RE: Balanced/Differential Outputs
My project requires differential outputs too. I want to document the pins for differential output below. The TLV320AIC3104 has the following pins 27-30
27 - LEFT_LOP
28 - LEFT_LOM
29 - RIGHT_LOP
30 - RIGHT_LOM
The Bela cape exposes the Balanced outputs on the unpopulated header located at J10. I read it to be the following.
BELA JUMPER - DESCRIPTION - TLV320AIC3104 PIN#
J9-0 - LEFT_LOP - 27
J9-1 - LEFT_LOM - 28
J9-2 - RIGHT_LOP 29
J9-3 - RIGHT_LOM - 30
J10-0 - LEFT_LOP - 27
J10-1 - NC
J10-2 - RIGHT_LOP 29
J10-3 - NC
J1-1 - GROUND
Why is this not two three pin molex connectors? (2.54 spacing - just like the other connectors on the Bela). If it were, it would be compatible with the existing conversion cables (for TRS 3.5mm) and also for TRS 1/4", or XLR conversion cables.
- LEFT_LOP, LEFT_LOM, GROUND
- RIGHT_LOP, RIGHT_LOM, and GROUND
I plan on attempting to solder a 4-pin molex header to J9 with a custom cable connecting to J1 (for ground), leading to two Male XLR connectors. This hooks directly to a modern day powered Professional Loudspeaker differentially.
Although I just realized I'll need some DC-coupling capacitors to isolate the AC signal. Are they on the other side of the jumpers? Being that I'll need these capacitors, I might have to design a breakout board for differential output side. Or is that what J10-1 and J10-3 are for? So we can solder a DC Coupling capacitor there before the connection? is J10-1 and J10-3 connected? It doesn't appear to connect to anything.
I ordered my boards and I guess a lot of these questions will be answered when I start working with it. I just want to be ready for the connections, and I plan on helping contribute to the documentation as I find my way around. Cheers on creating an exciting project!
Jay