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Electronics => Beginners => Topic started by: dog80 on October 16, 2013, 12:50:45 pm

Title: USB device not working with extension cable
Post by: dog80 on October 16, 2013, 12:50:45 pm
I have a cheap set of USB powered speakers and I wanted to integrate a USB sound card into the speakers so they can work with just the USB cable plugged in (no MIC IN cable).

Problem is that the sound card (it is this one: http://img.ebw.gr/9001/usb-sound-card.jpg (http://img.ebw.gr/9001/usb-sound-card.jpg)) doesn't seem to work with an extension cable attached. Even the LED won't turn on.

The voltage drop across the USB extension cable is insignificant, however I replaced it with a short piece of Cat5e cable (much thicker wires) soldered directly on the board.

Still no luck. Sometimes windows will pop a message that the device is not recognised. I tried the rear USB ports too and still nothing.

Any ideas?
Title: Re: USB device not working with extension cable
Post by: dog80 on October 16, 2013, 12:53:17 pm
Here's the wiring:

(http://i44.tinypic.com/icizbq.jpg)
Title: Re: USB device not working with extension cable
Post by: amyk on October 16, 2013, 12:55:42 pm
USB has a cable length limit. (http://en.wikipedia.org/wiki/USB#Cabling) 3m for low speed, 5m for full and high speed.
Title: Re: USB device not working with extension cable
Post by: fluxcapacitor on October 16, 2013, 12:59:10 pm
The red/black cable doesn`t look like its connected to anything ? .
Title: Re: USB device not working with extension cable
Post by: dog80 on October 16, 2013, 01:01:33 pm
Quote from: amyk on October 16, 2013, 12:55:42 pm
USB has a cable length limit. (http://en.wikipedia.org/wiki/USB#Cabling) 3m for low speed, 5m for full and high speed.

The length of USB cable I used was about 1 meter. The cat5 cable even less.
Title: Re: USB device not working with extension cable
Post by: Short Circuit on October 16, 2013, 02:01:16 pm
- USB cable pair needs to be twisted up to the connection point.
- It seems you are powering the speakers from the USB also; probably too much (inrush) current
Title: Re: USB device not working with extension cable
Post by: dog80 on October 16, 2013, 02:08:47 pm
I redid the solder joints and it seems to work for now....
Title: Re: USB device not working with extension cable
Post by: amyk on October 16, 2013, 08:59:20 pm
Quote from: Short Circuit on October 16, 2013, 02:01:16 pm
- USB cable pair needs to be twisted up to the connection point.
Very critical for high-speed, not so much for full and low.
Title: Re: USB device not working with extension cable
Post by: Monkeh on October 16, 2013, 10:33:18 pm
Quote from: amyk on October 16, 2013, 08:59:20 pm
Quote from: Short Circuit on October 16, 2013, 02:01:16 pm
- USB cable pair needs to be twisted up to the connection point.
Very critical for high-speed, not so much for full and low.

Still no excuse for not even trying to keep wires twisted up to termination.
Title: Re: USB device not working with extension cable
Post by: Kryoclasm on October 16, 2013, 11:45:27 pm
You might want to add an external regulated 5v source to power the speakers and just use the data lines of the usb. That way you will have plenty of power available.
Title: Re: USB device not working with extension cable
Post by: peter.mitchell on October 17, 2013, 04:46:00 am
Quote from: Kryoclasm on October 16, 2013, 11:45:27 pm
You might want to add an external regulated 5v source to power the speakers and just use the data lines of the usb. That way you will have plenty of power available.

Either that or whack in a buttload of capacitance. The speakers probably want a reasonably low impedance power supply.
Title: Re: USB device not working with extension cable
Post by: wraper on October 17, 2013, 06:49:01 am
Try to connect shield of the cable to the audio card where connector body was soldered.