5V3 test vs. 5AR4

I just wanted to share my test of a 5V3 in an ST70 with KT88s, vs a 5AR4:

Line voltage: 120

Voltage across pins 4/6 of rectifier: 716vac

B+ at pin 8 of 5AR4: 416.0 vdc
B+ at pin 8 of 5Y3:   411.3 vdc

In summary, about a 5vdc drop in B+ using the 5V3.

I'll measure on an ST120 soon.

Bill

That's the quiescent B+ but how about under current draw? We don't hear amplifiers when they are quiescent (zero outout).

A good thought - but that's not how I tested this.

I know, but that is how an amplifier operates when playing music. Current is drawn and different rectifiers, with different internal impedances, will sag different amounts of voltage. The output voltage to the smoothing capacitors thus varies according to current draw, which varies according to the music played. So different rectifiers will sound different, and a no-load test will not give a clue as to the behavior of a particular tube.

Again, good thoughts. Please feel free to share your further tests with the group.