Following the advice in the QA402 Wiki, I purchased four, 6’ coax cables, & and a couple of 9" cables from PI Manufacturing. I am not using them in a production environment where they get used a lot- just measuring my gear. I recently noticed one channel or another would move around a lot and tracked it down to the cables. I had some “nice” RCA audio cables and hooked them up to the QA402 using BNC to RCA adapters- performance improved greatly, at least as far as stability. The PI cables are very thin and I am guessing the shielding used on the cables is not a lot (assuming they are indeed shielded). The audio cables that I am using are not all the same type (2 different stereo pairs). Not that it makes a big difference, but I wanted to have four of the same cables, mainly when when I use the “right as a reference” FR measurements. Sure, there are lots of cables on Amazon to choose from, but it seems most of the “reasonably priced” ones seem to have some flaw. I am curious what others are using for cables. Right now I am leaning towards getting 4 of these (3’)- anyone had any experience with them?
I suggest you check here: https://www.redco.com
They have fine RCA, XLR, and even BNC connectors that can be used with cables other than coax. Plus, they have great quad-twisted microphone cable in bulk from the likes of Canare and Mogami that is ideal for this application.
You could build your cables from these parts. Or, they offer a cable assembly service. I’ve never used the latter, but it might be worth talking to them.
These guys also sell many of the same parts: https://www.markertek.com
I’ve even had some custom cables made by them. Very good quality.
Thanks for the suggestions. I did not really see what I was looking for though. While I sometimes enjoy making a cable or two, I would prefer to purchase just a few with RCA on both ends 
I either make my own cables with twisted 18-AWG primary wire and RCA or BNC ends or buy the least expensive I can find.
What ‘flaws’ are you seeing?
Typically, one channel would jump around while the other was solid. Then I would check connections and determined that it was sensitive to the cable(s). Ever since I went to better RCA cables my measurements have been more solid. My one set is longer than the other set- I would like too have them all matched- must be the “Monk” in me… Updated 11/6… It turns out Amir at ASR just tested a few rca cables and he did not like the monoprice cables, though they measured the same as the other cables…
The PI Manufacturing cables, at under $2/cable, make it easy to toss them if the cable gets unreliable. Plus, if you put the QA402 into loopback, use a small FFT for really fast updates, set to freq response and you have a killer cable tester. Bend the cable, flex the cable, twist the cable. If the response is as expected and rock solid, the cable lives for another day. But if it shows any strange behavior, it doesn’t hurt at all to throw out at a $2 cable that did its job well 12 weeks.
Thanks for the tips, Matt. If I would have thought about it more when I 1st started, I would have stayed with good RCA cables which I had, as either cable is going to require a bnc to rca adapter, at least for everything I will be looking at. I just want to have 4 of the same cables, though I doubt I would see any difference between them 