Thursday, June 05, 2008 11:11:54 PM (Central Daylight Time, UTC-05:00) ( )
Finally finished wiring the preamp to XLR jacks. Connected to my RP8
active monitor, hooked up a 150-ohm terminated XLR at the inputs to
simulate a mic connected, then crank up the gain and volume to max....
No hum, no RF buzz... even at 72dB gain setting, and even though it's
running and powered by a DC-DC converter PSU and wall wart.
As you can see from the photo, the XLR jacks are right beside the DC-DC converter PSU, and the wires are LAID ON TOP of it!
I am so pleased and happy with this... I can now breathe easily. Oh this is going to be great!!!!
Connected the SC-1 Solo prototype to Channel 1
of my MOTU 828mk2, set the SC-1 Mic Pre gain to 72db max, volume to
max, input XLR terminated with 150-ohm (to simulate a mic) and recorded
the resulting audio in DP 5.
LISTEN TO THE AUDIO SAMPLE
Okay... that noise you're hearing is with the preamp set to 72dB gain..
72!!!! And volume at max. This is not "hiss" recorded with shorted
inputs, or minimum gain...
And to make it even more mind-boggling... all this powered from a WallWart PSU... and a DC-DC converter.
And to visualize what you're hearing...
I am personally amazed.
UPDATE: The spike you see up is most probably 15.734 Khz.... i.e. TV
Horizontal Scan Frequency interference. (I do have a 20" TV a few feet
away, yeah the old CRT kind of TV).