Ok, I am not trying to throw another wrench into things, but by looking at JL's website, the amp can handle the speaker inputs that you would be giving it, without the use of the LOC. There may be no need for a specific piece of equipment. I hope this is helping and not getting in the weeds too much.
This is from the website:
Analog Input/Pre-Out Harness
The Analog Input Harness accepts the following connections:
Line-Level Analog Inputs:
Six female RCA jacks feed a differential-
balanced input section, providing a high degree of input flexibility, and
retaining superior noise rejection. This type of input architecture also
allows the VX700/5i to cleanly accept any analog audio signals up to 16
VRMS, without using a line-output converter.
Preamp Outputs:
Two female, RCA jacks deliver line-level, analog audio
outputs (Max 4 V RMS) that are compatible with most types of aftermarket
equipment. These are configured with the TüN
Software Interface.
Remote:
This connection provides a positive (+12V) turn-on voltage
(475 mA limit) to activate other aftermarket equipment (similar to an
aftermarket head unit’s remote turn-on lead).
Valet:
When connected to negative ground, this input activates the
Valet Mode Preset and will remain active until the ground connection is
removed. This preset is configured
using the TüN