3 three channel system, anyone?

Meridian, I know my 861 has it and I am pretty sure some of their other models do as well.

My Fisher tube integrated had a center channel power output in the 60s. You can do this with ANY preamp. Get 3 high quality Y connectors, male to two female. Plug one into the right channel and use one of the female plugs to run your regular interconnect to the amp, do the same on the left channel. Then run the ICs from the other two plugs to the third Y connector and plug it into your center channel amp. It carries a combined L+R signal. You are simply doing externally what the other preamps do internally and will have no more signal degradation than they do, assuming high quality connectors.

Meridian uses and older system called Trifield to accomplish this, it used to come on Yamaha receivers back in the day too, it works amazingly well, simply making a center of the left and right would be silly in my mind but YMMV....

What do you think the center channel is but a combination of the left and right? This is how it was done in the days when 3 channel was common.

Stanwal...If you use a simple Y interconnect you have shorted the Left and Right together. ALL channels will be Left plus Right... in other words Mono. To mix Left and Right so as to get a center signal without screwing up the Left and Right you must use a resistor network.

In my opinion the simplest and best way to drive three front speakers is to use a stereo power amp with the signal of one channel inverted. Bridge the amp with your center channel, and reverse the speaker wires on the channel that you inverted. Your amp will see a low impedance load, but I never had a problem even with 4 ohm speakers.

Another way is to connect the three speakers in a Y configuration. This will not lead to a low impedance load,