One of the drivers might be out of phase with the other, ie. wired up backwards.

Any pot will still make crackling sounds with enough DC across it. Try putting a capacitor in there for AC-coupling, and see what difference it makes.

If 16mm is small enough, then TKD 16mm audio pots are very highly regarded, although I've never wanted to spend that much myself (about twice the price of an alps RK27).   If going for 9mm, then Alps, Bourns, Vishay are all pretty good imo. Just make sure to get the proper audio 'A' taper.  ...

Page 20 & 21 of this thread have some

Pretty sure all of ipads are usb audio class 2 compliant, and will support 24/192, the lightning based ones certainly do. You might need to use a USB hub after the camera CC, otherwise get the "this device uses too much power" error. 

Tip & Ring both to +ve Sleeve to ground

All the things you shouldn't do with a microwave are always the most fun.

Well I'm all out of ideas now. Good luck eliminating this gremlin.

This sounds like there is DC current across the pot, which would be due to the DC-offset from your source. A film cap on each left & right input leads, before the pot will AC couple them, and should get rid of the scratching. 2.2uF would be my preferred value for a 50k pot, but anything...

Gainclone is a speaker amp, not headphone amp

B-spec opamps are either higher binned, or specifically trimmed for better DC specs. AC performance is what matters for audio. For typical audio applications, I can't see a valid reason to pay the extra, go with A-spec.

You would need a ratchet crimping tool, with the correct sized hex die for the SMC connector.   Crimping of coax cable is pretty standard, but using normal stranded wires with a crimp connection designed for the shield of a coax cable won't be a guarantee for a secure connection anyway.

Skylar,   How much does the Nighthawk's performance suffer when driven from higher impedance (resistive) sources? Is there a significant/noticeable boost at low or high frequencies in output level or THD when driven from 10 ohm or 33 ohm source?

A single button remote is just a momentary switch shorting out between mic & ground.

1: Shield 2: + (non-inverted signal) 3: - (inverted signal)   yes wire 1-1, 2-2, 3-3   The casing for the xlr connector will usually also have a solder tab, better to leave this disconnected IMO.   More than you ever wanted to know about balanced connections. http://www.rane.com/note110.html

Maybe get a replacement cable for a dj/studio set of cans that come coiled? You should be able to source an AIAIAI replacement coiled cable in europe pretty easy I should expect.

What 4-earpiece headphones do you plan on using, and which 4-eared species is your target audience?

For digital cables, use properly spec'd cable, simple.

What is the input impedance of your amp? It's probably lower than the value of the pot (maybe 10k or 20k) which is going to completely mess with the attenuation slope of the pot. If that's the case you'll need to use a buffer between the pot and amp (opamp stage set to unity gain, etc)

Take a photo of your wiring. What model pot is it? Does the value have a letter suffix such as 'A', 'B; or 'C', etc?

MacGyver would've used a paperclip and duct tape, but I'll give you a pass mark anyway.

focus on the sound of one wire braiding and you shall achieve perfection

Resistance is measured in ohms, its inverse is conductance, measured in mhos (mho is simply ohm spelled backwards, equivalent to 1/ohm).   The inverse of conductivity is resistivity, not resistance. Resistivity would be expressed in ohm*metres, and conductivity being the inverse, in...

Be very careful using petroleum products - ie. vaseline, around cables. Your standard PVC insulation won't like it very much.

connectors > RF > coaxial > MMCX quite a few there