Quote:Posted by: Lon Posted on: Today at 15:46:29
Yes. . . I admit to being a bit confused about the whole rectifier thang in this SEWE300B amp. I had been assuming the Sophia Electric Aqua 274B which I love so much would be fine in that amp, as it is electrically, as I understood it, similar to the 5U4G...
I think at least part of the confusion is that for so long, esp. for the UFO type amps, all the discussion was about the maximum size of the first power supply capacitor, whether (or how close) it was for 47 uF. The actual DC current requirements for the UFO are low, so the only thing we needed to worry about was the cap.
The 300B amp turns that on its head. Now with first PS cap is very small, so pretty much any rectifier checks that box. But the DC current requirement is much more significant, and perhaps too much for many rectifiers.
So when people say e.g. the Aqua 274B is similar electrically to the 5U4G, they were talking about the capacitor rating. There is and has always been a real difference in the rated DC current output, with 5U4G rated for 225 mA. It didn't matter when we were talking about UFOs, it does matter for Sarah.
But note also, that just as the first capacitor rating is more of a guideline than a rule, so is the current rating. I'll never tell anyone to ignore it, but I expect that lots of rectifiers rated for 160 mA would work fine. For example Steve likes the GZ34/5AR4 and it rated for 160 mA.