First post, by keropi
- Rank
- l33t++
Hiya!
I recently got a very nice and small Hama stereo audio mixer, 2x Stereo IN and 1xOUT , perfect for soundblaster + external midi module.
I know it's a basic/simple one but it's small and tbh offers the basic function that I need. But it came without a PSU. I tried using a generic 9v one that I use for consoles and other stuff but it produces a constant triangle-wavish sound (?) (like the example here: http://en.wikipedia.org/wiki/Triangle_wave) that is audible from ~50% of master volume. Clearly too much noise from the PSU , so I tried an original Roland 9v psu from a SC-55. The parasite is still there but more quiet and more like a deep buzz now.
Ofcourse using a 9v battery solves this problem but I don't really want to mess with batteries...
So I just opened the unit , the 9v input is on the upper left side:
From what I know I don't see any input filtering (or it's a very basic one? I assume the diode is to prevent reverse current?) and I was wondering if anyone has any suggestions of how to fix this... maybe add a capacitor or two? Or some filtering component?
Any suggestion will be highly appreciated, thanks in advance! 😊