Tour of my optimised USB isolation devices

jkeny

Industry Expert, Member Sponsor
Feb 9, 2012
3,374
42
383
Ireland
I wanted to start a tour of some of my new isolated USB products - ISO-HUB; ISO-PS & two world firsts ISO-SPDIF & ISO-DAC (USB isolated SPDIF converter & DAC, respectively).

I tried a tour on here before (in 2012 of my early products) with limited success - not many signed up - will see if there's enough interest in this to warrant shipping etc.

Apart from the world first ISO-SPDIF & ISO-DAC products what's different about all the products is that they are powered by ultra-low noise, ultra stable, over-specified isolated battery power. The difference this makes to the sound compared to even the latest ultra-low noise voltage regulators has to be heard for oneself.

When it comes to improving USB signal integrity only the absolute best stable, fast, noise-free (at all frequencies) power source will provide the optimal result. Powering both sides of the isolation with this quality of power provides the final last bit of improvement.

Further details about my approach & the isolation products can be found on my website.

Initially, I wanted to tour the ISO-HUB & ISO-PS among trusted members of various audio forums to give people a chance to evaluate USB isolation, in general & my approach, in particular.

initially, I wanted to tour them in Ireland, UK, Europe - are there any members here interested? If so express your interest here & I'll try & accommodate




Here's the write-up on my approach from my website:


It’s been on the wish list of many who have tried USB isolation &/or USB reclocking devices & found it has audibly improved their USB audio systems - to eliminate the 3 or more boxes & interconnecting cables needed & combine it all into a single device which incorporates the same functionality. The ISO (isolated) range of Ciunas devices provides this & more.

The concepts:

The Ciunas ISO-HUB provides an all-in-one combination of true isolation of USB 2.0 high speed signals along with the reformation of the USB signal waveform itself.

Combining this technology inside a USB to SPDIF converter or USB DAC is the next logical step & the new Ciunas products ISO-SPDIF & ISO-DAC are exactly this - a combination of the acclaimed Ciúnas converter/DAC with the above ISO-HUB technology.

Finally the new Ciunas ISO-PS is a power source that uses off-grid, isolated, ultra low noise, fast & stable power source to deliver two isolated voltages 3.3V. It is charged from the 5V VBUS of the USB input port.

A stable, ultra low noise power supply is the foundation for all devices to OPTIMALLY improve signal waveform or signal integrity. In these devices this low noise power is provided by very powerful but very safe, batteries which are user replaceable.

In the Ciunas devices, through various techniques, direct ultra low noise, clean power is provided from these sources without any intervening voltage regulators. I have found that using voltage regulator (even the best ones) on the battery output, negatively affects the quality of battery power output. I believe that most digital audio devices require large currents in bursts & it’s important that the power system is capable of delivering these current demands without generating noise. Batteries are capable of this large dynamic current delivery - the batteries I use have 120 Amps instantaneous current capability. The result of achieving this are large sonic benefits in this area of digital audio.

Why?

The Issues:

It seems that there are at least two factors at play - leakage current mitigation & stable, fast, ultra-low noise power (particularly low noise at very low frequencies).

Current leakage is an inherent phenomena in all mains powered equipment - the reason why medical grade electrical devices exist is a recognition of this fact & keep leakage currents within the limits of medical standards - usually < 100 uA for patient safety considerations.

Why are leakage current issues being focused on now when they have always existed in our playback systems? The rise in use of SMPS power is at the root of the problem. These tend to have higher leakage currents than linear PSes. Another factor are the RFI filters needed in order to pass pass certification in devices handling high speed signals & these filters increase current leakage to ground/chassis.

Leakage currents are not the same as the 50/60Hz ground loop noise heard as hum or buzzes from speakers. This ground loop noise occurs when two or more grounds in the audio system are at different voltage levels & a current flows between these points. Leakage currents arise between the AC & DC of both linear & SMPS but are usually higher in SMPS. A small current is “leaked” onto the DC & often flow in signal cables in order to get back to ground or neutral. Leakage currents - it’s not noise identified a separate audible entity but rather noise which is interwoven with the music signal. How this sounds is variable because it depends on the leakage characteristics of the power supplies through which the leakage currents are flowing. In a lot of cases it is perceived as a dull, flat uninteresting sound lacking dynamics, life & vitality.

Off-grid power supplies, such as batteries are one step towards addressing these leakage currents by simply eliminating one of the leakage loop pathways. USB isolators block another leakage current pathway - through the actual signal lines, not just the ground or 5V power line. These two approaches, implemented in digital audio devices, prevent leakage currents from entering the sensitive analogue areas of these devices.

Another current finding in digital audio is that a well-formed digital waveform seems to result in improved sound quality. Why, is not currently known or revealed by current measurements. To achieve optimally formed waveforms requires a low noise, stable & fast power supply as the stable reference needed for generating such clean waveforms.

In my experiments with USB isolators, USB signal cleaners on the outputs always improved the sound. Why? The reason is likely reducing the jitter which all isolators create on their outputs.

My experiments with reclockers/regenerators showed an obviously audible improvement when powered by battery or similar clean, off-grid PS even when these devices use highly regarded, low noise voltage regulators. An even greater improvement was heard when these internal voltage regulator were bypassed & direct battery power applied in certain critical areas such as clock & USB hub chip. I have posted instructions for performing this minor modification on an existing USB reclocker here & those who have tried it have reported the large audible improvements. The importance of this power supply approach cannot be underestimated. I believe that this unmistakably audible improvement in sonics is to do with the very low noise of these batteries particularly at very low frequencies. If you look at all the ultra-low noise regulators datasheets, including the two above, you will see that noise plots stop at 10Hz - they don’t show anything below this frequency & the noise is shown rising from from 100Hz to 10Hz. Extrapolating this slope to < 1Hz will show significantly rising noise levels for these regulators. Ultra low noise regulator datasheets that show noise measurements below 10Hz (ADM7150) show noise of ~30 to 50mV @0.1Hz under light load of 10mA current.

LiFePO4 batteries used in my devices don’t have this issue, staying at ultra-low noise levels all the way down to DC when supplying much higher currents.

The result of optimising all of these approaches - off-grid clean, stable, ultra low-noise & ultra stable power supply; USB isolation; & USB reclocking, is a noticeable improvement & much more realistic sound - a deeper, more 3D soundstage where each element is more naturally portrayed - a portrayal which has an unforced flow & naturalness to it.
 
Last edited:
I thought there might be some interest - guess not?
 
Is the ISO-HUB similar to ISO Reger and iFi iGalvanic ?
 
Any photos ?
 
Is the ISO-HUB similar to ISO Reger and iFi iGalvanic ?
Yes, the same Silanna isolation chip is used & the same manufacturer USB hub chip as used in the ISO REGEN from Genesys Logic (although not the same model chip as Uptone use) - don't know what iFi are using?

The differences are that mine is powered from battery directly (no voltage regulators) which is the optimal way to power sensitive digital chips. You are also getting isolated power in the ISO-PS which powers the ISO-HUB & not as an add-on extra. I also power each side of the isolation chip with individual battery power which again makes an audible difference. I have 4 isolated USB outputs, not just one for connection to other devices.

It's like waiting for a bus - 3 come along at once :)
 
Last edited:
John,

Are you considering developing a ISO Hub Ethernet Broadband Router?

Not at the moment - an ISO-DAC & ISO-SPDIF is keeping me busy
 
The ISO-HUB truly isolates & regenerates/reforms the USB signal before the input to the USB audio device - it is simply inserted before a USB audio device - the USB cable is plugged into the input & USB cable plugged into one of it’s 4 outputs to feed the isolated/reformed USB signal to your USB audio device

It consists of one USB 3.0 port & 4 USB 3.0 output ports which provides 4 USB 2.0 high speed ports that are both isolated & reclocked/reformed.

Both sides of the USB isolator are powered by a low noise, isolated, battery for the very best signal integrity. I have tested this & the power on the ‘dirty’ upstream side of the isolator chip has a noticeably audible effect.

There are two versions available, one with internal batteries & one with external batteries encased with isolated chargers & ancillary circuitry. The internal version is standalone, only requiring power for the internal charger - the external version consists of two boxes - one contains the USB isolator, USB 4-port hub & surrounding circuitry & the second case contains the power source - two batteries + isolated chargers. This serves 2 independent ultra-low noise high current 3.3V power sources to the ISO-HUB & a 6.6V supply of the same quality for powering another device with isolated ultra-clean power. This power source is also available as a separate product ISO-PS - see below

The battery charging is done via 5V USB supply.

To supply 5V at the output ports for downstream USB devices, an external 5V may be plugged into one of the 4 output ports (using the supplied cable) which will then provide this 5V at the 3 remaining USB output ports. This allows the user to control the quality of the USB 5V output.



The ISO-SPDIF consists of the above ISO-HUB technology as well as a USB to SPDIF converter, implemented in one case.The USB to SPDIF converter used is the well-regarded Ciunas converter. This combination provides SPDIF output along with 4 USB isolated & reformed USB output ports - it’s a combination of an isolated USB hub with an isolated SPDIF converter - the first truly isolated USB high speed SPDIF converter to come to market. This configuration allows for a number of uses - it can be used as an isolated USB to SPDIF converter. It can be used as an isolated USB hub with 4 output ports. It again comes in two versions - a one box (internal power) or two box version (external power).



The ISO-DAC consists of the same ISO-HUB technology combined with a USB DAC (the very well reviewed Ciunas DAC) providing RCA analogue stereo outputs along with 4 USB isolated & reclocked output ports. It comes in the same two versions as the ISO-SPDIF above - internal battery power or external battery power. Again, this is the first truly isolated USB high speed DAC to come to market.



The ISO-PS is an external power supply using user-replaceable batteries delivering two isolated 3.3V direct battery outputs with continuous current output ratings of 2 Amps (but huge instantaneous current delivery headroom >120 Amps). These two outputs can be combined for 6.6V output to drive many higher voltage devices with super clean, ultralow noise current. This is the supply used in the two box external (ext) configurations above.

All batteries can be changed by the owner in the above devices - simply open the case, pop out the two batteries from their cases & push in new ones.

All these devices use a 5V input as a charging supply for the batteries. This 5V can be supplied from the PCs spare USB port or from an external 5V PS.
 
First impressions coming in here

"Straight away yesterday I could hear the difference, the 2 words that come to mind are a fuller and natural sounding presentation.
There is definitely more body to music and a very natural sound, dare I say it very analogue but with all the detail and more.
Not sure how many hours you have on the units but it sounds even better today, maybe the batteries are now fully charged but even with them charged it sounds like it is still improving.

It is definitely a step forward from the prototype we have heard on several occasions over the last year."​
 
Hi John, I tried out your DAC a while back. 2 or 3 years ago, can't remember exactly. It was pretty decent. If you have some of your equipment touring the U.S. I would like to give it a try again. How does your new DAC differ from what I heard before?

I also have a Iso Regen coming soon. Probably in another week or so.
 
Hi John, I tried out your DAC a while back. 2 or 3 years ago, can't remember exactly. It was pretty decent. If you have some of your equipment touring the U.S. I would like to give it a try again. How does your new DAC differ from what I heard before?

I also have a Iso Regen coming soon. Probably in another week or so.

Latest brief, initial impression of the ISO-DAC - he will be doing a more in-depth review of it when he has had time to listen more
The sounds coming out of my speakers now makes me want to cry. While I expected to hear a bit of a difference between my dragonfly red and your setup, I was not prepared for what I'm hearing now. It's just brilliant! Nice job.

I don't have a tour of US as there was no interest shown

The ISO-DAC incorporates all the technology of USB isolation plus it has the same Ciunas DAC technology in the same case - it's essentially a USB DAC with incorporated USB isolation Plus it is powered by isolated battery power, not an add-on power supply upgrade. So it addresses two factors identified as audibly affecting USB audio - ground loops & common mode noise

Someone local is receiving a ISO Regen soon so I should be doing a comparison
 
I thought there might be some interest - guess not?

Congrats on making those.

I bet there will be more and more interest in these with some more time.

Been listening to my own isolated USB connector and DIY Linear Regulated PSU for my DAC (+ AC Filter box to tame some of the Leakage Currents) for 6 months or so and grinning ear-to-ear about the big change in SQ, so I know they're a must.

I have seen that you have experimented with batteries (+ no post reg) to clocks and what not. I haven't yet tried that but I found out the internal battery in my iFi DAC is always powering the clock and some other part, so at least that's good, but I am not sure whether there is a little regulator after it in the circuit.

Overall, very satisfied with my little experiments at home, and wish you a lot of success with these products.
 
Congrats on making those.

I bet there will be more and more interest in these with some more time.

Been listening to my own isolated USB connector and DIY Linear Regulated PSU for my DAC (+ AC Filter box to tame some of the Leakage Currents) for 6 months or so and grinning ear-to-ear about the big change in SQ, so I know they're a must.

I have seen that you have experimented with batteries (+ no post reg) to clocks and what not. I haven't yet tried that but I found out the internal battery in my iFi DAC is always powering the clock and some other part, so at least that's good, but I am not sure whether there is a little regulator after it in the circuit.

Overall, very satisfied with my little experiments at home, and wish you a lot of success with these products.

Thanks, they are shipping & the longer version of the above review will appear after the buyer has had a couple of weeks listening - I expect other reviews to be coming in shortly from other customers - some have ISO-HUB & some have ISO-DAC

Yes, I found that the USB signal lines are the most important to isolate - maybe because I run my audio device on isolated power supplies & therefore current loops are not in the picture.
I suspect that common mode noise (leakage current) is likely one of the culprits although the shape of the USB waveform seems to also play a role

Again, yes, I found (& others have too) that with these batteries (LiFePO4) straight, unmolested power is by far the best sounding power source - using a voltage regulator (even the best available) between battery & circuit, noticeably reduces the sound quality
 

About us

  • What’s Best Forum is THE forum for high end audio, product reviews, advice and sharing experiences on the best of everything else. This is THE place where audiophiles and audio companies discuss vintage, contemporary and new audio products, music servers, music streamers, computer audio, digital-to-analog converters, turntables, phono stages, cartridges, reel-to-reel tape machines, speakers, headphones and tube and solid-state amplification. Founded in 2010 What’s Best Forum invites intelligent and courteous people of all interests and backgrounds to describe and discuss the best of everything. From beginners to life-long hobbyists to industry professionals, we enjoy learning about new things and meeting new people, and participating in spirited debates.

Quick Navigation

User Menu

Steve Williams
Site Founder | Site Owner | Administrator
Ron Resnick
Site Co-Owner | Administrator
Julian (The Fixer)
Website Build | Marketing Managersing