a while and, no matter how hard I try to love them, tend to enjoy brief respites in my unit. The 6H30-DR's impart and elegant sound but do so with the expense of several dB of gain making comparison difficult.
It is within rectifier land that things get most interesting. On one end of the spectrum, the MB GZ34 reigns in the areas of image and soundstage... on the other, the better 5U4G's convey detail with unmatched dexterity. A very special 5U4G (that has found fleeting attention here in the past) is the Tung-Sol VT244. This rectifier delivers a balance and transparency that bests all other rectifiers in my collection. At the moment it equally divides duty with my MB GZ34. Not sure that I can call one better... they're both great in their own uniqe ways. Here is a pic... notice the top getter and two filaments running up between the plates that differentiate it from others of its genre:
My favorable experience with this rare relic has me most enthusiastic about the EML mesh plate 5U4G. Were it to strike the mid point between the VT244 and the MB GZ34, we would be a very happy lot.
Any progress on the hunt, Phil?