2. analog
  3. 127031-2195

Can I convert stereo to mono for a phono input

My preamp doesn't have a switch to convert stereo to mono.  I would like to switch a stereo signal to mono to set my cartridge azimuth (when using two channels out of phase, this method allows accurate balancing of the channels).  Is there a way to build a simple converter: two RCA female plugs taking a stereo signal and mixing it to mono, output as two RCA male plugs (mono signal)?


I have a test LP that provides a stereo track (test signal) with the two sides out of phase.  All I would need to do is feed that through the mono converter to set my azimuth. 

Thanks for any advice.  Peter

peter_s
erik_squires
16,236 posts
 
Just use a multimeter. Measure the AC voltage across L and R. I’m assuming the test signal is < 1 kHz?

Attach one lead to L center pin and one to R center pin (after preamp) and adjust until AC voltage is minimal.
mb1audio
151 posts
 
If you used a stereo test signal that is identical for both channels, wouldn't that be the same as a mono signal?
erik_squires
16,236 posts
 
@mb1audio they're not the same. They are out of phase, so when added perfectly should be 0.

If one channel is louder than another, the AC output will be greater than zero. Tricky thing but it works. :)

Best,

Erik
erik_squires
16,236 posts
 
OI should also point out that when doing azimuth alignments in other contexts, 0 may actually be impossible due to some noise or impossibly fine misalignment. The goal is to get as close to 0 as possible.
More to discover