JDS Synapse & Neutron V1 USB Isolators Review

[howard416]

My Synapse arrived this week. Holy crap it made a huuuuuge difference in my semi-balanced PC setup. Went from hum, buzz, crackling, you name it, to complete and utter silence where I couldn't even tell the equipment was on until I played some music.

In my case I knew something was up with the USB connection since all the garbage went away simply by disconnecting the USB cable. Which is NOT to say that if you don't hear a difference when doing this, that there isn't still a ground loop that might be affecting you (YMMV).

Only problem now, is that I periodically have to disconnect and reconnect the "input" USB cable to the Synapse since my laptop seems to no longer see the device after some period of time. Not a big hassle but still rather annoying.

EDIT: Connecting the Synapse directly to a USB port on my laptop, rather than to a hub, seems to have fixed this. Unfortunately(it adds a bit of inconvenience but goes with the territory I guess).

 

[HaveMeterWillTravel]

Only problem now, is that I periodically have to disconnect and reconnect the "input" USB cable to the Synapse since my laptop seems to no longer see the device after some period of time. Not a big hassle but still rather annoying.

Might it be some power saving mode within windows?

 

[howard416]

Might it be some power saving mode within windows?

Doubtful, since I sometimes don't have an audio output device right after startup.

 

[Basilderat]

Synapse is working very well for me. No USB dropouts whatsoever. Connected from a Surface Pro 4 -> Topping E70 DAC. I didn't have any ground issues, just OCD (a cheap way to ensure clean single ended return). I'm using the 3D printed version. The red colour contrasts well with the uniform black of the rest of my equipment, looks pretty cool.

 

[dmitrykos]

Only problem now, is that I periodically have to disconnect and reconnect the "input" USB cable to the Synapse since my laptop seems to no longer see the device after some period of time. Not a big hassle but still rather annoying.

You could try switching off power saving on USB hub in Device Manager if it is Windows PC and check if this workaround helps. This setting can be on controller and USB hubs:



Why it can help:

Synapse is using TI IC for USB data isolation and its specification tells that TI chip supports L1 Sleep USB power saving mode in addition to L2. On contrary Analog, in specification to ADUM IC (used by Neutron Isolator V1), mentions that ADUM IC supports only L2 Suspend USB power saving mode (when there is no data on USB bus for 3 ms) and does not support L1 - "This mode is not supported by all hosts or devices. In addition, L1 suspend is not supported by the ADuM4165/ADuM4166 because the handshake packets are not detected or interpreted by the isolator". So, TI IC accepts L1 sleep packets from the Host to put IC into a sleep mode and that probably could be a reason of your issue - something goes wrong with sleep/resume states either in isolator's IC or connected USB device, it could be just a coincidence and specific timing issue related particularly to the connected devices.

 

[taisho]

These isolators can get rid of very much audible mains hum, GPU whine, and other ground loop induced noises.

If you don't have such issues, then an isolator is pointless.

If you do, then they're an effective solution.

Could you elaborate on how an USB isolator helps with GPU coil whine?

 

[staticV3]

Could you elaborate on how an USB isolator helps with GPU coil whine?

They don't help with acoustic coil whine.

But there are many cases in which people can hear GPU activity as clicking/screeching through their USB DAC.

Putting an isolator in between will stop that.

 

[howard416]

They don't help with acoustic coil whine.

But there are many cases in which people can hear GPU activity as clicking/screeching through their USB DAC.

Putting an isolator in between will stop that.

I don't know if it was a ground loop causing anything of the sort, but I do recall before that I had situations where clicking my mouse would make noise in my speakers, and no, I didn't have any microphones on.

 

[HaveMeterWillTravel]

They don't help with acoustic coil whine.

But there are many cases in which people can hear GPU activity as clicking/screeching through their USB DAC.

Putting an isolator in between will stop that.

I would assume one of the main variables is simply either how much current is being drawn, or how fast it's changing (high di/dt) by the card and the system.

I don't know if it was a ground loop causing anything of the sort, but I do recall before that I had situations where clicking my mouse would make noise in my speakers, and no, I didn't have any microphones on.

If it only happens the first time such as when you sit down, then there's a good change it's a mild ESD type event.
It is persists and is occurs when one is in physical contact with the keyboard or mouse (wired), then it may involve the capacitive coupling between your body and the system.

 

[howard416]

If it only happens the first time such as when you sit down, then there's a good change it's a mild ESD type event.
It is persists and is occurs when one is in physical contact with the keyboard or mouse (wired), then it may involve the capacitive coupling between your body and the system.

Consistently.

Can you explain more about this capacitive coupling between my body and the "system"?

 

[HaveMeterWillTravel]

Consistently.

Can you explain more about this capacitive coupling between my body and the "system"?

Your body is basically a large wet sack (electrically speaking). The DC resistance across dry skin is in the 1 Mohm range, and typically has around 200 pF of capacitance. By touching something, you introduce a small but measurable electrical change. Most modern touch screens use a fine grid system to detect where your finger is touching it.
It generally is not a problem (used to be along time ago), and really only has an effect when the specific conditions are just right.

The other way it could influence the system and possibly cause noise is simply due to the change in electrical signals of the keyboard/mouse, or by the content on the monitor changing. For example, if it still happens with a wireless keyboard/mouse.

It's improbable for any particular person or system to experience it, but it can happen.

btw: I've heard it could have a similar effect on old style TV antennas by changing the electrical parameters enough. So you adjust it to get it perfect, but when you let go it gets bad reception again. Sounds plausible, but it could also be incorrect.

 

[howard416]

Your body is basically a large wet sack (electrically speaking). The DC resistance across dry skin is in the 1 Mohm range, and typically has around 200 pF of capacitance. By touching something, you introduce a small but measurable electrical change. Most modern touch screens use a fine grid system to detect where your finger is touching it.
It generally is not a problem (used to be along time ago), and really only has an effect when the specific conditions are just right.

The other way it could influence the system and possibly cause noise is simply due to the change in electrical signals of the keyboard/mouse, or by the content on the monitor changing. For example, if it still happens with a wireless keyboard/mouse.

It's improbable for any particular person or system to experience it, but it can happen.

btw: I've heard it could have a similar effect on old style TV antennas by changing the electrical parameters enough. So you adjust it to get it perfect, but when you let go it gets bad reception again. Sounds plausible, but it could also be incorrect.

Ah, I see. But the (extra) noise wouldn't happen just from holding onto my mouse or keyboard, just from actually clicking (actuating the microswitches under the mouse buttons).

 

[dmitrykos]

When I am not using USB isolator and thus have a ground loop in this setup [PC -> DAP -> powered Speakers] then I can easily hear noise (like modem communication) from external speakers when files are being copied to my DAP over USB, there is no even physical interaction between human and equipment at that moment. It is not about ESD issue. USB communication is a burst of changes in voltage on USB bus, those changes induce additional noise. Clicking mouse is also a kind of USB event which causes electric activity in PC, not just in USB bus but also CPU, GPU which process the event associated with a mouse click. Ground loop provokes very easy induction of the noise from whatever is oscillating in the device.

 

[dapost]

Would a Class II device such as the Wiim Ultra stremaer benefit from a USB isolator?
(I am using the Wiim's USB out to connect to an external DAC.)

 

[staticV3]

Would a Class II device such as the Wiim Ultra stremaer benefit from a USB isolator?

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.

 

[Roland68]

Would a Class II device such as the Wiim Ultra stremaer benefit from a USB isolator?
(I am using the Wiim's USB out to connect to an external DAC.)

The answer is always the same: if you don't have an audible problem, it's no use.
You can't fix a problem that doesn't exist.

 

[JasonC331]

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.

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. Seems like the best isolators have been shown to improve the signal and provide a stable clean signal. I think most would agree that this is a better purchase than a fancy USB cable.

 

[CedarX]

I think most would agree that this is a better purchase than a fancy USB cable.

I would disagree. As @staticV3 said, if I have no issue with noise, the isolator is pointless and to me, it ain’t fancy at all. A fancy USB cable is as much pointless, but at least it’s fancy. Pointless/not fancy vs. pointless/fancy, the USB cable wins for me!

 

[Antagron]

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. Seems like the best isolators have been shown to improve the signal and provide a stable clean signal. I think most would agree that this is a better purchase than a fancy USB cable.

$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.

 

[Basilderat]

$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.

They are available in a 3-D printed version (red case, looks great, same electronics) for $49