How are we wiring our Mono systems?

Some of my best jazz LPs are in mono, because the greatest jazz artists were at their peak performing years during the 50s, prior to the big change over to stereo. When I play a really clean mono LP of high recording and pressing quality (using only the mono switch on my preamplifier), I can often becoming completely oblivious to the mono v stereo conundrum.  I agree with Mike Lavigne about the issue with comparing mono to stereo using two different cartridges, one for each mode. So even though I do own a decent mono cartridge, I have never used it.

Larry, I own both the mono and stereo LPs of June Christy, "Something Cool", on Capitol.  Like you say, it is quite evident that these were two entirely different studio sessions.  In some cases she even sings the same song differently.

The impedances (input and output) seen by the two devices would be very different in transformer connected mode vs Y connector mode.  That also would affect SQ of course.  I am actually trying to figure out how you would do it with transformers interposed between linestage and amplifier.  When you say "zero gain", I presume you mean 1:1 turns ratio, so the transformer is in essence isolating one device from the other. One problem with using an external Y connector, either between linestage and amplifier or as is done more commonly, between the stereo leads from a tonearm into a single pair of inputs on a phono stage, is just that, impedance gets messed up, because the driven device sees the output Zs of the two driving devices in parallel.  And in the latter case, each channel of the cartridge sees the internal R of the other channel (in the cartridge) in parallel with the input Z of the phono stage.  A good linestage with a mono switch incorporates resistors to mitigate that issue, in mono mode.

Larry, in your Y connection vs transformer experiment, where did you insert the devices?

Why would you want to delete the thread?

You’re making it more difficult than it needs to be, unless you want to listen only to mono LPs. Otherwise I just use a preamplifier with a mono mode switch. Next step would be to use a mono cartridge. Of those there are two types, true mono vs stereo cartridges where the two channels are internally bridged, so you get a mono signal on each of the two pairs of output pins. I personally like and want the mono signal appearing on each of the stereo pair of speakers. And no one hates audiophiles.