[Kawai_man]

I have this usb to spdif converter which i really like because it sounds alot better than the optical out from my mac http://cgi.ebay.com/new-Xitel-Minidisc-MD-Port-DG2-sound-card-Optical-Cable-/320491475433?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item4a9ec7d1e9, I tried running it on a 5v battery to improve the sound but it didnt work.
 
Heres what I did
 
1.I stripped the insulation on part of the USB cable and stripped the shield then I cut the red and black wire
 
2. I connected the red and black cables that lead to the device to the battery, I made sure the positive negative where correct.
 
with the modified cable my computer doesnt read the device, when I go to select it its not there. I tried it with two different USB cables I modifed and I know for sure the battery is working.
 
 
 
Is there any way I can power this device with a battery and also have the computer read the device?

 

[Kawai_man]

anyone?

 

[Hybrys]

The DIY forums would probably warrant a better response and more help.
 
Good luck with your project.

 

[glt]

Gnd must also connect to the computer. You cut the power line, but you just "tap" to the gnd line.

 

[wuwhere]

Or you can buy one like this.
 
http://www.amazon.com/gp/customer-media/product-gallery/B0002UQALQ/ref=cm_ciu_pdp_images_0?ie=UTF8&index=0

 

[Kawai_man]

Quote:

Gnd must also connect to the computer. You cut the power line, but you just "tap" to the gnd line.

Ok I did it this way and it worked , thanks man.
 
 
I was hoping to isolate the ground as well,  I only know of two ways; usb cable with optocoulers ( expensive) or separate circuit that isolates ground. Is there any other way?
 
btw It made a nice improvement in the sound.

 

[leeperry]

GND is required for hotplug detection I think, and the dirty computer ground won't make it through the toslink cable anyway

 

[Kawai_man]

Quote:

GND is required for hotplug detection I think, and the dirty computer ground won't make it through the toslink cable anyway

Yeah but I think it still effects the sound output , just chaging to battery made a good improvment I think elimanating the dirty ground will improve it even further, anyways it would be interesting to see.

 

[leeperry]

oh sure, but it'll take some active filtering then...in that flavor: http://www.circuitsathome.com/products-page/usb-interfaces
 
your choice if it makes sense to buy it for a $10 toslink card, it will also increase jitter most likely

 

[Kawai_man]

Yeah thats the circuit I was talking about, I kind of want to avoid that buying that

. I guess Im looking for a solution I could easily do myself without any cost or maybe a small cost.  I wonder if there is there a way to trick the computer into detecting it?

 

[leeperry]

GND is used for hotplug detection, no GND = no connected device AFAIK.

 

[wuwhere]

 
Quote:

 
btw It made a nice improvement in the sound.

Can you describe the improvements? I was looking for a battery operated hub but it seems that there are none available except for that CyberPower unit which received crappy reviews.

 

[Kawai_man]

It made a very good improvment in the sound separation and soundstage, and the highs are more extended and a little more defined, the bass is also more defined and  a little less mushy.
 
 
 
I found the way that a USB detects a device is that there is a pull-up resistor that connects to the ground at the device, the computer detects this and then it allows data to be sent to the device,  Im wondering if this resistor is passive or active and I wonder if I can just attach a resistor or something to the ground an this would trick the computer?