I updated my schematic with current values of components and voltages. As listed in my schematic, I substituted the EF40 for the RF804 tube. The EF40 is the precursor for the EF804 and EF86 tubes and specs similarly. I got nice Miniwatts for $4 and, being the cheap bastard I am, I went with them. The major drawback is the Rimlok socket. They are nearly impossible to find. I just hpoe they sound as good as they spec out. We shall see.
I did some frequency measurements under the following conditions:
Input from my oscillator at 1V Peak sine wave. Osc measures 6.3k static resistance.
No output termination. I'll do one with termination later.
Measurement taken at output of the LL7903 and LL1680 at minimun, mid, and maximum gain settings.
Freq Min Mid Max
in out in out in out
10 .1 .2 1 15(distorted) 1.8 80(dist)
25 .1 .32 1.8 20 1.8 100
40 .1 .48 2.4 120 2.4 120
80 .1 .9 3.2 150 3 150
250 .1 1.2 3.8 140 3.2 150
500 .1 1.2 3 125 3.4 135
1k .1 1.4 1.6 75 1.6 140
2.5k .1 1.4 .75 40 .75 120
5k .1 1.2 .38 20 .38 130
10k .07 1.1 .2 19 .2 120
25k .03 .6 .12 6 .14 75
50k .02 .28 .1 5 .1 50
100k .02 .12 .15 4 .15 15
Max gain will clip the signal at most settings. My oscillator only goes to 1v min so I will have to set up a devider to get smaller signals.