Hi
Does such a thing exist as a USB power hub that isolates ground loops between each socket?
With the growing number of USB powered devices what we now need to power from separate USB power sources to avoid ground noise loops, it would be really handy to have a single hub to plug multiple devices into for power that aren’t then buzzy as you connect their audio cables.
I see a few similar deep history topics on this already, but in 2022 there are a lot more devices that are USB power only (or via a USB ripcordz type cable) and a specialist audio USB hub would be very useful, rather than buying multiple dongles to insert in the audio loops to quieten the ground buzz in your table of toys…
I’ve a feeling one approach to this might be quite expensive as effectively such a device would need each usb socket to have an internal independent transformer from the mains … but still for many, would be worth paying for rather than 5+ separate usb chargers connected to the mains
I was searching for this kind of product for months but no success yet. I think the problem is that the only people who would benefit from such a device would be in fact us electronic musicians while the vast majority of similar products out there is for the casual consumer mass market. I could totally see myself power my whole mobile setup (Oxi One, TR-8S, Blueblox, Blackbox, Typhon, DigiTone) with only a single, isolated USB brick. If you’re thinking that this isn’t possible because the Ripcords can’t provide enough power, I want to introduce you to the new Birdcords which can handle USB power delivery Power Supplies | Songbird FX
A few days ago, I actually texted the creator of the birdcords if he can think of any solution for this ground loop issue. He didn’t knew anything specific but he feels actually a little bit tempted to build such a device. Maybe more of us should speak up to show that there’s a market for that?
It’s a nice idea, and you’re not the first person to think about this.
But such a device would barely be possible, let alone financially viable.
The problem is that USB isolation chips are not only very expensive, they only work at a single specific transfer rate that has to be selected by hand.
As far as I know, a single isolation chip supporting all common USB transfer rates does not exist.
With just USB 1.1, a hub could be done although still very expensive.
If you also want USB 2.0 and 3.0, price and complexity would go up exponentially.
In fact, price would go up so far that you might just as well put some nice Lundahl transformers into the signal path.
An 8-channel transformer bank like the ART T8 is already cheaper than a single USB 3.0 isolator.
If you just want the USB power, I could see the benefit of having a single power solution with multiple isolated USB outputs.
In that case there would be no need for isolation chips.
But internally that would just be multiple chargers in a box, which can be done DIY very easily.
I’m not sure if @mokomo does need data transfer but i need a pure power supply with multiple USB 2 ports, no data transfer needed! I don’t want to hook up the power supply to a computer, i just want a supply that delivers “clean” power over USB 2 ports.
I’m no electrican, but it seems like the only issue is the grounding? I’ve found devices like the ME-USB Iso Hub - Meilhaus Electronic which may be able to deliver “clean” power, but they just do not deliver enough ampere for devices like the 1010music Blackbox or other devices connected via a Birdcord. The ME-USB only delivers up to 700 mA on each port.
This would be great. Technically, it should be simple — a DC power supply, n-way isolation and noise filtering, and then n separate USB power drivers. I’d grab a few, especially if it supported PD for higher output devices.
Yes, seems like. There are devices like the USB 3.0 SuperSpeed Isolator 5kV from Intona which may work, but they are very expensive and also only deliver 2A.
What I don’t get is that if one of these plugs is about $4 and you don’t need all the bits, how hard is it to make a combined 4 port version with independent routes to a single mains plug except through 4 individual transformer circuits as you have in each $4 plug - should be less than 4 x $4
I don’t think so, but I wonder if a DI-box between the two USB devices work to remove the noise?
Like so:
multi port USB power supply
______________________________________________________________
⇑ ⇑
power power
⇓ ⇓
| USB device | ⇐ audio ⇒ | DI-box | ⇐ audio ⇒ | USB device |
Yes. But it can get rather absurd considering the size of a “traditional” DI box. Using multiple power supplies would have a smaller footprint and is 100% noise free. The best I could find so far is this little guy:
It does a great job in reducing noise. However, there are two side effects I discovered in my tests:
The phase of the signal gets inverted. I don’t know enough about this matter to say whether this is an issue or not.
The signal will lose some level in the very low-end (mostly at 40hz and lower) and there are some very minor changes of the level in the high end. With other words: there’s a little bit of distortion. But for me, this is totally acceptable. I usually do a cut around 50hz in my mix anyway.
Thank you very much, i’ll take a look at it. I was thinking about the Behringer HD400, it should be more or less the same but with 6.3 mm and stereo/two channels.
Yeah, I’ve used a bunch of those. Haven’t seen the phase reverse thing, but I’m guessing that’s device to device difference. QC isn’t great on the ones I’ve gotten — at least a 10% failure rate. Then again, they’re cheaper (and smaller) than a pile of Radial SB6s…
