24 feet DIN to XLR phono cable for Graham Phantom?

FWIW, Planar speakers have virtually nil radiation to the left and right of the panel, in a plane with the panel. So, you can probably get away with mounting your tt and preamp near the speaker, if you can place them in the plane of the speaker panel. (Hope this is clear to you; if not, I can try again.)

Allnic H3000 is an interesting beast. I do not know for sure that it treats the cartridge output in true balanced differential mode (presence of RCA inputs does not rule this out). As you or someone else said, it does have XLR outputs and the literature does speak of balanced output circuitry, but could be done via an output transformer. I own an Atma-sphere MP1, but I must say I would not consider trying to use 24 ft of phono cable, even if Ralph does bless it.

Dear JB, Dipoles radiate in sort of a figure 8 pattern where the pinched part of the "8" represents the radiation at the plane of the speaker, and the two top and bottom loops represent the radiation patterns in front of and behind the speaker. So you should be ok. This is also why you can get away with having the outer edges of the speakers very near to side walls.

Jimmy, Possibly the converter box you mention contains a transformer, which can effect balanced transmission between your phono and linestages, but I believe the OP was asking about running 24 feet of phono cable, i.e., from the tonearm to the phono stage. The consensus is that this is not advisable, even if one has a fully balanced phono stage, although it is more feasible with balanced lines than with unbalanced ones.

Dear J, I may have lost track of the facts, but I thought your main issue was using very long phono cables, from your tt to your Allnic. And then I thought that you have had a good result moving the Allnic (at least) close to your tt so as to obviate the need for long cables. Once you've done that, I also believe the Allnic has balanced output, so you should be "home free", if you want then to run long cables from it to your integrated amp or linestage or whatever. You don' need no stinkin' converter boxes.