There is an easy inexpensive solution to you problem, in my opinion.... Go to a nos tube web sight...[Brent Jesse Studio is one good one],and buy yourself a couple 5R4 rectifier tubes, [12-15 dollars]. I didn't know what to put in my Bandmaster Reverb, which had the 5AR4/GZ34 on the tube chart, [1968 or 69 ].... An amp tech advised me to use the 5R4 and I did and it works great. It draws only 2 amps as does the 5AR4. It drops the voltage on the plates just a little, but I like that.. Makes the amps more soulful to me... I put one in both the Bandmaster and my 1980 Princeton Reverb... Works great in both....The 5R4s that I bought were made by RCA and labeled #1} Rogers Co....#2] General Electric,[GE],... and they were both made in yr. 1950... They will probably last the rest of my life. Try it and see. NOS=good.... new= not so good. In my opinion... Good luck.... Rod
I put a "paper in oil", .015 cap in my Telecaster. It sounds great, because the oil lubricates the electricity and makes it go faster.