Yes, the 4:1 output is out of phase with its input. Something I try to avoid with most projects but this one obviously not.
I would not do it exactly as shown on the Muzique schematic. There's no need for a high input impedance into the added "buffer" stage since you already have a nice low impedance output from the previous stage. Using 10k resistors instead of 1M gets the job done and with less potential noise. Only "bad" thing about the schem below is both pin7 and pin2 of the added IC will be sitting at 4.5v, so a bi-polar 1uF for C3 would be a better choice. However, you could change it to 220n or even jumper through it.
One last possible mod if you are feeling crazy - make R19 a 100kA volume control instead. That would give you a master volume for the signal/compression mix. It's something I would have liked to put in the 4:1 but there was no room on the PCB.
I would not do it exactly as shown on the Muzique schematic. There's no need for a high input impedance into the added "buffer" stage since you already have a nice low impedance output from the previous stage. Using 10k resistors instead of 1M gets the job done and with less potential noise. Only "bad" thing about the schem below is both pin7 and pin2 of the added IC will be sitting at 4.5v, so a bi-polar 1uF for C3 would be a better choice. However, you could change it to 220n or even jumper through it.
One last possible mod if you are feeling crazy - make R19 a 100kA volume control instead. That would give you a master volume for the signal/compression mix. It's something I would have liked to put in the 4:1 but there was no room on the PCB.
