Can faintly here sync click track between POs in my crazy setup

I've been trying to setup my POs to sync in a way that maximizes audio quality. Tricky to describe without creating a diagram, but I'll try:

- PO-12 set to SYN1, outputting to a 3.5mm stereo > 3.5mm mono splitter.
- Splitter Tip (left) out: Is click track, going to a Belkin Rockstar 5-way headphone splitter
- Splitter Sleeve (right) out: Is PO-12 audio, going to @darenager 's passive mixer. (Also using a stereo > mono coupler on this channel to get psuedo stereo, instead of panned hard right audio from PO-12)
- All 4 other POs set to SYN4 take click track in from Belkin 5-way headphone splitter
- All 4 other POs output to go to passive mixer
- Also using a FiiO A1 Portable Headphone Amplifier on passive mixer out to boost signal

This rig is cool and works pretty well, giving me an all PO setup that is all battery, needing no external click source (no iPhone click track app or Volca, etc).

However to finally get to the meat of the issue, I can faintly hear the click track generated by the PO12 when I hit play on the PO12. :(.

I simplified my setup to produce the most reduced case as follows:

PO12 (SYN1) OUT -> 3.5mm Splitter: Left channel -> PO-14 (SYN4) IN > Headphones

In this setup I can hear the click track, faintly, but enough that it is clearly audible.

If I do a more traditional setup, I don't hear the click track:

PO12 (SYN1) OUT -> Normal 3.5mm Cable -> PO-14 (SYN4) IN -> Headphones

It works as expected.

So this lead me to believe, maybe my splitter cable is not isolating the two channel well. So as an experiment I tried this:

PO12 (SYN1) OUT -> 3.5mm Splitter: Left channel -> Headphones

And I sure can't hear any bleed over between the channels on my headphones. The click track seems isolated to one channel to me.

I'm pretty stumped at this point. Maybe there is some way that the POs interact with the splitter that my headphones don't. If anyone has any theories, or a known splitter cable that works (I'm using this one: I'd love to hear about it.

Thanks for checking out my crazy setup.

It’s a bit of a rat’s nest, but here’s a photo of the sync setup, which probably explains my sync setup better than my crazy long post did:

In your simplified setup, try grounding the right input channel on the PO-14. The way you described, it seems that input was left floating, which may be picking up interference from the left input (sync).

Ack, totally missed your comment, sorry.

How exactly would I ground the right channel on the PO-14?

I will try to reproduce the issue and get back to you…

Wow, mighty kind of you!

So what i think is happening is this;

in SYN4 the PO are expecting to receive a stereo signal L-Click R-Audio
after you split the signal your sending only a mono Click track to POs

The POs then use mono signal on both L R,
so it uses the Click as both clock and the expected mono audio input.

I think if you were to set the POs at end of the chain to SYN2 (External Device Slave Volcas, iPhone, ect.)
it would solve the problem because the POs are then only expecting a mono Clock signal as input.

I reproduced the issue and confirmed my theory: If you leave the right input channel on the PO-14 unconnected, the sync pulse from the left input channel will bleed into the audio. To fix the issue, either set the PO-14 to SY2 to ignore the audio input, as @DanoP1anO suggested, or ground the right input channel by using a mono P2 plug.

Thanks a ton @DanoP1anO and @punji , I got it working well now I think!

I set the receiving POs to SY2. The click went away, however I ran into a weird artifiact where sync would temporarily get lost and “re-found” again, causing the receiving POs (it was particularly pronounced on the Robot for some reason) to basically “pause” and “unpause” themselves while playing. Not great. I think this is why I assumed SY2 was not the solution originally.

BUT this time I left them in SY2, then moved the mono > stereo converter coupler to the click track channel of the PO-12. This fixed the sync weirdness with random pausing.

I think it comes down to the POs expect full stereo input, not one channel. And you can expect strange things to happen when you don’t give them what they are expecting.

For the record, this is the adapter I’m using to take the click track from one mono channel back to stereo:

Thanks again!