Hi all, thanks for all the great information. This is my first time posting, and I hope you'll forgive what might be an ignorant question.
I've been very with my Atom Amp+. I've been gradually dialing in a desktop setup, switching my headset back and forth frequently between two computers, and before I tidy it up with a little DIY breakout box with the ports in convenient places, I'd like the community's guidance on this question.
Is it OK that I'm bridging the ground pin of the amplified output to the ground pin of the 3.5mm TRS line in?
In my day-to-day setup, I run a headset with a TRRS plug (Philips X2HR + Vmoda Boompro). The natural way to do this, with a dedicated headphone amplifier in the mix, is with a pair of TRS to TRRS adapters before and after the amplifier, so that the microphone channel of the TRRS connection bypasses the amp. Here's a diagram of my setup.
I really like being able to switch computers with just one switch (a Sescom SES-TRRS-AB, it's basically a passive switch). I'm considering building a little box to cut down on the number of chintzy little adapters in my setup, but before I go to that trouble, I want to make sure that it's kosher to be bridging the grounds in this way. There's really no other way to connect everything, short of:
1. separating the DAC and the microphone ADC,
and
2. moving away from the Vmoda Boompro and its TRRS connector.
In the current setup, if I silence my music and turn the amp way up, there's a bit of noise or interference, but it's well below audible at actual listening volumes; I would only ever notice it if I had the volume from the DAC cranked way down and the amplifier volume way up. I don't think this is ground loop interference (it sounds the same whether or not the microphone bypass is connected), but I thought this might be a well-defined question with a simple answer. Is it OK to bridge the grounds in this way, or is this not preferred?
If something here is unclear or misconceived, please let me know. I'm new to this whole space and it's pretty complicated!