Modartt user forum - USB 2 vs 3

Re: USB 2 vs 3

2013-02-28T14:50:13Z

Luc Henrion wrote:

So,you too, you believed that USB 3 was 100% "backward compatible" with USB 2? WRONG! COMPLETELY WRONG!
First, many USB 2 soundcards will not work on USB 3: my MOTU 896 MK III "Hybrid" is not recognized at all, and my Focusrite Scarlett 18i6 gives me a splendid "BSOD". Great.
But the worst is yet to come: USB 2 provides a maximum load of 500 mA. USB 3 should provide 900 mA. Morality? If you did not pay attention, you connect an external USB 3 "self-powered" hard drive on a USB 2 port and ... or it is not recognized (not enough power) and you're lucky. Either it is recognized and gently starts to fry your USB port 2. Cost: a new motherboard, a CPU, memory and PSU. + a serious headache and a few days "off". Thank you.
Take care ...

http://www.focusrite.com/answerbase/en/...hp?id=1157

Re: USB 2 vs 3

2013-02-28T14:46:41Z

Luc Henrion wrote:

So,you too, you believed that USB 3 was 100% "backward compatible" with USB 2? WRONG! COMPLETELY WRONG!
First, many USB 2 soundcards will not work on USB 3: my MOTU 896 MK III "Hybrid" is not recognized at all, and my Focusrite Scarlett 18i6 gives me a splendid "BSOD". Great.
But the worst is yet to come: USB 2 provides a maximum load of 500 mA. USB 3 should provide 900 mA. Morality? If you did not pay attention, you connect an external USB 3 "self-powered" hard drive on a USB 2 port and ... or it is not recognized (not enough power) and you're lucky. Either it is recognized and gently starts to fry your USB port 2. Cost: a new motherboard, a CPU, memory and PSU. + a serious headache and a few days "off". Thank you.
Take care ...

I believe Focusrite has a firmware update to fix this issue. Check their website!

Re: USB 2 vs 3

2013-02-13T07:30:30Z

Another exeprience from another user (& very good pianist btw): plugging a "self-powered" USB3 drive into his PC USB2 port results in instant PC shutdown. Nice one.
He found a simple and clever solution however: he just bought a powered (of course!) USB3 hub and inserted it between the drive and the PC. Problem solved.

Re: USB 2 vs 3

2013-02-12T08:23:17Z

I'm not a professional on the PC side but I'm an audio professional and beta-tester for the likes of Soundscape /SSL since day one (1994). I have some experience about computer music. I had a contact with MOTU via e-mail and they admitted themselves that USB3 was not compatible - yet, of course - with their USB audio interfaces. Same for Focusrite. In the meantime, I still have USB2 ports on the same laptops so, no problem.
Nothing to do with any OS or Mac vs PC or whatever. And regarding the power (or lack thereof) it's in the specs of USB. I documented myself before writing this post. And I think it is worth to just say: "be careful".

If you "google" a little bit, you'll to find this:

http://en.wikipedia.org/wiki/Universal_Serial_Bus#Power

Power

The USB 1.x and 2.0 specifications provide a 5 V supply on a single wire from which connected USB devices may draw power. The specification provides for no more than 5.25 V and no less than 4.75 V (5 V±5%) between the positive and negative bus power lines. For USB 3.0, the voltage supplied by low-powered hub ports is 4.45–5.25 V.[47]

A unit load is defined as 100 mA in USB 2.0, and 150 mA in USB 3.0. A device may draw a maximum of 5 unit loads (500 mA) from a port in USB 2.0; 6 (900 mA) in USB 3.0. There are two types of devices: low-power and high-power. A low-power device draws at most 1 unit load, with minimum operating voltage of 4.4 V in USB 2.0, and 4 V in USB 3.0. A high-power device draws at most the maximum number of unit loads permitted by the standard. Every device functions initially as low-power but the device may request high-power and will get it if the power is available on the providing bus.[48]

Some devices, such as high-speed external disk drives, require more than 500 mA of current[49] and therefore may have power issues if powered from just one USB 2.0 port: erratic function, failure to function, or overloading/damaging the port. Such devices may come with an external power source or a Y-shaped cable that has two USB connectors (one for power+data, the other for power only) to be plugged into a computer. With such a cable, a device can draw power from two USB ports simultaneously.[50]

Re: USB 2 vs 3

2013-02-11T09:37:25Z

Yeah, that whole "oh well you need the right Firewire chipset" thing was a load of old baloney, if you ask me. It was more a case of manufacturers not testing their drivers properly and then palming us off with "mmm, Micro$oft, baaaaad" nonsense.
Evem RME's firewire driver for my soundcard BlueScreened regularly.

Re: USB 2 vs 3

2013-02-11T07:47:51Z

What did I wrote? "many USB 2 soundcards will not work on USB 3", OK? I didn't say "all". I just gave two examples. BTW, MOTU is aware of the problem, and "they are working on it". Focusrite also.
As for the OS, it's Win 7/64. Tested on two different laptops with built-in USB 3 ports.
I know RME did their home work. Fine. But I think you should care about it and not take compatibility for granted, that's all. USB 3 is just "physically" retro-compatible with USB 2. And even then... only up to a point: power. Think about it. Twice, before you burn your MOBO like I did.
I'll just repeat: take care.

Answering to myself: it reminds me furiously about Firewire compatibility some years ago... You bought a PC with a built-in Firewire interface to connect a sound card. And then you're been told that the Firewire chipset had to be this or this brand. And it DIDN'T work with another. And, better still: for this sound card (Yamaha MLan, e.g.) you needed a "TI" chipset", while you couldn't use it for a Presonsus. And vice-versa !!!
I'll never repeat it enough: never take compatibility for granted.

Re: USB 2 vs 3

2013-02-10T16:12:49Z

My RME soundcard works absolutely fine plugged in to a USB 3 port. Just saying...

USB 2 vs 3

2013-02-10T09:45:41Z

So,you too, you believed that USB 3 was 100% "backward compatible" with USB 2? WRONG! COMPLETELY WRONG!
First, many USB 2 soundcards will not work on USB 3: my MOTU 896 MK III "Hybrid" is not recognized at all, and my Focusrite Scarlett 18i6 gives me a splendid "BSOD". Great.
But the worst is yet to come: USB 2 provides a maximum load of 500 mA. USB 3 should provide 900 mA. Morality? If you did not pay attention, you connect an external USB 3 "self-powered" hard drive on a USB 2 port and ... or it is not recognized (not enough power) and you're lucky. Either it is recognized and gently starts to fry your USB port 2. Cost: a new motherboard, a CPU, memory and PSU. + a serious headache and a few days "off". Thank you.

Take care ...