lol, I'll be damned if I know what exactly my multitude of issues were, but between a powered USB hub, grounded power supply for the Fostex and a Hum Destroyer HD400 I've got a working setup on this PC between speakers/headphones with all my powered speakers. So the YU4s can go elsewhere now...

Just bumping this for anyone who comes across this topic in the future, I fixed all my issues with a Behringer MICROHD Hum Destroyer HD400 :)

Woohoo, finally fixed my issue. The Behringer MICROHD Hum Destroyer HD400 worked. The most important thing is the piercing pop noise is away when skipping youtube videos and so on. This is with USB input and RCA output. No more need for optical. But as a second added benefit I can even have the...

Okay here is something else to chew on, USB from my PC to Fostex but optical out from the Fostex to Kanto YU4. I think the optical out on the Fostex is some sort of passthrough though as volume knob on the Fostex doesn't really work right when using optical out. No speaker popping when seeking...

I just added in a quick third edit above, I totally got rid of the interference from my monitor/GPU by isolating the Fostex and Kanto speakers away from the outlet the PC uses whilst still having both USB and optical cable running to my PC for input. Leaves me back at square 1 though, I still...

Here is a conundrum to throw the cat in amongst the pigeons. The Kanto YU4 which I still have on my desktop as I'm quite enjoying them here for now started to display loud audio buzzing/humming when I booted up a game and my 2080Ti kicks in (high power draw card). This is with optical out from...

Thanks, but no such luck. Same issue with these Kanto YU4 speakers (the audible pop out of one speaker). I asked Fostex for some more help but no one has responded from customer service yet. I guess I might just be sticking to optical only from PC lol. If it's not a faulty unit I have, and I...

While I've had no luck with USB and have now just stuck with optical, I have bought a new set of speakers for another room in the home I will be able to try shortly, the Kanto YU4. So I'll see how I get on with these! Not expecting any difference mind you, but you never know.

Sorry for bumping my own topic but I've just discovered something else playing around with connections. With both USB and optical cables disconnected from the HPA4BL, I can get the pop repeating by simply toggling between USB/optical with the front switch on the HPA4BL. Secondly, I might have...

Hi, thanks for the detailed list of things to try. Your first point is a good one as the Fostex is a USB 2.0 port and cable. Unfortunately just about everything I have is USB 3.0 lol. Even the powered hub I bought is USB 3.0. I will try to see if I can get ahold of a USB 2.0 hub. My PC is...

Hi everyone, This is my last ditch attempt to get some advice on using the USB functionality of this DAC before I just decide to give in and use optical. A short chain kicked off in the dedicated topic looking for help but given low traffic in there I'd like to open up to all of you...

Arrived today, sadly it doesn't help, so I'm all out of ideas. I guess I would need to now troubleshoot by means of trying some sort of input that isn't my own laptop/PC to test if it's all to do with the USB source. I've tried getting my Galaxy S20/Nintendo Switch outputting audio with a USB C...

Just a small update to say Fostex customer service UK are great Here is hoping my USB issues get fixed! Just been running optical in the mean time with no issues. I guess I should probably add I love this wee DAC too :beerchug:

Gotcha, much appreciated with all the advice and things to try. The one thing we have discovered is the plug I have has the fake prong, so it's one of the last avenues I have left for trying. The internet is full of people having issues with DACs and USB, so it seems like it's a minefield. Many...

Thanks. One question I could throw at you is would a grounding problem not manifest itself over an optical connection? I know the answer to many pops, crackles and hums is "just use optical", but I don't know the science behind why that works :beyersmile: Also, I presume a grounding problem...