My object is to combine the right and left channel coming from the preamp into one combined mono channel. I want to do this so the preamp left and right channels remain separated as they are fed into a stereo power amp. -BUT- I want a combined mono channel to feed into another mono power amp to power a 3rd channel to be used as a subwoofer.
I know that using capacitors will allow leakage from the left and right channels into each other, and cause a loss of stereo separation. Resistors will help with the separation, but will cause a drop in output from the preamp. I know that using a single diode from each channel (t othe new center channel) will cause clipping, similar to the fuzz tone sound used with guitars.
Then it occurred to me. A bridge rectifier will allow both the positive and negative halves of a wave to both pass thru, but not allow the signal to go backward.
Will this work?
In other words, I put a bridge rectifier on left channel to the new 3rd channel, then do the same thing on the right channel. Thus, two bridge rectifiers are used. One to the left, one to the right channels, and the two rectifiers are joined in the middle, which then becomes the new mono
3rd channel. The left and right channels coming from the preamp are then fed to a stereo power amp in the usual manner. The combined 3rd channel is then fed to a separate mono power amp.