Cardas Audio AKG k702 Mini-XLR Headphone Cable - 20ft

I've been using this amplifier for a while now, and loving it, however for a few months now my audio has been crackling while adjusting the volume knob in any direction from 0-100. Any adjustment I make results in crackles and noise (the audio itself still sounds fine when playing music at a set volume). Is this an issue with my amplifier or could it be my DAC or headphone cable? I'm using a Grace Design Balanced Dac and using XLR cables.

I'm new to the audiophile community, would love some help! I'm a pc gamer who will be plugging this into my pc, what do I need to know and what is required? or is it plug and play to a pc easily? Headphones = HD6XX E.G Will I need to buy an XLR cable? or an extra item? Do I *require* a dac this instant? or can I wait a little after getting the amp What else is recommended to add to my audio setup? What dacs are recommended to pair with this amp?

Kinda lost on cables here. I wanted to go for a balanced setup and bought the same DAC in the image (Grace SDAC). In the instructions it says to use the XLR L and R ports. I can't seem to find super small XLR cables (~3 inches?) that can go from the dac to the amp and not have lots of hanging chord. Also finding it hard to find a 3pin mini XLR cable (from my dt1770s) to 4pin XLR in this amp. Am I just looking for the wrong things? First time getting into a mid-tier level setup so I'm definitely new to this.