Topic: Problem with recorder DC power supplies

[WiFiJeff]

One of the nice but annoying things about the Sonosax MiniR82 is how sensitive its meters are.  I was getting anomolous non-zero readings when feeding it with a digital signal from a V3 with no signal going into the V3, though I could hear nothing.  A friend with good test equipment found that the V3 was an early model without the DC offset circuit engaged, and Grace fixed that for me.

Now I am finding another problem that sounds like the same DC issue that has surfaced with the MR-1 using an external DC power supply.  When I use the MiniR82 internal batteries, or the AC supply Sonosax sells for it, I get zero meter readings on line-in with no signal, but when I use a 5-6V DC supply there is a visible if low intensity response on the meters.  Does this require a fix to the internals of the MiniR82 (as the V3 did) or is there a noiseless DC power supply out there somewhere?

Jeff

[WiFiJeff]

Turns out I should put this on the remote power section.  No problem at all if  I replace my 2005-make Power Stick with a 2007-make but otherwise identical DC Power Stick Li-Ion supply.  Any ideas on what might cause a DC supply to bleed into the audio chain like that?  In Wavelab it looks like a wee spike around 40Hz with smaller spikes at higher frequencies (multiples?).  Could any of this be behind other reported DC supply noise in other digital recorders?

Jeff