Any easy way to reduce the output voltage of the Classic Rev6 to 150VDC?

Without changing anything you can lower the voltage to 150 using the "menus" accessed by using the pushbutton (but not from the Web interface). Two issues with this technique: 1) 150 is as low as it will go, you'd be running "bottomed out" on the voltage setting, you may or may not care about that 2) If you do Factory Reset the target voltage resets to 180.

A better way might be to alter the code:

or something along those lines. The HV generator should work okay down to 140 but probably not much lower than that.

Yet another way to do it: Alter the HV feedback voltage divider (R9 and R10). My quick assessment says leave R9 as-is and change R10 to 5500 ohms (5.1K will do if you don't have a 5500 ohm precision resistor), This makes 150V look like 170V to the controller. Should work but the voltage display will be inaccurate, e.g. 150 actual volts will show as 170 "display volts". The idea behind R9/R10 is to make the HV feedback (tagged HVS on schematic) equal 2 volts when the HV is at the target voltage or IOW the controller modulates the HV generator as needed to maintain 2v HVS signal,

EDIT: Schematic here: www.nixieclock.biz/Downloads/C-R6-Schematic.pdf

I would do the hardware change as well. The software adjustment is only really meant for fine tuning.

Thanks Ty!

When you get it working with Pixies we want PICTURES!! Or better yet a short video clip. I think making a Pixie clock out of a Rev.6 is a very cool idea and I'm interested in seeing the outcome.