[linux-audio-user] USB 1.1 soundcard

[Karsten Wiese]

Am Sonntag 14 November 2004 23:55 schrieb Christoph Eckert:
> 
> >  - It has 2 Mic-Ins with XLR and Phantompower all feed from
> > the USB-bus, no extra powersupply.
> 
> Isn't phantom power 48Volts?
> 
> I wonder that the device can get 48V from the USB bus. One 
> device is allowed to get a maximum of 500mAmpere from the 
> bus.
> 
> USB is 5V. This means, the card has to convert 5V to 48V and 
> would certainly need more than 5V/500mAmp. Maybe the phantom 
> power is only available in conjunction with an external power 
> supply?

Don't know, but a step up converter wouldn't need much power, if the 48V would only feed some µA.
I guess a phantom powered mic sucks less than 1mA, no?
Somebody knowing please tell us;-)

Karsten