I Need an XLR Digital Cable.

Q1. Has any one started with a $20-30 one then later tried $100 cables and see a (big) jump in performance? I’d like to hear from those whom actually did the A/B tests. 

Q2. Should I start with the under dog, no name brands, hyped or should I start with big name brands’ entry levels? 

I’m using 1 analog XLR cable as a digital cable from MIT MI-330 to play/ verify the benificial of having a DAC .... and it sure is. 
(Ayre cx-7 CD player only provides 1 XLR as digital output source. )
IMHO, I would buy an entry-level first, something made from Mogami or Canare 110 ohm cable. This will get you going with a decent proper connection for cheap. That also gives you a reference should you try something with a return privilege.
Thank you @tls49
I just won eBay some entry level ones (junks?) to test out then will move on up from there.
. Sommer Cable Binary 234 from Germany, $32. (Not so popular here in US so hoping it’s a bang-for-buck.
. Canare DA206, 110ohm, $25.
. Mogami w3080,110 ohm, blue, $20
If I find these entry level digital cables perform worse than my loaner analog XLR MIT Mi-330, I don’t know what to say...

Next on radar:
. Wireworld Starlight 7, $100
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Now, I agree with Kosst_amojan and ev1 else in here. I’d like to reaffirm that while subtitute ANALOG cables for DIGITAL is do-able, the result was horrible. I’m the OP and would like to update.
While waiting on my xlr DIGITAL 110 ohm aes/ebu cables that I won from eBay to arrive, I next-day a $6 xlr to rca adapter from Amazon so I could, meanwhile, re-use my good & decent entry level DIGITAL 75 ohm S/PDIF rca cables that I already have and the result was astounding. They put my ANALOG xlr MIT Mi-330 to a shame. The music from my DAC was just now so beautiful and enjoyable and I could listen for hours. (it’s already 5am and I still could not get up. Go figure! ) Thank you ev1