Hi !
I have a usb soundcard that can work without the 5VDC from the pc bus (it has an external psu).
I have received finally
my new soldering tool 
So I would like to start to burn my fingers
I am wondering ... could a mic cable be a good base for a usb data only cable.
A two wire + shield part that can transfer the data -/+ usb signals.
Question:
1) which mic bulk cable could be ok for usb signal transfer ?
2) can the shield be connected only at one end ? which one ? Pc or soundcard ?
Thanks a lot for any advice.
I have a usb soundcard that can work without the 5VDC from the pc bus (it has an external psu).
I have received finally
my new soldering tool So I would like to start to burn my fingers
I am wondering ... could a mic cable be a good base for a usb data only cable.
A two wire + shield part that can transfer the data -/+ usb signals.
Question:
1) which mic bulk cable could be ok for usb signal transfer ?
2) can the shield be connected only at one end ? which one ? Pc or soundcard ?
Thanks a lot for any advice.
Attachments
Last edited:
Buying any USB cables is willy-nilly, and none that I know of that are easily available give any performance figures whatsoever.
In my experimentation different generic USB cables can indeed cause subjective differences.
So just what is good USB performance and by what measures ?.
Dan.
Last edited:
Correct characteristic impedance would be a start (a mic cable is unlikely to provide this). Sufficiently low series resistance (a mic cable will do this, but this is probably less important than correct impedance). If a cable says it is USB-compliant and the maker is not telling lies then it is good enough for audio.Max Headroom said:
Transmission of data. They either work perfectly or hardly at all, that's the nature of data transfer.
But surely mic cables are designed for carrying audio signals? That must be better than a USB cable meant for carrying just bits of data?
Yes mic cables are designed to carry audio, not data. Why do you think audio is easier to carry than data with ten times the bandwidth?
Does the data get thru? Then the cable works. Does a word file transfered over usb change? Then either does your audio.
"In my experimentation different generic USB cables can indeed cause subjective differences."
As usual, you slip in the "subjective" word there! Thus you conveniently exclude yourself from having to measure, justify or explain anything. So all further discourse is pointless. Just your opinion.
"So just what is good USB performance and by what measures ?"
It works! I can pull any cable from the spaghetti scramble in my cable box and it works: Audio, streamed TV, Gigs of data.
In the past I have had a few USB cables that gave trouble. I decided they were faulty and binned them. Not worth the trouble to disect them.
As usual, you slip in the "subjective" word there! Thus you conveniently exclude yourself from having to measure, justify or explain anything. So all further discourse is pointless. Just your opinion.
"So just what is good USB performance and by what measures ?"
It works! I can pull any cable from the spaghetti scramble in my cable box and it works: Audio, streamed TV, Gigs of data.
In the past I have had a few USB cables that gave trouble. I decided they were faulty and binned them. Not worth the trouble to disect them.
Conductors which are normally used for power should not be disconnected (or removed) as this may modify the characteristic impedance of the data conductors. Instead, the power conductors should be grounded or connected to whatever impedance best mimics the output of the power supply. I guess a power supply will be the best mimic of a power supply?
Without the ground connection the USB will probably be very unreliable or not work at all. Some ground connection is needed to keep the common mode levels within the allowed range.
If noise is an issue it should be solved in a different way, e.g. with digital isolators on an I2S bus if this is available. Not by removing the ground (shield) of the USB cable.
If noise is an issue it should be solved in a different way, e.g. with digital isolators on an I2S bus if this is available. Not by removing the ground (shield) of the USB cable.
I have a similar'ish USB isolator powered from a car battery.
IME it does provide useful improvement in sound with tighter/cleaner positioning of sound sources (L/R and depth imaging) and cleaner sound overall..ie removal of film of 'haze' over the whole sound.
For best results use a USB type/gender adaptor directly between the isolator and the DAC.
Dan.
IME it does provide useful improvement in sound with tighter/cleaner positioning of sound sources (L/R and depth imaging) and cleaner sound overall..ie removal of film of 'haze' over the whole sound.
For best results use a USB type/gender adaptor directly between the isolator and the DAC.
Dan.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.