Which one to buy: UpTone USB REGEN or Intona USB Isolator?

[tubesound]

I currently have an Empirical Audio Short Block USB Filter for common-mode noise reduction in my system and it made a nice improvement: Short Block USB Filter : Empirical Audio

 

I'm inspired by REGEN and Intona and want to add one of them into my system to further improve the sound.

 

My DAC doesn't need the +5V from the PC side, and so the USB power cleaning won't benefit me much. REGEN is more like an active device and it may have its own sound signature but having all good reviews. Intona (Intona ? Products) claims they achieved galvanic isolation in USB 2.0 high speed mode which makes them world first able to do that. Unfortunately, there's not much info about the details of Intona's design. As there's no off-the-shelf USB isolation chip for high speed, I suspect they implemented their own FPGA solution. From this post: http://www.computeraudiophile.com/f6-dac-digital-analog-conversion/intona-high-speed-universal-serial-bus-industry-standard-cables-connectors-and-communications-protocols-between-computers-and-electronic-devices-isolator-25495/ I learnt that Intona stated the isolator has "probably industrial-wide lowest 8 kHz packet noise". That packet noise reduction is what REGEN is trying to achieve as well.

 

Cost wise, it will be US$196 for REGEN and US$258 for Intona (shipping to Canada included).

 

I'm leaning towards Intona but would like to get your inputs before making a decision.

 

Thanks!

[fakeM]

I currently have an Empirical Audio Short Block USB Filter for common-mode noise reduction in my system and it made a nice improvement: Short Block USB Filter : Empirical Audio

 

I'm inspired by REGEN and Intona and want to add one of them into my system to further improve the sound.

 

My DAC doesn't need the +5V from the PC side, and so the USB power cleaning won't benefit me much. REGEN is more like an active device and it may have its own sound signature but having all good reviews. Intona (Intona ? Products) claims they achieved galvanic isolation in USB 2.0 high speed mode which makes them world first able to do that. Unfortunately, there's not much info about the details of Intona's design. As there's no off-the-shelf USB isolation chip for high speed, I suspect they implemented their own FPGA solution. From this post: http://www.computeraudiophile.com/f6-dac-digital-analog-conversion/intona-high-speed-universal-serial-bus-industry-standard-cables-connectors-and-communications-protocols-between-computers-and-electronic-devices-isolator-25495/ I learnt that Intona stated the isolator has "probably industrial-wide lowest 8 kHz packet noise". That packet noise reduction is what REGEN is trying to achieve as well.

 

Cost wise, it will be US$196 for REGEN and US$258 for Intona (shipping to Canada included).

 

I'm leaning towards Intona but would like to get your inputs before making a decision.

 

Thanks!

 

Check out Sonore website, they seems running promotion event and you get tX-USBhubEX in very reasonabl price, please check!

http://www.computeraudiophile.com/f26-sonore-sponsored/soul-music-universal-serial-bus-industry-standard-cables-connectors-and-communications-protocols-between-computers-and-electronic-devices-hub-25762/

[tubesound]

Check out Sonore website, they seems running promotion event and you get tX-USBhubEX in very reasonabl price, please check!

http://www.computeraudiophile.com/f26-sonore-sponsored/soul-music-universal-serial-bus-industry-standard-cables-connectors-and-communications-protocols-between-computers-and-electronic-devices-hub-25762/

 

Many thanks for the recommendation.

 

After several email exchanges with Daniel at Intona, I've ordered their USB Isolator and I probably will receive it tomorrow.

 

My next DAC will not only provide filtered power internally to the XMOS chip but also have the I2S level galvanic isolation. I believe having the galvanic isolation upstream will further improve the sound.

 

I chose Intona over REGEN in that Intona does almost everything REGEN claimed to achieve and more. Intona have experts in high speed circuit design with many years of experience.

 

Stay tuned.

[tubesound]

Just found another isolator that supports high speed. The isolator(s) seems being a chip rather than in a readily useable form like Intona. Silanna is an Australian company: Isolator

 

Who's the world first? Not important to me.

[tubesound]

Had a brief listening session last night. The initial impression is very positive, quite contrary to the only review online I've found so far: High speed USB 2.0 galvanic isolation. The dropouts Peter experienced are probably due to the fact that Intona has only 300mA output on the isolated side and so if the DAC needs to draw a higher current, this can create a problem.

 

Anyway, first thing first, I can play 24/192 files via Intona and so it does support high speed.

 

The sonic improvements are not night and day kind of change but still easy to discern:

 

1. I hear more details.

 

2. The sound became less congested; for example, vocal and the accompaniment music are better separated.

 

3. The whole presentation of music is more delicate and calmer.

 

It seems the lower noise floor contributes to the above.

 

If this Isolator also has a break-in period, I expect things will be even better down the road.

 

Cheers!

[tubesound]

I've invited Daniel at Intona to participate in this thread so that he can let us know more technical details about this Isolator.

[intona]

I am glad about your positive feedback.

 

My name is Daniel and I am CEO of Intona Technology, Germany and also the head developer of the USB 2.0 Hi-Speed Isolator.

 

Indeed, we were not aware of the post by Phasure and didn't get any direct feedback by him so far. Our accounting says that he has serial no #1 of mid September and we made some changes to the firmware since then - maybe this or maybe your thoughts about power consumption of his DAC caused the issue.

 

There are some audio-specific things I discussed already with tubesound by mail. With his permission, I will quote this here again to the public.

 

> 1. Would the isolator improve the sound quality?

 

The intended purpose is complete isolation of both data and power lines. Resulting sound quality improvement is the effect of breaking all the noise coming from the host computer.

 

As this is a true industrial product, we focus primarly professional applications like automation systems, medical and research labs (even the computer manufacturer with the fruit has one).

But of course, as this product is designed for low noise (research labs need this to gain dynamic range vom nanovolts to kilovolts) and perfect signal integrity, we understand your demand.

We have also some pro-audio and pro-video (4k/high frame rate) customers and they successfully solved noise coupling issues completely.

 

> 2. Would the standard version of isolator meet my needs? In other words, the industrial version could be an over kill for me.

 

The 1kV (standard) version will be sufficient for your application. Even in a classical ground loop situation, there are no potential differences that would require higher isolation to get rid of the loop. Of course, the industrial version has even better connectors and all parts are certified for extended temperature and, finally, every unit has to pass an isolation test with 2,500 volts for some seconds.

 

> 3. Does the isolator deal with common mode noise? I currently have an *********** USB Filter which reduces the common-mode noise in USB cable. Would your isolator make *********** redundant? In other words, would the galvanic isolation filter out common-mode noise?

 

The *********** seems to be audiophile stuff. I don't want to say anything bad about this but nobody would ever use something like that in the industry to get better SNR or the like. Guess why.

Using galvanic isolation is more like wireless. There is absolutely no contact with any computer signal.

As there is 1. a complete new and absolutely silent ground and 2. all power regulators are linear, there is no common noise coming from the isolator. All common noise from the computer is being ripped by the isolation barrier.

While developing the isolator, we took special attention to the noise coming from its data and power lines. We managed to keep the noise as low as possible. See attached plot (http://intona.eu/pub/7054_fft_output.pdf) showing measured output noise. That is, what the power supply of your DAC will see. Your DAC has a PSRR of like > 90dB which you can subtract down from these values.

 

> 4. There's no off-the-shelf USB isolation chip which supports high speed. I suppose you did some FPGA application inside the isolator. Does the isolator do reclocking and DC-DC conversion?

 

Yes, it has two FPGAs built in and it does reclocking. It also has a proprietary DC-DC converter followed by a ADP125 ultra-low-noise linear voltage regulator.

Also be aware that power output of the isolator is limited to 300mA with no voltage drop and 500mA max with voltage drop to 4.5V. This may be a gereneral issue with USB-powered devices.

Further, some non-professional users reported that they need to add a hub before or after the isolator. On subsequent tests in our lab, our SDA 'scope showed us clearly that computers with non-certified USB ports have some really big issues that our isolator cannot solve directly. This happens rarely and mostly with very cheap computer hardware. And as said, can be solved using a good hub.

 

> 5. Then the quality of the crystal oscillator is important too. Are you using, say, Crystek oscillators?

 

It is a SiLabs MEMS oscillator, with measured Jitter around 2ps. This is, because 1. we have some customers that need mechanicly rugged hardware because they use our isolators at repeated >2g acceleration 24h/7d - crystals will fail here - and 2. power consumption of MEMS is 1/10 of crystals. As all voltage regulators are linear in the isolator, we had to pay attention to overall efficiency.

 

Ahem, this clocking thing on USB is an ambivalent issue that I recognize on many forums. All transceiver and hub chips have their own PLLs inside and they all rely on internal RC oscillators to derive the bit clock. We didn't see any change on eye diagrams of the USB bus whether the transceivers where clocked with +-500ps Jittter or +-5ps Jitter on our LeCroy SDA. Anyway, we took special attention to all design aspects and price economy was never a subject.

 

> 6. I chose your isolator over ***** in that I believe your design is superior and it has more intellectual value. ***** claims it can reduce 8KHz packet noise and does impedance matching. I'm wondering whether your isolator also addresses these two issues. BTW, do the two issues matter for USB audio?

 

Our design is completely impedance controlled, also for the tight rules of USB 2.0 which is 90 Ohms for diff/odd and 45 even. We are experts in high speed circuit design with many years of experience.

 

I am aware of this packet noise issue in the audiophiles world. I must say, i never heard about that in the professional world. Correct designed ADC/DAC does not complain or suffer about this. I guess this IS a big issue in the audiophiles world because many hobby designers fail in high speed circuit design, which is also true for analog (audio stage).

 

Okay, nevertheless, we measured this 8 kHz thing early in design stage and did optimize accordingly. See attached power supply plot (http://intona.eu/pub/7054_fft_downstream.pdf) for full downstream utilization using a RME Fireface UC, 8 channels at 192 kHz. There is simply nothing to see at 8 kHz (< 145dBu). So, this is what they wanted with ***** but failed.

Of course, this 8 kHz thing may appear again in a badly designed device after its USB transceiver.

 

Here is a cite from myself to a customer some weeks ago:

+-+-+

At Intona, our business nature is Professional Audio. Thanks to our fully equippped audio lab, we had the chance to take special attention keeping the noise of the power supply output as low as possible in the 20-20k range and we also optimized current flow using a high-speed current sensor probe that resulted in the probably industrial-wide lowest 8 kHz packet noise. We also did ensure the compatiblity to UAC 2.0 devices. Lastly, both XMOS-based and RME interfaces are tested and found 100% compatible to our high speed isolator product as it supports the full bandwidth of 480 MBits.

+-+-+

 

> 7. does your Isolator has a "break-in" period? I know capacitors need time to "loosen up".

 

Due to the industrial target for this product, we use very high quality and long life capacitors. In case of electrolytics, these are Panasonic FP Industrial and in case of multi-layer ceramics, these are high-tech parts from including Samsung Electro-Mechanics America dedicated for high speed signalling. We also always use thin-film resistors in our linear regulators. From industry-view, there will (hopefully!) no change in terms of break-in for years. But from audiophiles view, these will (hopefully!) smooth out for your ears.

 

Thanks again to tubesound for his very good questions.

 

-Daniel

[Panelhead]

I am glad about your positive feedback.

 

My name is Daniel and I am CEO of Intona Technology, Germany and also the head developer of the USB 2.0 Hi-Speed Isolator.

 

Indeed, we were not aware of the post by Phasure and didn't get any direct feedback by him so far. Our accounting says that he has serial no #1 of mid September and we made some changes to the firmware since then - maybe this or maybe your thoughts about power consumption of his DAC caused the issue.

 

There are some audio-specific things I discussed already with tubesound by mail. With his permission, I will quote this here again to the public.

 

> 1. Would the isolator improve the sound quality?

 

The intended purpose is complete isolation of both data and power lines. Resulting sound quality improvement is the effect of breaking all the noise coming from the host computer.

 

As this is a true industrial product, we focus primarly professional applications like automation systems, medical and research labs (even the computer manufacturer with the fruit has one).

But of course, as this product is designed for low noise (research labs need this to gain dynamic range vom nanovolts to kilovolts) and perfect signal integrity, we understand your demand.

We have also some pro-audio and pro-video (4k/high frame rate) customers and they successfully solved noise coupling issues completely.

 

> 2. Would the standard version of isolator meet my needs? In other words, the industrial version could be an over kill for me.

 

The 1kV (standard) version will be sufficient for your application. Even in a classical ground loop situation, there are no potential differences that would require higher isolation to get rid of the loop. Of course, the industrial version has even better connectors and all parts are certified for extended temperature and, finally, every unit has to pass an isolation test with 2,500 volts for some seconds.

 

> 3. Does the isolator deal with common mode noise? I currently have an *********** USB Filter which reduces the common-mode noise in USB cable. Would your isolator make *********** redundant? In other words, would the galvanic isolation filter out common-mode noise?

 

The *********** seems to be audiophile stuff. I don't want to say anything bad about this but nobody would ever use something like that in the industry to get better SNR or the like. Guess why.

Using galvanic isolation is more like wireless. There is absolutely no contact with any computer signal.

As there is 1. a complete new and absolutely silent ground and 2. all power regulators are linear, there is no common noise coming from the isolator. All common noise from the computer is being ripped by the isolation barrier.

While developing the isolator, we took special attention to the noise coming from its data and power lines. We managed to keep the noise as low as possible. See attached plot (http://intona.eu/pub/7054_fft_output.pdf) showing measured output noise. That is, what the power supply of your DAC will see. Your DAC has a PSRR of like > 90dB which you can subtract down from these values.

 

> 4. There's no off-the-shelf USB isolation chip which supports high speed. I suppose you did some FPGA application inside the isolator. Does the isolator do reclocking and DC-DC conversion?

 

Yes, it has two FPGAs built in and it does reclocking. It also has a proprietary DC-DC converter followed by a ADP125 ultra-low-noise linear voltage regulator.

Also be aware that power output of the isolator is limited to 300mA with no voltage drop and 500mA max with voltage drop to 4.5V. This may be a gereneral issue with USB-powered devices.

Further, some non-professional users reported that they need to add a hub before or after the isolator. On subsequent tests in our lab, our SDA 'scope showed us clearly that computers with non-certified USB ports have some really big issues that our isolator cannot solve directly. This happens rarely and mostly with very cheap computer hardware. And as said, can be solved using a good hub.

 

> 5. Then the quality of the crystal oscillator is important too. Are you using, say, Crystek oscillators?

 

It is a SiLabs MEMS oscillator, with measured Jitter around 2ps. This is, because 1. we have some customers that need mechanicly rugged hardware because they use our isolators at repeated >2g acceleration 24h/7d - crystals will fail here - and 2. power consumption of MEMS is 1/10 of crystals. As all voltage regulators are linear in the isolator, we had to pay attention to overall efficiency.

 

Ahem, this clocking thing on USB is an ambivalent issue that I recognize on many forums. All transceiver and hub chips have their own PLLs inside and they all rely on internal RC oscillators to derive the bit clock. We didn't see any change on eye diagrams of the USB bus whether the transceivers where clocked with +-500ps Jittter or +-5ps Jitter on our LeCroy SDA. Anyway, we took special attention to all design aspects and price economy was never a subject.

 

> 6. I chose your isolator over ***** in that I believe your design is superior and it has more intellectual value. ***** claims it can reduce 8KHz packet noise and does impedance matching. I'm wondering whether your isolator also addresses these two issues. BTW, do the two issues matter for USB audio?

 

Our design is completely impedance controlled, also for the tight rules of USB 2.0 which is 90 Ohms for diff/odd and 45 even. We are experts in high speed circuit design with many years of experience.

 

I am aware of this packet noise issue in the audiophiles world. I must say, i never heard about that in the professional world. Correct designed ADC/DAC does not complain or suffer about this. I guess this IS a big issue in the audiophiles world because many hobby designers fail in high speed circuit design, which is also true for analog (audio stage).

 

Okay, nevertheless, we measured this 8 kHz thing early in design stage and did optimize accordingly. See attached power supply plot (http://intona.eu/pub/7054_fft_downstream.pdf) for full downstream utilization using a RME Fireface UC, 8 channels at 192 kHz. There is simply nothing to see at 8 kHz (< 145dBu). So, this is what they wanted with ***** but failed.

Of course, this 8 kHz thing may appear again in a badly designed device after its USB transceiver.

 

Here is a cite from myself to a customer some weeks ago:

+-+-+

At Intona, our business nature is Professional Audio. Thanks to our fully equippped audio lab, we had the chance to take special attention keeping the noise of the power supply output as low as possible in the 20-20k range and we also optimized current flow using a high-speed current sensor probe that resulted in the probably industrial-wide lowest 8 kHz packet noise. We also did ensure the compatiblity to UAC 2.0 devices. Lastly, both XMOS-based and RME interfaces are tested and found 100% compatible to our high speed isolator product as it supports the full bandwidth of 480 MBits.

+-+-+

 

> 7. does your Isolator has a "break-in" period? I know capacitors need time to "loosen up".

 

Due to the industrial target for this product, we use very high quality and long life capacitors. In case of electrolytics, these are Panasonic FP Industrial and in case of multi-layer ceramics, these are high-tech parts from including Samsung Electro-Mechanics America dedicated for high speed signalling. We also always use thin-film resistors in our linear regulators. From industry-view, there will (hopefully!) no change in terms of break-in for years. But from audiophiles view, these will (hopefully!) smooth out for your ears.

 

Thanks again to tubesound for his very good questions.

 

-Daniel

 

Daniel,

Thank you for the detailed explanation. Running a FireWire connected dac currently. But have several USB buss dacs.

[intona]

So, this is what they wanted with ***** but failed.

 

Apologize, this is not my native language. I do not want to discredit anybody. This is not my intention at all.

This is meant in sense of: they failed because of the technically not available ground isolation.

Of course - using any filter, hub or similar may or may not improve any issues. This must be found out by the user individually.

 

-Daniel

[PeterSt]

Hi all,

 

I had a larger post in here but was not confident about whether the content really was for the public eye. So I sent it to Daniel instead.

 

What I can do for the public and for Daniel too, is offering apologies for never complaining to Intona / Daniel. This now looks even worse, knowing that I received the very first one (I did not know that).

So I have been a bit of counter productive.

 

Working on it now ...

Regards,

Peter

[tubesound]

Had some more hours listening through Intona over the weekend and I'm already certain Intona wins my pick for the Product of 2015.

 

I'd call Intona's world first standalone USB 2.0 high speed galvanic isolation device a breakthrough, similar to Gordon Rankin's programming for the asynchronous USB transmission. I felt we're bringing the digital audio playback quality another step closer to that of a great analog system.

[Jimmypowder]

Had some more hours listening through Intona over the weekend and I'm already certain Intona wins my pick for the Product of 2015.

 

I'd call Intona's world first standalone USB 2.0 high speed galvanic isolation device a breakthrough, similar to Gordon Rankin's programming for the asynchronous USB transmission. I felt we're bringing the digital audio playback quality another step closer to that of a great analog system.

 

Damn . There goes another 250 or so ! Lol .

[kilroy]

In use, should the Intona device be closer to the source or the DAC?

 

Would this make the Regen, Jitterbug et al. redundant?

 

If a DAC does not need the 5V line, should it be cut-off at the source, or does it not matter? (My DAC does not, and I block it at the server.)

[Yucca06]

2016 on CA: usb centipede, feat. Intona-Jitterbug-Sbooster Isolator-Regen-Shadow Regen LPS-Curious cable in/out...

 

To be continued.

[elcorso]

Damn . There goes another 250 or so ! Lol .

 

+1

 

Just ordered

 

Roch

[elcorso]

2016 on CA: usb centipede, feat. Intona-Jitterbug-Sbooster Isolator-Regen-Shadow Regen LPS-Curious cable in/out...

 

To be continued.

 

+1

 

Or the never ending

 

The damn USB interface?

 

Roch

[jkenton]

What is "Shadow Regen LPS"?

Is this a second Regen? Or is it a specific LPS for Regen?

As you say- To be continued.

[tubesound]

2016 on CA: usb centipede, feat. Intona-Jitterbug-Sbooster Isolator-Regen-Shadow Regen LPS-Curious cable in/out...

 

To be continued.

 

Haha.

 

Most of the time, more filters are not better. When I read that REGEN and Jitterbug complements each other, my reaction was that they both made design compromises.

 

To me, galvanic isolation is the most worthwhile thing to try for USB audio. Some higher end USB DAC's does galvanic isolation on the i2s level (after the XMOS chip). To me, upstream isolation makes more sense and probably will even improve the DAC's with downstream isolation. I'm getting such a DAC in a month or so and will find it out.

 

With galvanic isolation, I guess the variations in quality with difference PC and USB cable may be reduced significantly.

[tubesound]

+1

 

Or the never ending

 

The damn USB interface?

 

Roch

 

I think asynchronous USB is the best input for computer audio as it has the possibility to keep the jitter to the minimum because after the quality clocks (between XMOS which is mostly used USB receiver chip and the DAC chip), the audio signal is fed into DAC chip directly. Many higher end DAC's do galvanic isolation between XMOS and clocks.

 

USB to SPDIF converters eventually need to feed signals into a SPDIF input which usually uses a receiver chip. The lowest intrinsic jitter of these chips that I know of is 50ps. So the lower jitter you achieved in the converter may be just wasted unless the DAC also does the asynchronous clocking for the SPDIF input instead of using the PLL in those receiver chips. However, these converters also do other things in addition to reducing jitters, say cleaning USB power and galvanic isolation (on i2s level), and so we hear people say quality converters improve sound. To me, Intona is a more economical way to achieve the similar results.

[tubesound]

In use, should the Intona device be closer to the source or the DAC?

 

Would this make the Regen, Jitterbug et al. redundant?

 

If a DAC does not need the 5V line, should it be cut-off at the source, or does it not matter? (My DAC does not, and I block it at the server.)

 

I put Intona close to the DAC side. I use a male A/male B adapter similar to REGEN's to connect the Intona to DAC and this ensures the shortest distance for connection between the two.

 

Whether REGEN, Jitterbug et al. become redundant depends on actual experiment, I suppose. For example, REGEN may not be a true passive device. In addition, the aforementioned devices do not do galvanic isolation. Unfortunately I don't have these devices to try out.

 

My understanding is that Intona also does USB power filtering. But if your DAC doesn't require the +5V, I think you won't get any benefit from USB power filtering. However, I do see explanations on the "dirty" USB power may affect the integrity of data transmitted in the USB cable (may not be the 1's and 0's but the timing). I suppose Intona should take care of this issue.

 

Daniel, could you offer some insights?

[One and a half]

Ordered.

[tubesound]

Just did two experiments.

 

First, comparing a generic USB cable with an audiophile grade USB cable (not very expensive; it's a Bona made in Taiwan) connected from laptop to Intona. Without Intona, I used to be able to tell the difference easily (Bona is way better) but now with Intona, I cannot discern any obvious difference. This verifies my suspicion that Intona will make USB cable less important.

 

However, between Intona and DAC, the USB cable quality may still make a difference.

 

And so, I tried this connection: Laptop > Generic USB Cable > Intona > Bona (instead of the Male A/Male B adapter) > DAC. I prefer the adapter. I think the shortest connection distance achieved by using the adapter contributes to the better sound. And the adapter may avoid another impedance mismatch problem (that Intona has just corrected for you).

[intona]

In use, should the Intona device be closer to the source or the DAC?

 

If a DAC does not need the 5V line, should it be cut-off at the source, or does it not matter? (My DAC does not, and I block it at the server.)

 

Do not cut-off the 5V line. Most devices use this as VBUS detection and they will probably to not work without. The 5V coming out of our isolator is as clean as it would come from a linear wall wart.

 

In gerneral, look at the contacts in your USB cables' connectors. They become dark with time, especially when pulled off and on a lot. Gold plating is very thin and may scrape off. This leads to higher impedance and affects signal quality. USB is prone to errors here because of its nature alternating differential and single ended signals.

Maybe I will do some eye diagram measurements with different cable lengths and aging connectors when there is some time left. This may show some insight from a scientific point of view.

 

-Daniel

[btentusscher]

I am glad about your positive feedback.

 

My name is Daniel and I am CEO of Intona Technology, Germany and also the head developer of the USB 2.0 Hi-Speed Isolator.

 

Indeed, we were not aware of the post by Phasure and didn't get any direct feedback by him so far. Our accounting says that he has serial no #1 of mid September and we made some changes to the firmware since then - maybe this or maybe your thoughts about power consumption of his DAC caused the issue.

 

There are some audio-specific things I discussed already with tubesound by mail. With his permission, I will quote this here again to the public.

 

> 1. Would the isolator improve the sound quality?

 

The intended purpose is complete isolation of both data and power lines. Resulting sound quality improvement is the effect of breaking all the noise coming from the host computer.

 

As this is a true industrial product, we focus primarly professional applications like automation systems, medical and research labs (even the computer manufacturer with the fruit has one).

But of course, as this product is designed for low noise (research labs need this to gain dynamic range vom nanovolts to kilovolts) and perfect signal integrity, we understand your demand.

We have also some pro-audio and pro-video (4k/high frame rate) customers and they successfully solved noise coupling issues completely.

 

> 2. Would the standard version of isolator meet my needs? In other words, the industrial version could be an over kill for me.

 

The 1kV (standard) version will be sufficient for your application. Even in a classical ground loop situation, there are no potential differences that would require higher isolation to get rid of the loop. Of course, the industrial version has even better connectors and all parts are certified for extended temperature and, finally, every unit has to pass an isolation test with 2,500 volts for some seconds.

 

> 3. Does the isolator deal with common mode noise? I currently have an *********** USB Filter which reduces the common-mode noise in USB cable. Would your isolator make *********** redundant? In other words, would the galvanic isolation filter out common-mode noise?

 

The *********** seems to be audiophile stuff. I don't want to say anything bad about this but nobody would ever use something like that in the industry to get better SNR or the like. Guess why.

Using galvanic isolation is more like wireless. There is absolutely no contact with any computer signal.

As there is 1. a complete new and absolutely silent ground and 2. all power regulators are linear, there is no common noise coming from the isolator. All common noise from the computer is being ripped by the isolation barrier.

While developing the isolator, we took special attention to the noise coming from its data and power lines. We managed to keep the noise as low as possible. See attached plot (http://intona.eu/pub/7054_fft_output.pdf) showing measured output noise. That is, what the power supply of your DAC will see. Your DAC has a PSRR of like > 90dB which you can subtract down from these values.

 

> 4. There's no off-the-shelf USB isolation chip which supports high speed. I suppose you did some FPGA application inside the isolator. Does the isolator do reclocking and DC-DC conversion?

 

Yes, it has two FPGAs built in and it does reclocking. It also has a proprietary DC-DC converter followed by a ADP125 ultra-low-noise linear voltage regulator.

Also be aware that power output of the isolator is limited to 300mA with no voltage drop and 500mA max with voltage drop to 4.5V. This may be a gereneral issue with USB-powered devices.

Further, some non-professional users reported that they need to add a hub before or after the isolator. On subsequent tests in our lab, our SDA 'scope showed us clearly that computers with non-certified USB ports have some really big issues that our isolator cannot solve directly. This happens rarely and mostly with very cheap computer hardware. And as said, can be solved using a good hub.

 

> 5. Then the quality of the crystal oscillator is important too. Are you using, say, Crystek oscillators?

 

It is a SiLabs MEMS oscillator, with measured Jitter around 2ps. This is, because 1. we have some customers that need mechanicly rugged hardware because they use our isolators at repeated >2g acceleration 24h/7d - crystals will fail here - and 2. power consumption of MEMS is 1/10 of crystals. As all voltage regulators are linear in the isolator, we had to pay attention to overall efficiency.

 

Ahem, this clocking thing on USB is an ambivalent issue that I recognize on many forums. All transceiver and hub chips have their own PLLs inside and they all rely on internal RC oscillators to derive the bit clock. We didn't see any change on eye diagrams of the USB bus whether the transceivers where clocked with +-500ps Jittter or +-5ps Jitter on our LeCroy SDA. Anyway, we took special attention to all design aspects and price economy was never a subject.

 

> 6. I chose your isolator over ***** in that I believe your design is superior and it has more intellectual value. ***** claims it can reduce 8KHz packet noise and does impedance matching. I'm wondering whether your isolator also addresses these two issues. BTW, do the two issues matter for USB audio?

 

Our design is completely impedance controlled, also for the tight rules of USB 2.0 which is 90 Ohms for diff/odd and 45 even. We are experts in high speed circuit design with many years of experience.

 

I am aware of this packet noise issue in the audiophiles world. I must say, i never heard about that in the professional world. Correct designed ADC/DAC does not complain or suffer about this. I guess this IS a big issue in the audiophiles world because many hobby designers fail in high speed circuit design, which is also true for analog (audio stage).

 

Okay, nevertheless, we measured this 8 kHz thing early in design stage and did optimize accordingly. See attached power supply plot (http://intona.eu/pub/7054_fft_downstream.pdf) for full downstream utilization using a RME Fireface UC, 8 channels at 192 kHz. There is simply nothing to see at 8 kHz (< 145dBu). So, this is what they wanted with ***** but failed.

Of course, this 8 kHz thing may appear again in a badly designed device after its USB transceiver.

 

Here is a cite from myself to a customer some weeks ago:

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At Intona, our business nature is Professional Audio. Thanks to our fully equippped audio lab, we had the chance to take special attention keeping the noise of the power supply output as low as possible in the 20-20k range and we also optimized current flow using a high-speed current sensor probe that resulted in the probably industrial-wide lowest 8 kHz packet noise. We also did ensure the compatiblity to UAC 2.0 devices. Lastly, both XMOS-based and RME interfaces are tested and found 100% compatible to our high speed isolator product as it supports the full bandwidth of 480 MBits.

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> 7. does your Isolator has a "break-in" period? I know capacitors need time to "loosen up".

 

Due to the industrial target for this product, we use very high quality and long life capacitors. In case of electrolytics, these are Panasonic FP Industrial and in case of multi-layer ceramics, these are high-tech parts from including Samsung Electro-Mechanics America dedicated for high speed signalling. We also always use thin-film resistors in our linear regulators. From industry-view, there will (hopefully!) no change in terms of break-in for years. But from audiophiles view, these will (hopefully!) smooth out for your ears.

 

Thanks again to tubesound for his very good questions.

 

-Daniel

 

Would the Isolater be an improvement if I already use the Elfidelity AXF-100 pro USB card with a linear power supply?

[Jimmypowder]

I had a chance t briefly use the Itona USB isolator and all I can say is wow .

An inexpensive e way to add galvanic USB isolation to my Yggdrasil .

 

I have used a lot of tweaks and this one is the best one I've used thus far in tweaking USB .