jamato8
Headphoneus Supremus
The 5AR4 is made for a much larger cap after it. The 5AR4 brings up the voltage much slower, which is very nice for the tubes and also can be used, as mentioned, with a much larger first cap. The 5U4G and other rectifiers of this type need a smaller first cap with a 4uf recommended but since the 6 operates at a lower voltage than many devices the rectifiers were intended for a larger cap can be used but not a great deal larger. I use a 22uf cap and it is about the extent of a safe area. I also discussed this with an importer of a 274B and he said he felt fine at the operating points I mentioned to him but he wouldn't want to see anything larger than the 22uf cap.