Anybody here terminate DH Labs BL-1 cable?

Just some additional comments. I have used the BL-Ag in the past, which is somewhat similar to BL-1, but uses 2 x 23awg solid-core silver. I have done the floating drain wire scenario, but I could never get the cable to sound open enough. I ended up just soldering both the 2 x 23awg solid-core conductors directly to the signal pin of the RCA and soldered the drain wire to ground on both sides of the cable. This really opened up the sound (a single 23awg conductor just sounded too closed in).

Since the BL-1 uses 2 x 20awg stranded conductors, you may not have this problem, but I’ve always found that larger awg will allow more punch/power in the bass and overall better open sound (essentialy, less resistance in the entire cable, and it’s easier and faster for the preamp/source to charge the cable when pushing waveforms). You could experiment with soldering both 20awg conductors to signal pin and soldering drain wire to ground on both sides of interconnect.

On my interconnects nowadays, I always use 2x20awg solid-core for signal conductors (making a 17awg interconnect). This has proved to be the best solution so far.

When I used the BL-Ag I was doing a single-ended RCA cable.  RCA only has one signal conductor, the other is just ground (not negative like an XLR).  Using just one of the 23awg conductors in BL-Ag for the main signal wire (and doing the ground/floating drain solution) was not enough for good sound.  It wasn't until I combined the two 23awg together for the signal wire that it really opened up the imaging/soundstage.  The drain wire was just soldered to ground on each end of the RCA cable.  The drain/ground wire does not necessarily need to be the same gauge as signal.  The ground wire on the RCA doesn't actually carry a signal - it just connects to the ground plane on both source/target circuits.

As far as my own cables are concerned, they are all balanced XLR anyways.  I use two sets of braided 20awg solid-core, so each XLR conductor (positive/negative/ground) has two 20awg wires (6 wires total in the cable).  This proved to be better than just using one braid of 20awg (3 wires total).

@almarg - thinking about this, you're right.  There may be a little bit of current going back and forth on the RCA shield/ground, since this connects to the electrical ground on both source/target circuits.  However, the primary driver of the audio signal is the main signal wire - as it is the only one connected to the input/output legs of the operation amplifier circuits.

@erik_squires - I understand what you're saying.  In a perfect world, it would probably be better ground the shield on only the source end to act as a ground/drain for any EM.  I'm just posing an alternate method for experimentation.  I never had any problem connecting shield on both end of the RCA cable.  In the end, I suppose it's up to whoever is building the cable to decide on isolated drain/shield versus a larger signal conductor with less resistance.