Hey fellow gearspacers(?),

I am having trouble and I need someone to check my logic and make sure I'm not missing a troubleshooting step.

The scene: I recently (last month) purchased a Ferrofish Pulse 16 so that I could route a headphone mixer (16 analog outs needed) and so I could route the live room preamps back over optical vs. snakes to improve noise floor. This is routed into an RME UFX+. My ADAT channels were empty so this was the perfect scenario for a good price.

The problem: The Pulse16 periodically pops/clicks in a familiar "clock issues" way. It is ruining sessions so I need a solution!

What I have tried:
1. UFX+ is master (44.1khz) - sync over ADAT and set at SMUX1 - 44.1 on the Pulse 16.
2. UFX+ is master (44.1khz) - sync over BNC (75 ohm) wordclock cable and set at SMUX1 - 44.1 on the Pulse 16.
3. UFX+ is slave (44.1khz) - sync over ADAT and set at master SMUX1 - 44.1 on the Pulse 16.
4. UFX+ is slave (44.1khz) - sync over BNC (75 ohm) wordclock cable and set at master SMUX1 - 44.1 on the Pulse 16.
5. Changed optical cables since they are known to be finnicky.
6. Changed BNC cables just in case one somehow went bad.
7. Tried to chain the Pulse16 as the first and last thing in the wordclock signal chain with other converters and by itself.
8. Both ends are terminated since the connection is device-to-device with no splitters.
9. I did have one interesting event: when the Pulse 16 was being fed a signal from another AD/DA via BNC (Pulse16 was connected last in a chain of 3), when I turned the Pulse 16 off, the UFX+ suddenly got a HOT signal from the clock and I had to shut everything down.
10. At one point I had a preamp connected to channel 1 and smelled a distinct "burning" smell. The preamp connected was only outputting a signal at +4dbu and had been previously connected to another interface without issues. I then unplugged and hooked up a voltmeter and it read out right at the regular voltage. Still inconclusive where the burning smell came from but ever since the Pulse16 hasn't worked right. The preamp works just fine as normal.

Nothing has alleviated the issue. What's worse is that the problem manifests in the same way no matter the configuration: works just fine for the first 10-15 minutes, then pops happen rather periodically about every 25 seconds. The longer it is on, the worse it gets. Channel 1 of the analog input lights up and well as ALL outputs on the Pulse16 and on the UFX+ meters. When I disconnect the ADAT out cables there's no issue, so it leads me to think possibly the AD conversion is the issue. The DA seems to be OK.

I am picking up another MIDI cable tomorrow to try to update from 2.04 to 2.06 on the firmware but I'd be surprised if the firmware fixes anything. Also, the sound quality when it isn't popping sounds good. No distortion or any weirdness.

What am I missing? I will try other sample rates on a new session tomorrow but all my current projects are 44.1k.

See if switching the UFX+ from Master to AutoSync and the Pulse16 to Master helps. If not, run SyncCheck Test.

Whatever came of this? I am having a similar issue.

I ended up swapping all the cables. I still have some intermittent issues with pops though. Not nearly as bad as it was though. I also disconnected the BNC cable entirely and just use the ADAT sync.

Overall, I still have it and use it because it's "mostly" functioning as expected now, but I was more than a little disappointed. Not sure I'd buy another one, even though on paper it's exactly what I needed. Would be nice if there was a competitor in this space.

I had 1 cheapie ADAT cable that was giving me some issues. After changing it out, I haven’t heard any issues. Crossing my fingers that I don’t hear it anymore. I hear you about the market offerings in this space. The pulse16 is offered at a very attractive price point, but I don’t believe there is anything else out there like it that is still manufactured today. What firmware are you running?

I had this issue a few years back but and returned it. But the orice point ks so damn reasonable. O heard the issue can be bypassed using madi

I’m actually going to return mine or attempt a repair. The issue came back with full force. Specifically it is the ADAT inputs (1 and 2 inning at 44/48khz). When I disconnect the inputs and only use the outputs (sending preamps back to control room), it seems to be working. So basically no monitoring in the live room. Definitely defeats the purpose. I’m hoping it can be repaired for a modest fee or if Sweetwater can exchange it. It was purchased last year but the issue never really went away. It went from pops every 10 seconds to once every few minutes, but now it’s literally constant now. Must be a bad chip.

Isn't s/mux only for higher sample rates like 88/96? You don't need it for 44/48.

I'd assume that should be true.

Correct, that’s how it is labeled on the Ferrofish though, but that’s right. I did try setting to 96khz and using ADAT 3/4 inputs and it still has the same problem, as channels 1-4 are still using input 1/2. It’s specifically either the physical ports in 1-2 have gone bad or the chipset itself.

Damn that's creepy guys...
Just bought a Raydat and two Pulse 16.
Finger crossed that I wont get this problem cause I never spent as much money on a audio recording interface.

Could you tell me what Toslink cable you choosed ?
Im planning to get the KableDirekt one. I've read that some cables may not perfectly fit with RME toslink connector (too loose).

Did you find a solution?

Many thanks

I just use cheap generic unbranded TOSLINK cables between my RayDAT and Ferrofish (A16), and between RayDAT and RME ADI-2, various other RME units.
Never had an issue TBH
Personally avoided those with pointless large boots (the one that look like jack cable connectors) - they just add weight and cable drag.

Worth an update for future readers: I did end up returning mine under warranty via the retailer.

With the replacement unit, I have had none of the issues from the previous. Every session has been rock-solid. I definitely had a defective unit, and that was confirmed by the retailer following my steps to reproduce the issue.

I hope no one else has to deal with this issue, but if you do and are under warranty, initiate a swap ASAP.