I have been running the MiniDSP hooked up to my system even though I am not using any subwoofers at the moment. This is because the mid bass becomes a bit overpowering in my room as soon as I turn up the volume a bit. I have been using a small wall wart as a power supply for my MiniDSP 2x4 for years now but the noise haven't bothered me at all since I haven't been listening near-field. If I sit a couple of meters away from the speakers I can't hear any noise at all.
I did some googling on the problem and found a thread where some guy suggested powering it with a 9v battery to see if it was the wall wart that was introducing the noise, because apparently batteries are supposed to be a quiet (but not very convenient) power source.
By chance, I happen to have some 9v batteries lying around from my previous O2+ODAC builds.
|The sacrifical cable to the left, a 2.5mm male to 2x2.5mm female cable.|
I started by cutting off the useless 2.5mm female connectors. I mean, have you ever used one of those? Well, I haven't.
|Shielding/ground and signal wire.|
The next problem was how to connect the wire to the battery, without holding it in place with my hands. One of the connectors on the battery allows for winding the cable around it but the other one does not. But as it happens to be, batteries are not the only things I get left after building an O2+ODAC combo. I get spare battery connectors as well. Might as well sacrifice two of them for this experiment.
|Wire soldered to a battery connector.|
|Tape-wrapped and insulated battery connectors.|
My first thought was regarding the age of the battery. I think the battery I tried was from my own O2+ODAC build several years ago. I take it these batteries are not high-end and maybe they lose charge by time? I fetched my DMM to check the voltage.
|3.91 volts, the MiniDSP 2x4 requires at least 4.5 VDC.|
|8.83 VDC, the MiniDSP 2x4 can handle up to 24 VDC.|
I am a bit disappointed with the results, I was really hoping to get rid of the noise with a quieter power supply. I guess it must be the MiniDSP itself making the noise and I will have to delve deeper to try to find a solution to this, because otherwise I wont be able to use the MiniDSP in my current setup.