Brach. Thanks for the thorough information! It would be very helpful if you could let me know which resistors make up the divider.
I put another pedal after the VPM that allowed me to turn down the volume further, and I got what I want. It gave me the full range of the pedal, but also allowed me to use a greater range of the gain controls on the amp. Now I can run the clean channel on my amp with the knob set at something like 4-5 at a comfortable listening level, (and I can even push it higher if I want gentle saturation).
I learned a couple of things for this experiment:
On the positive side, it is easier to adjust the level on the amp when the knobs are at higher numbers. (Without the gain reduction, a premap setting of 1 is a comfortable level, 2 is loud, and three gets complaints from the family/neighbors. The volume curve seems to be flatter at higher numbers.)
My other goal was to get the “better sound quality” that happen when the tubes are run hotter. This experiment debunked that. First, I played it with no gain reduction and the Hot Rod preamp set at 2. Then I used a sound meter and the gain reduction pedal to get the same sound level with preamp set at 5. I couldn’t hear a difference. I think that all the stuff about “the tubes being happier” when the preamp is higher is just that our ears hear things better at moderately loud volumes. (flatter frequency response, and quiet details aren’t lost in the noise floor).
So, I would still like to modify the pedal to get a lower volume output, but now the reason is more pragmatic than achieving harmonic bliss at low levels.
(One more things I learned. when the Hot Rod preamp is pushed to high levels, some of the signal bleeds into the power amp even when the pedal effects loop is at zero. So, if you want dead silence when the pedal is heal down, you can only run the preamp at moderate levels).