Those USB cable for CAS purpose, what kind of cables are they ?

RE: Those USB cable for CAS purpose, what kind of cables are they ?, posted on February 15, 2017 at 12:19:32
Mike B. Audiophile Posts: 26352 Location: OR Joined: September 27, 1999 Contributor Since: September 1, 1999	I have built several that I think sound very good. One had three 32 gauge silver wires twisted in a tight configuration. DC power is by a 24 gauge copper wire with shield. I use carbon fiber flexible covering. The other uses a similar layout with the exception of 24 gauge silver plated wire in teflon I sourced from ebay. The cover and shielded 5 volt feed remain the same.

RE: Those USB cable for CAS purpose, what kind of cables are they ?, posted on February 15, 2017 at 19:46:40
akltam Audiophile Posts: 1057 Location: Hong Kong Joined: September 29, 2002	For the 'power line' of the cable, did you solder the shield to the USB plug on both side ? Did you connect the shield to the power ground of the cable ? Thanks. Alan

RE: Those USB cable for CAS purpose, what kind of cables are they ?, posted on February 15, 2017 at 21:48:30

fmak
Audiophile

Posts: 13158
Location: Kent
Joined: June 1, 2002

Impedance should be as close to 90R as possible, with good shielding. It is economic to buy high end Wireworld cables in 5 or 7m lengths, cut them up and form shorter (as short as 10 cm) cables using the best gold plated plugs.

Take care to strip the cables and dress them correctly relative to the connector positions.

You will be surprised by the effects of cable length and whether which end is ties to Ground.

did you solder the shield to the USB plug on both side , posted on February 16, 2017 at 04:02:19
fmak Audiophile Posts: 13158 Location: Kent Joined: June 1, 2002	try send side, receive side and both. They sound different

I have not started yet. , posted on February 16, 2017 at 05:47:14
akltam Audiophile Posts: 1057 Location: Hong Kong Joined: September 29, 2002	I am just planning for these small fun projects. I will start from connect the shield on the 'Send' side first. I will update when I start these experiment.

RE: Those USB cable for CAS purpose, what kind of cables are they ?, posted on February 16, 2017 at 12:46:49

Duster
Manufacturer

Posts: 17117
Location: Pacific Northwest
Joined: August 25, 2002

USB cable specs involve a characteristic impedance range of 90 ohms � 15% (76.5-103.5 ohm). This tolerance is a bit tighter than the AES/EBU acceptable digital interface involving a generous 110 ohm � 20% range (88-132 ohm), but still allows plenty of wiggle room in terms of acceptable tolerance for a DIY build. If you only require a short length 0.5 meter USB cable, I'll be glad to share a built-from-scratch DIY cable build that should perform well as a home-brew USB cable.

This USB cable is what I am after, posted on February 17, 2017 at 06:06:58

akltam
Audiophile

Posts: 1057
Location: Hong Kong
Joined: September 29, 2002

Just find this interesting USB cable, the power line is from a separate cable so that you can supply power from a separate source to your USB Dac. And you can get a small Linear power supply for this purpose.

As the power line is separated, in theory there should be very very little interferance to the data line. So if your USB dac power its USB interface, you can leave the power line not-connected.

http://www.ebay.com/itm/201268922394?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

little interferance to the data line, posted on February 18, 2017 at 07:59:49
fmak Audiophile Posts: 13158 Location: Kent Joined: June 1, 2002	How the cables are dressed at the plug ends matter and this is the difficulty in soldering usb cables to unsympathetic contact layouts. I have just bought the cable you posted. The difficulty in using these cables lies in their stiffness!

And it might just be what I'm after . . . , posted on February 18, 2017 at 09:30:15
Ryelands Audiophile Posts: 1867 Location: Scotland Joined: January 9, 2009	Many thanks for the link. Can you or anyone else by any chance tell me if the Gnd line is connected in both the USB-A plugs? Obviously, it should be but I've seen some recommend not connecting Gnd on the data line in configs such as this. I wrote to the seller to check but haven't (as yet) had a reply. TIA D

RE: little interferance to the data line, posted on February 18, 2017 at 20:22:07

akltam
Audiophile

Posts: 1057
Location: Hong Kong
Joined: September 29, 2002

Mine will arrive in a week time. Maybe you can report back when yours arrived.

I am very much looking forward for this cable to arrive.

Because of this cable, I have bought 2 different USB Linear power supply from Taobao to try out. These LPS cost about 30-50 USD. I also have high hope such setup will improve my USB dac.

RE: And it might just be what I'm after . . . , posted on February 18, 2017 at 20:23:50
akltam Audiophile Posts: 1057 Location: Hong Kong Joined: September 29, 2002	My cable will arrive in a week time. I will report back when I got mine. Alan

RE: And it might just [not] be what I'm after . . . , posted on February 20, 2017 at 03:17:36

Ryelands
Audiophile

Posts: 1867
Location: Scotland
Joined: January 9, 2009

I just heard back from the manufacturer - he does not connect the Gnd line to the data cable's Type-A connector.

HTH

Dave

Computer Audio Asylum

Those USB cable for CAS purpose, what kind of cables are they ?

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