RCA vs Phono cable

I have a 30+ year old Pioneer PL-560 turntable in perfect working condition (Shure M97XE cartridge/stylus) My Primare preamp has no TT connections so I just bought the Graham Slee Gram Amp2 SE phono stage with a PSU1 (should arrive Thursday). I will need a pair of interconnects to connect the phono stage to the preamp so I bought a used pair of Synergistic Research Level 1 UEF Atmosphere (RCA) 5ft/1.5m Interconnect cables. Then I saw info on "phono cables." Is there a difference? If yes, what? Should I have bought a phono cable instead of an RCA or a shorter RCA ?
A Phono cable is generally referring to the cable that will connect the turntable to the phonostage.  Often times a turntable will have a hardwired cable, in which case you do not need (and cannot even use) a detachable Phono cable.
My turntable has a hardwired (L & R) cable with ground wire to attach to the Graham Slee’s input. But the "output" cable from the Graham Slee to the preamp is the one I’m asking about. So I'm assuming the "Synergistic Research RCA.interconnect" I bought is okay.

A phono cable has the so called Din 5 connector on the arm side

and RCA (or XLR) connectors for the amp. connection.

The PHONO CABLE must be a very well shielded cable for very low signal, particulary with LOMC cartridge. It is not just about the collectors (DIN to RCA, or RCA to RCA for some tonearms). It’s all about the quality and shielding for 0.2mV (or even 0.05mV) singal from MC cartridges. If the cable is not designed to use with phono signal then you can catch a radio sirnal in your area or some noice. That’s it!

Little bit less critical for MM cartridges, but anyway ... To use with MM you should know the capacitance of the cable for optimal performance.

Also there must be a separate ground cable in a calssic aplication. 
Connect your phono stage to the preamp with whatever regular interconnect you have on hand. The Synergistic Research Level 1UEF Atmosphere (RCA) 5ft/1.5m Interconnect cables cables should work well.
@mewsickbuff  - If you are talking about the cable between your phono pre-amp and your pre-amp input, it is not really a phono cable. It's just like any other line-level connection. Use whatever interconnects you want. The one you purchased should be just fine.
The ZU Mission phono cable I bought is outstanding .
And better than the Mission IC I was using .
@schubert Zu Audio Mission Phono - this is what i use, bought them in rca to rca configuration with ground wire, but replaced connectors to DIN on one side. Great tonearm (phono) cable for MM/MC cartridges.

I also use Mission  Phono mk2 with WBT RCA’s, but this one is much more expensive.
Thanks all, glad to hear the Synergistic Research cable will probably do well. Got the Graham Slee phono preamp this morning and hooked it up with an ancient Red/Black RCA cable and it sounds pretty good. Noticing a lot less snap, crackle and pop and better soundstage than I've ever heard with my vinyl before. Bass is solid and deep. Instructions say the Slee will be operating at its best in about a week. Hope to hear a bit more midrange. Since the Synergistic Research RCA cable is "used" hopefully there'll be little need (if any) for break in.

Another question, my Husband has about a dozen 78 rpm vinyls that were his grandmothers. If I purchased a 3 speed turntable would he need to change cartridges to listen to 78's versus 45's and 33's?
Last question, yes. As in don't try it with your non-78 stylus. I think you can get a 78 stylus for your cartridge.
PS. I’d spend a lot less on a cable than on a turntable and cartridge. In fact, you might try this cable if you don’t get a better mid-range with what you have.
Usually a phono cable has low capacitance per foot as opposed to other audio cables...
the combination of DIN on one end (maybe, depends) and shielding (as noted by Chakster) is the answer.  Phono outputs are tiny and therefore pick up noise easily since they are amplified greatly before they go into the regular preamp (line) stage.  Almost anything benefits from a Faraday shield, but its most useful when the signal is tiny.

But this only matters from the tonearm to the phono stage.  Once it leaves the phono stage a MC signal will be ~ 100X bigger ( and therefor 100X less susceptible to noise) and MC that figure is ~ 1000X/ Yes, 1000.

The output of your pho stage is, ideally , no different from that of a tuner, CD player or line stage device of your choice.  Mostly because it is line stage.

You are not buying a phono cable. You are buying a line level cable.


How does low capacitance effect sound quality?
OK- this is a bit technical, but the cartridge employs a coil and so has a property of coils called 'inductance'. Interconnect cables have 'capacitance'; when the two are in parallel as in this case, they form a resonant circuit. You really don't want the resonance in the audio band (it can make things unpleasantly bright and contributes to ticks and pops)!

So a low capacitance cable will help to keep the resonance at a frequency outside of the audio band (and the higher the better). The thing is, it really should not be ignored and a lot depends on your phono preamp as to how it is able to manage with the ultrasonic noise that will be present because of this resonance. There are techniques for loading the cartridge at the phono input that can reduce the resonance.

This is a bit trickier with high output MM cartridges like yours (the correct loading will be a resistor/capacitor combination) but even if you don't load the cartridge, the low capacitance cable is important!
many good TTs like my VPI aries use standard rca plugs and any cable will work. Shielding will be the highest concern.