MS HELPER

I love MS for guitar, but I used to have a console available for it - thats not really a given these days, so... While considering some handy projects to do, I thought a nice 2 in 2 out MS-LR converter would be nice. Using it after your preamps, before the converters, you can set up for MS, and roll it in as stereo.

The design includes a phase correlation meter circuit, and you can adjust gain on the M or S side to adjust the balance if you like Schematic (rev 2) - Here

BOM - Here

Switch Values - Here

Front panel files for a Modushop Galaxy Case Front - Link

Back - Link

You can get it into a much smaller case - I just hate to build prototypes and one-offs to a tight fit. The dimension for the PCB Mount XLR (if you want to use them), are in the file though. The meter.

The meter reads fully correlated at max, and only detect variations in phase, not amplitude. It will work down to about 50mV with no modifications.

Calilbration

Dont install the THAT1240 ICs, jump connections on the sockets as shown in this image. (pin 2 to pin 6 on the first 1240, pin 3 to pin 6 on the second)

• Inject a signal to one side, and calibrate the meter for center

• Inject a signal to the other side as well, and verify the meter is at max

• You may need to make a small compromise here, since your meter probably wont be 100% accurate (nothing that will matter when its actually in use).

  
  

You can also use an LED meter, something built on the LM3914 would work well.