DIN connection

Is there any noticeable improvement for using DIN connections as opposed to RCA input? I’ve got a reel to reel that has the option but I’m not savvy in the area. Any feedback would be appreciated.

 

I can't see how it would have any improvement. If you use coaxial wiring with a shield like RCAs, the RCA connector preserves that configuration, whereas wiring DIN, one has to get the center conductor out from the shield, and "unshield" the shield to twist it into a wire you can solder.

Worse would be if you put a whole bunch of single-ended cables inside one shield, including power cables, paying no attention to the dielectric or impedance.

Twisted pair used in similar-looking XLR has balanced wiring, and with it's inherent rejection of interference, maintaining shield integrity is not as important there.

That being said, the difference between a $1000 RCA cable, a DIN cable, and RCAs made out of lamp cord will be likely inaudible (and I can give you examples where the lamp cord wins).

Claims of "better" can be debunked...:

 

When DIN connectors as a standard option were being phased out of equipment in preference to RCAs (in the 70's) they said that RCAs had better channel separation.

I take a different position to the previous poster - different quality cables can and do make audible differences (although paying huge amounts of money for a cable does not guarantee huge improvements, and differences in cable quality are less likely to be revealed in lower-quality equipment). You are more likely to be able to buy better quality RCA cables than DIN cables.

When I had a stereo with DIN-only input/output, I made a DIN to RCA cable to try to get best quality (rather than using the DIN to DIN option).
If your equipment has RCA and DIN options, I would use the RCA, to try to get the best quality (even though differences may be minimal, cable and connector quality being the same/equivalent).