Okay, before I get in too deep into this project, I want to test first if my PSU can handle 2 channels. I haven't tested the DC-DC PSU with 2 channels + 2 VU meters. So it was a little nerve-wracking to see if it will work or not.
Happy to say it works just fine. I have it powered for several hours now and it just barely gets warm. Touch with your finger the PSU chip and the little heat dissipates away, sucked away by your finger.
Did some load testing and measurements of current consumption.
Baseline: Power ON LED indicator ON. LED still using low-value Resistors, so LED current consumption is a little on the high side.
1 Channel Pre = 117mA @ 12VDC (1.4 Watts) <--- on our earlier 9V battery testing, we got the same numbers (117mA)
2 Channels Pre = 180mA @ 12VDC (2.1 Watts)
2 Channels + 48V Phantom Power ON for both channels (no mic load) = 200mA @ 12VDC (2.4 Watts)
2 Channels + 48V Phantom Power loaded with 2 condenser mics = 230mA @ 12VDC (2.7 Watts)
2 Channels + 48V Phantom Power loaded with 2 condenser mics + 2 VU Meters running = 240-250mA @ 12VDC (3 Watts)
As I have no idea if this 250mA is good or bad, so I looked around the net for comparables. I found the V3 with a listed spec of 600mA with phantom power OFF, and AD converter OFF (and 1000mA PP ON, AD ON)
So I think the 250mA consumption running fully loaded is not bad at all.
Using an ordinary 9V toy battery, 580mAh, this gives us 2 hrs and 20 minutes running fully loaded.
Using a beefier 3000mAh Li-Ion battery, this gives us 12 hours. And with some DVD batteries, 6000mAh, this gives 24 hours of operation time.
Ok..I feel better now, and we shall continue.