USB is noisy…

Paul posted my question in Ask Paul about whether using USB connection from a PC/MAC to a DAC is a good thing to do. Thank you Paul for answering my question. I believe Paul’s response is that using a USB connection would be fine, but, if possible, you should connect to your DAC using the Coaxial or the Optical connection. I purchased my music library from Quobuz in the form FLAC or Apple Lossless files which reside on my PC. How would I best get these files to a place where I could use a coaxial or an optical connection to my DAC to avoid the noise created by the computer?

What DAC do you have? Does it have an I2S input? Do you want a streamer and NAS option? Or all you want to do is connect your PC to the DAC?

For example if you have a MKI DSD DAC you would want a DDC inbetween. That should do it.
if you have MKII many have found the isolation Ted design in the USB input is good enough. A DDC might help here too, but most have said no.

If you have a different DAC with only USB input, there are USB filter options. I do not have much experience with those. Others may offer help.

Most here have gone with streamers and have it access the files from the computer or NAS. You can get them as cheap as $500 or up to $20,000. Tons of options. Many come with their own software and are not that expensive such as the latest node. Or even a used one and use the Coax out of that to the DAC.


also to add there are (or used to be!) PC soundcards with digital output, some on coax some on optical, some built in (PCI cards) some are external (i.e. USB, but with an optical out so noise not a problem).

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USB is not inherently noisy, but coming from a PC/MAC it most likely is. Some of the best streamers and DACs in the world are based on USB. My streamer and DAC are $10k+ and optimised for USB.

I strongly disagree with Paul‘s reply, because the problem is not USB, but the computer. Computers use USB because it is a universal format. Pretty much send any data to any device without practical limitations. PS Audio prefer I2S and coax, But they both have their own limitations in relation to cabling and data rates. I2S is proprietary and works with a few devices from other brands.

Your computer is acting both as server (holds files) and streamer (runs software to deliver them). You seem to be looking to replace both, which can be done with one or two boxes.

There are products to clean computer USB, ranging from AQ Jitterbug to Innuos PhoenixUSB, which you could add to your existing system without any other changes.

A product like Innuos Zen Mini does both Storage and transport with excellent software, and the more you pay for that brands products the better it gets. It’s mostly down to the cleanliness of the power supply and, in the case of USB, the quality of the reclocking.

The other option is to get a streamer and a network storage drive. (my network storage cost less than $200 for 2 TB). The data will then be going to your streamer over an ethernet cable with almost no noise at all and no limitation as to where to put it in your home.

Most streamers allow you to attach a USB drive and will index your music library, but it uses power over the USB. It’s not as bad as using a computer, but not ideal. Others like Holo allow you to add an internal hard drive. Innuos have two ethernet sockets so you can add a network drive directly using ethernet cable (no power - no noise).

Many streamers offer all the connectivity options, and if you’re really that bothered, you can try them all to see which one you prefer. The only issue is if you have a lot of DSD files, Because certain types of cable will not carry that data.

So my general advice would not be focused on just avoiding one issue, but generally consider how to minimise electrical noise throughout your digital system. The best bank for buck is a budget mains conditioner and component isolator. I bought one off eBay recently for $250.


My perception of reality is that USB cannot be glossed over.

That many do the same has never been a sign of quality, but rather of cost reduction or adaptation to specified (worse) standards than would be possible.

If despite USB connection certain devices (other than PC based streaming solutions) sound good, and only because they have been optimized for it, then this makes it clear that exactly this USB connection is the real problem, not the PC. That would be a fact even if optimized USB based solutions would get close to non USB based ones…simply because they only get close by addressing USB’s problems.

It’s at least couple of orders of magnitude easier to build low noise, low jitter digital audio transfer systems from scratch using AES/EBU or I2S over HDMI than it is to get the same quality out of USB (again from scratch). The biggest factors I can think of include that USB runs from a clock which has no relation to audio clock rates, and the processing and comms is very “spiky” or “bursty” in comparison to the dedicated audio protocols which are completely regular. USB also uses the power line as part of its sensing/negotiating so you can’t just have a top notch 5V rail with no noise.

That’s not to say USB can’t be made to perform well – clearly it can – but it takes a great deal of investment on both ends of the connection. It’s a valid question as to whether it’s worth it.

With most DACs, USB offers a big jitter advantage over SPDIF or I2S based inputs because the DAC’s own clock can be in ultimate control of average the data transfer rate (using Asynchronous USB Audio mode). That pretty much doesn’t matter with any of the DS DACs because of the VCXO being adjustable.

By all reports, Ted’s done a magnificent job of eliminating the electrical noise factor on the Mk2’s USB input so at this point with that DAC just use whatever you like best. I’m still flying the Toslink flag (zero electrical noise + DS jitter-magic) on my modified Mk1.

Oh and @jsprouth my entry to good-sounding computer-based audio was via a brilliant little device called an Audiophilleo. Worth having a read about, even if it’s unlikely to be the best option for you in today’s market.

The Taiko SGM Extreme has been considered the world’s best streamer for some years. The cost about $30,000. You can have any output you like, they are installed optionally. They have a user group elsewhere I looked at recently, and the following survey:

@dvorak makes very good points, its about relative advantages, disadvantages and cost.

P.s. I recently purchased the Innuos Pulsar and Holo May Level 2, a pure usb system. No other connection is possible. The Pulsar was new, the Holo used, but not far from retail. The total cost was the same as a new PSA DSD Mk2 DAC in the UK, without a streamer. I am completely overwhelmed by the sound quality, an incredibly low noise floor and a sound almost as transparent as dCS. The Holo DAC has a noise floor 40dB lower than the DSD Mk2 DAC. So perhaps focus on the noise floor of the DAC first before worrying about the cable.

I still stay by my arguments :wink::

  • what most do doesn’t have to be good, mostly it’s rather a guarantee that it’s just cheap or more convenient
  • that there are DACs which are more expensive than other DAC/streamer combos is a fact and not surprising
  • in case the named difference in technical data is true and comparable, the final judgement should be made by sound quality anyway (which as we know CAN be contradictory to certain technical data)

But it’s great that you’re happy with your new stuff. I guess it will be the best for you at least until the next change. We all make changes according to our perception of what’s important, which doesn’t mean others necessarily see it the same :wink:

I made a system change because I built a new music room. The current DAC is only my second standalone DAC. I’m not planning on a third. I’m told we’re moving within 10 years to a smaller place!

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Without diving deep(er) into the preferred connection method, I can contribute my recent experience eliminating the PC from the chain

Dedicated windows pc running Fidelizer>Audirvana>USB cable>JCAT USB Isolator>DAC

Generic switch>nice ethernet cable>Antipodes K22 >JCAT USB Isolator>DAC
Antipodes digital outputs available: SPDIF, AES, TOS, I2S (RJ45) I2S (HDMI)

DAC - Lampizator Atlantic TRP-3
This dac also has AES, SPDIF inputs available (with a trip back to Lampizator, I2S can also be implemented)

Eliminating the pc in favor of the server/player: The increase in performance of the presentation is not subtle at all. In short, I was hearing pc generated noise, that I didn’t realize I was hearing, if that makes sense?Just a profound uptick in overall performance, dropping the noise just clears a path for all the good stuff your system is capable of

I’m am, at heart, an analog guy, but my new digital set-up is making me a believer in digital possibilities…