Opinions on D2D converters/isolators

There’s a variety of digital-to-digital converters/isolators available with various methods of galvanic isolation used.
I have a Schiit Eitr - very cheap and minuscule, USB->coax with isolation transformers. It does do something, hard to pinpoint, but it certainly does no harm.
Then there’s things like Denafrips Iris, Hermes and Gaia, quite sophisticated and with optical isolation, also reclocking.
Then there’s the variety of isolation methods internal to many DACs.
Then there’s the upcoming PS Audio AirLens.

I wonder how much of an impact stepping up in DDC technology can have.
Apparently a lot, what with all these new products and Paul touting the AirLens so much.

Those of you who’ve tried many different D2D converters/isolators, could you please describe what you experienced, the differences?

I use a USB to S/PDIF protocol converter to significantly improve Spotify Free from my computer to the main system.

When an intermediary is introduced one is adding another source of noise. I have converters elsewhere which require 9V and get the 9v from an LPS plus an IfI DC Purifier to minimise any added noise.

Regarding noise I use Ifi Purifers of various types, AC Purifiers, DC purifiers and even their USB Purifier (to help isolate noise from the computer).

When adding the power supplies and purifiers for the digital converters, was the audible improvement significant, as in, a clearly audible improvement?
If you possibly can evaluate such a thing by some margin: by how many percent does adding the power related improvements to a D2D device improve its sole effect on the sound as a component?
Improve, as in, make its benefits more clearly audible…
(I shouldn’t get tackled with wording like this, improvements are improvements for us, even when no surplus improvement is added but something unwanted is removed to a greater extent. Though that’s an improvement right?)

And about the sensitivity of digital galvanic isolation devices to vibration… Little high-frequency isolation transformers should not be sensitive to acoustical energy, the rational mind says. Surely keeping such a device on a resonant floor won’t induce jitter? That would be utter madness.
The clocks would be sensitive to vibration, though.

Arenith, I have an extremely complex digital 3-way active system. I started on the IfI bandwagon when I bought just one AC Purifier. The first track I played identified a quiet background cowbell that I’d never heard before. I was stunned. I then added two more AC Purifiers, a couple of DC purifiers and one USB Purifier. The final result produces a very detailed sound which is mainly improved in the higher frequencies and the tone (not a word I like) just seems better than without any of the purifiers.

I have a dedicated 240v ring circuit and attach three powerplants (each with a nearby IfI AC Purifier).

A Stellar P3 handles a Melco music server, which outputs USB (the source material is mainly CD rips, i.e. 16/44.1). The USB through a W4S Recovery USB reclocker (fed by a W4S LPS plus an Ifi DC Purifier). This then goes to a Chord M-Scaler (attached to the SP3). The M-Scaler upscales 44.1/16 to 88.2/24 and outputs coax S/PDIF. This then goes to a W4S Remedy reclocker which converts to 96/24, the reclocker is fed from the W4S LPS plus an iFi DC Purifier.

The 96/24 then goes to the DEQX digital crossover. The Crossover works internally at 96/24 (so feeding it with 96/24 avoids internal upsampling). The crossover outputs three coax 96/24 S/PDIF streams.

The DEQX digital crossover is attached to a P10 (for convenience and load spreading the P10 also drives the two 2 channel bass amps (each speaker has a pair of 15" bass drivers directly connected to the amp channels).

The above kit also has a total of five Sunyata Delta NR power cables with their RFI filtering.

The final P10 has three Direcstream dacs connected and a pair of BHK250s connected. All the power cables to and from this P10 are PS Audio AC5s (remember I’m in a 240v country). My aim was to clean up the digital input to the crossover as much as possible but to leave the final dacs and power amps connected without any filtering. You can see that there’s a huge amount of digital processing before hitting a dac and each unit will have added power noise and without excellent reclocking may have added additional jitter.

The above explains the main paths for listening to CD rips. I mentioned using a converter to convert USB output from my computer when using Spotify Free (which sounds crude unless it gets improved).

My Computer uses two USB outputs. One is connected to the DEQX crossover purely for management purposes (e.g. setting of parametric equalisers) and I add an IfI USB Purifier to clean up USB from the computer. The other USB output of Spotify goes to a USB reclocker - it’s a Mutec MC 1.2 (this is powered from the USB and won’t switch do anything until it gets USB power) which purely converts USB to S/PDIF which is fed to the Chord M-Scaler.

To summarise, I’m afraid it’s difficult to say which purifiers provided the most benefit. I think the reclockers (all of which have very fast clocks) all help greatly (IfI make S/PDIF cleaners but I’ve not tried them, as I already had W4S reclockers - I might try the IfI gear when DEQX bring out their new digital crossover at the end of the year).

One final note. The IfI purifiers are not expensive and the cost of them pales into insignificance compared with the cost of the rest of the system.



Well, you certainly convinced me that they provide great benefit in general!

Certainly. Quite something.

Clean power for digital certainly seems to have been good for me, there are loads of ways of doing it. Personally, I use a Shunyata mains conditioner supplying and isolating everything, fibre and clean usb. The result is such that I’ve never even considered DDCs. They are pretty expensive. They have been around for 25 years, so not new. They tend to come from companies using FPGA or ladder DACs, not standard DAC chips.

All my converters are either reclocking or upsampling or protocol converting or acting as a buffered barrier. They’re there for a reason, but, as I said benefit from the cleanest power possible which adds yet more components. I like the Shunyata filtering but not on the final leg, i.e. not to the dacs or the power amps (or the P10 that powers them).

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If I had high-demand amplifiers, I would not use Shunyata, probably high current single output IsoTek. Hearing the exchange rate this morning, I would expect PS Audio’s UK prices to go up pretty soon.

What is clean USB? If the source is a standard computer, it can’t be clean USB even with the best of USB cables, unless at some stage either before or inside the receiving device, something is done to make it clean.

It’s from an Innuos with a linear power supply dedicated to the usb output. Prior to that I used an Auralic device with an external linear power supply. I’ve never used a conventional laptop or desktop computer in my audio system. About 10 years ago I tried a music server that was a pared down PC-type device running Windows Media Player, but got rid of it after a few months.

The cable is not the issue for me. Until recently I was using a Chord cable that cost me $7 about 10 years ago. I changed it a few months ago as I wanted a much shorter one.


Now lots of people are finding that their $500 ebay Mac Mini or old laptop instantly dies when they try and update to Roon 2.0 (or worse tries to automatically update).

I don’t understand people using conventional computers as digital sources. If you suggested to them to use the CD transport in their old desktop computer rather than their PS Audio transport, they’d probably think you mad, but that’s basically what they are doing.

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If I were a rich man…


There are lots of good cheap streamers around, whether those Raspberry things, Pro-jet Streambox S2, Cambridge Audio CXN v2, etc. My son uses my excellent Auralic Aries Mini streamer and DAC. It runds off DC and you can add external linear PS.

No, I mean, if I had any capital to invest in anything other than what keeps me alive.
I’m POOR (to add: ““af””)

As of yet.

I have a stream box s2 - it was relatively inexpensive and sounds great - it can be used as a streamer or as a USB 'detox" device between computer and DAC