JDS Synapse & Neutron V1 USB Isolators Review

[JasonC331]

$70 is not exactly low. If it were $10, then I'd agree with your line of reasoning. However what is low is all relative to your budget, as always.

I am blessed with thinking that it is relatively inexpensive that is true. For me, I have no issue with buying the Topping HS02 and the Neutron. Have two DACs, One Schiit Multibit 2 and a Chord Qutest on a Micro Dell 7020 Plus, they only have USB 3 ports, at Random times if very quiet, I could hear random stuff for tiny bits of time, these have eliminated that. I wanted a $30 flat WireWorld USB cable so win-win for me. I do find it interesting that even if products are proven to do what they claim and with measurements to back that, there is still a lot of flack.

 

[dmitrykos]

At its low cost, I don't see how it can't be a good option to always have one in the chain if you are running single-ended devices.

Minor correction. Balanced connection will also suffer from the ground-loop induced noise but at lesser extent than single-ended because it still shares ground via Ground pin (see pinout examples: https://www.clarkwire.com/pinouts/xlr-audio-pinouts). Only optical (TOSLINK) or galvanic (USB isolator) or isolated power supply of one of 2 AC-powered interconnected devices can fully solve the problem.

 

[HaveMeterWillTravel]

Only if you can hear ground loop induced mains hum or other USB interference noise from your DAC.

If there's no such noise, then an isolator is pointless.

We tend to always assume if there is an issue, it will be clearly audible as "hum".
I can easily see a situation where there is 'sweet spot': just enough for a subtle but audible degradation, but not enough for it to be obvious.

Standard engineering caveat: "ground" loop is generally a misnomer. It can easily happen between two or more devices when there is no ground.

 

[twofires]

While I appreciate the measurements, and that there are more good products entering the market, consistency in framing these isolator reviews would be handy. Back when an Intona unit was reviewed in 2020 it was chalked up as a useless gimmick that does nothing unless you have power/ground loop noise issues, not recommended, shrug panther. 5 years later and these two units that do nothing unless you have power/ground loop noise issues are both recommended, golfing panther. The issue wasn't how the product performed, but rather in the assumed motivation of the purchaser. I always felt like that Intona product was thrown under the bus for the sake of making a statement about audiophile neuroses.

 

[Roland68]

While I appreciate the measurements, and that there are more good products entering the market, consistency in framing these isolator reviews would be handy. Back when an Intona unit was reviewed in 2020 it was chalked up as a useless gimmick that does nothing unless you have power/ground loop noise issues, not recommended, shrug panther. 5 years later and these two units that do nothing unless you have power/ground loop noise issues are both recommended, golfing panther. The issue wasn't how the product performed, but rather in the assumed motivation of the purchaser. I always felt like that Intona product was thrown under the bus for the sake of making a statement about audiophile neuroses.

It's often forgotten that Intona products are developed for industry, medical technology, research, etc., and are not specifically audio products.
I don't know if this is still the case today, but Intona always offered customers a free 30-day trial of the USB isolators.

They also wrote something about the potential effects. If I remember correctly, the measurements were conducted by Matthias Carstens of RME.
https://intona.eu/en/support/answer/1233

 

[Oldson]

just swapped my E50 dac for ADI-2 dac, will i likely still get a benefit from using my V1?

 

[Roland68]

just swapped my E50 dac for ADI-2 dac, will i likely still get a benefit from using my V1?

The only one who can answer this question in your system is you. Either by listening or by measuring. There's no one-size-fits-all answer.

 

[dmitrykos]

Well, if PC is AC powered and DAC is AC powered and neither have isolated power supply or isolated USB port then ground-loop induced noise is quite likely. As @Roland68 mentioned only listening test (you hear some ticks, clicks, buzzing, white noise when PC is connected to DAC but noise disappears when PC is disconnected) or measurement - record output of the DAC and check noise floor with and without USB isolator (use Laptop on battery for recording, it will be isolated recorder and will not cause another loop).

 

[HaveMeterWillTravel]

While I appreciate the measurements, and that there are more good products entering the market, consistency in framing these isolator reviews would be handy. Back when an Intona unit was reviewed in 2020 it was chalked up as a useless gimmick that does nothing unless you have power/ground loop noise issues, not recommended, shrug panther. 5 years later and these two units that do nothing unless you have power/ground loop noise issues are both recommended, golfing panther. The issue wasn't how the product performed, but rather in the assumed motivation of the purchaser. I always felt like that Intona product was thrown under the bus for the sake of making a statement about audiophile neuroses.

One simply can not make any objective statement on how well a filter ( or any type ) will filter without testing it with things to filter!
Can one measure how well a particle filter filters particles without using any particles? No.
What next, testing the performance of oil filters without any oil or acceptable analog?

All it does is test whether or not it introduces it's own issues to the system.

That is why there are established test methods to determine if a power line filter worked by injecting various types and levels of conducted EMI/RFI and measuring the attenuation.

Well, if PC is AC powered and DAC is AC powered and neither have isolated power supply or isolated USB port then ground-loop induced noise is quite likely. As @Roland68 mentioned only listening test (you hear some ticks, clicks, buzzing, white noise when PC is connected to DAC but noise disappears when PC is disconnected) or measurement - record output of the DAC and check noise floor with and without USB isolator (use Laptop on battery for recording, it will be isolated recorder and will not cause another loop).

If by "isolated" you mean no reference between the DC outputs and power/earth Ground, those can often be the worst offenders. You are at the mercy of the leakage currents which tend to be at 60hz and either in or out of phase with line phase.

 

[dmitrykos]

You are at the mercy of the leakage currents which tend to be at 60hz and either in or out of phase with line phase.

Do you mean issue with coupling capacitance? Depending on impedance of the connected USB device current leakage may cause some noise on isolated side but will voltage ripple be high enough to somehow affect USB DACs audio performance? USB DACs will likely filter it out in their power circuit. #66 lists coupling capacitance for various USB isolators.

I did some calculations for AC (220 V, 50 Hz) and noise caused by coupling capacitance effect is still very low but higher coupling capacitance definitely shows the increase of this noise component. Example for 330 Ohm impedance on VBUS (leakage current, voltage ripple of the noise component):

22 pF: ≈1.52 nA, ≈501.6 nV
100 pF: ≈6.91 nA, ≈2.28 µV
200 pF: ≈13.8 nA, ≈4.554 µV
1000 pF: ≈69.1 nA, ≈22.8 µV

It means USB isolators with lower coupling capacitance suffer less from this issue (more low-noise) than those with higher.

 

[Music1969]

I just ordered TI ISOUSB211 based USB isolator from Olimex for 30 euros lol

Outputs 350mA (more possible with ext power input)

Can you test it @MC_RME ?

USB-ISO-HS

USB Low Full High speed isolator 1000VDC for protecting your PC or laptop while connecting USB devices wired to high voltages CE certified

www.olimex.com

 

[LionIT]

I just ordered TI ISOUSB211 based USB isolator from Olimex for 30 euros lol

Outputs 350mA (more possible with ext power input)

Can you test it @MC_RME ?

USB-ISO-HS

USB Low Full High speed isolator 1000VDC for protecting your PC or laptop while connecting USB devices wired to high voltages CE certified

www.olimex.com

Did you get to test it?
I saw that you had a small 8kHz noise on your device.

 

[Music1969]

Did you get to test it?
I saw that you had a small 8kHz noise on your device.

will receive it this week and will test

 

[LionIT]

I just ordered TI ISOUSB211 based USB isolator from Olimex for 30 euros lol

Outputs 350mA (more possible with ext power input)

Can you test it @MC_RME ?

USB-ISO-HS

USB Low Full High speed isolator 1000VDC for protecting your PC or laptop while connecting USB devices wired to high voltages CE certified

www.olimex.com

From the datasheets it turns out that TI USBISO211 has 1,2pF of coupling capacitance and the Mornsun F0505S used for DC-DC has 20pF (100kHz/1V).
The one determined by the PCB is unknown.
So the Olimex USB-ISO-HS shouldn't differentiate much from the other isolators with good measurements.

 

[Music1969]

From the datasheets it turns out that TI USBISO211 has 1,2pF of coupling capacitance and the Mornsun F0505S used for DC-DC has 20pF (100kHz/1V).
The one determined by the PCB is unknown.
So the Olimex USB-ISO-HS shouldn't differentiate much from the other isolators with good measurements.

yes and it is quite a bit cheaper than others

 

[dmitrykos]

Mornsun F0505S used for DC-DC has 20pF (100kHz/1V)

Mornsun DC-DC module operates at 100 kHz (Switching Frequency parameter in its specification) which is inside the common hi-res audio range and may couple into sensitive audio path. Also its Capacitive Load is max 220 uF which is fairly low. Low capacitive load may cause issues with instability of power delivery if connected USB device causes high inrush current (to charge its power filtering circuit for example), or when connected USB device rapidly changes load conditions (common to USB DACs devices - low frequency sounds cause more power drain which is also varying). Common outcome of exceeding Capacitive Load is unstable power due to excessive oscillation of signal.

In comparison, Isolator V1 operates at 600 kHz Switching Frequency and supports max 2400 uF Capacitive Load making it more stable with various load scenarios. Therefore Mornsun based USB isolators will show different (limited) performance based on these aspects.

 

[LionIT]

Mornsun DC-DC module operates at 100 kHz (Switching Frequency parameter in its specification) which is inside the common hi-res audio range and may couple into sensitive audio path. Also its Capacitive Load is max 220 uF which is fairly low. Low capacitive load may cause issues with instability of power delivery if connected USB device causes high inrush current (to charge its power filtering circuit for example), or when connected USB device rapidly changes load conditions (common to USB DACs devices - low frequency sounds cause more power drain which is also varying). Common outcome of exceeding Capacitive Load is unstable power due to excessive oscillation of signal.

In comparison, Isolator V1 operates at 600 kHz Switching Frequency and supports max 2400 uF Capacitive Load making it more stable with various load scenarios. Therefore Mornsun based USB isolators will show different (limited) performance based on these aspects.

Thanks for your competent explanation, very useful.
Olimex USB-ISO-HS allows to use external power supply for the device side (like Neutron also). Assuming to use a galvanically isolated power supply for it, how could the isolation performance of Olimex be considered in your opinion?
Does the presence of Mornsun DC-DC play a role anyway? (the one used to get 5v from host I mean clearly)

 

[dmitrykos]

Assuming to use a galvanically isolated power supply for it, how could the isolation performance be considered in your opinion? Does the presence of Mornsun DC-DC play a role anyway?

DC-DC module is still active when external DC power is attached and works in parallel. 100 kHz switching will still be present. As to capacitive load - has to be measured, whether external power supply will compensate it when capacitive load exceeds max of DC-DC module, i.e. absence of abnormal behavior such as excessive oscillation happening from DC-DC module's side.

 

[LionIT]

DC-DC module is still active when external DC power is attached and works in parallel. 100 kHz switching will still be present. As to capacitive load - has to be measured, whether external power supply will compensate it when capacitive load exceeds max of DC-DC module, i.e. absence of abnormal behavior such as excessive oscillation happening from DC-DC module's side.

Aside eventual power supply issues, the isolation performance could be considered similar? (in relation to capacitive coupling)

 

[Music1969]

DC-DC module is still active when external DC power is attached and works in parallel. 100 kHz switching will still be present. As to capacitive load - has to be measured, whether external power supply will compensate it when capacitive load exceeds max of DC-DC module, i.e. absence of abnormal behavior such as excessive oscillation happening from DC-DC module's side.

How much power can the ext 5Vdc microUSB input deliver?

I use USB power DAC that needs USB 3.0 port (needs 700mA)