If you did splurge, I think you can achieve all of the things you want with one phono stage.
Unfortunately , I think you need to splurge a lot ( unless there's some vintage gear that allows the same flexibility, or a DIY option).
I dont know the details of all of the phono stages that allow multiple inputs, but I can answer your questions with regards to my Brinkmann Edison
- do these offer discrete separation of signals? For example, if I had one arm running a LOMC cart, and a second arm running a high output mono cart, and each was to remain attached to the separate phono stage inputs, does the unit recognize which arm is in use and isolate the second arm?
- I manually switch inputs on the phono stage, via either the remote or a dial on the front
- My understanding is that some phono stages will simply bypass the inbuilt step-up transformer when the MM input is used? Is this the case/
- The transformer can be switched on and off. The Edison doesnt have a dedicated MM input.
- do all multiple input stages have internal switching sets for each input? I can't think of how else this could work?
- I assume they do, but I'm not sure.
- I'd imagine that, even if using a switching mechanism (which may or may not interfere with the signal), one still needs to adjust the phono pre settings according to the arm in use.
- If you use an external switching box, then you'd need to change the phono pre settings each time you switch arms. With the phono stages with multiple inputs, the settings should be saved for each input so you shouldn't need to do anything more than change inputs.
Ultimately, I feel my goal will be to run a LOMC cart on a low-ish mass 12" arm as my main use arm, and a second mono cart (maybe an Orton SPU) on a 10" SME (or similar) arm. I'd love to be able to just whack on a disc, choose the appropriate arm, and be up and running. No switching/changing/adjusting/unplugging. Is this going to be possible?
-This essentially the set up that I have. All I do is change inputs when I switch between my mono cart/arm and the stereo one. This can be done from the remote, so I've occasionally had both arms running at the same time on a mono record, and switched inputs to compare the 2. There's no unplugging,/adjusting/etc.