JoshT Posted November 27, 2010 Share Posted November 27, 2010 When I use the USB out from the MacBook Air, I get terrible static for about 10 seconds each time I touch the touch pad. The static then suddenly disappears and all sounds fine. Sometimes the problem does not repeat itself after an hour or so of play time, but usually it happens each time I touch the touch pad. This does not happen when I stream to the AEx that is separately connected to my DAC by mini-Toslink to Toslink. The DAC is a Music Hall DAC25.3 and I am using a generic USB cable. Any thoughts on the source of the problem? I posted the same question over on the PC Audio forum at AA a week ago but received no responses. Josh Link to comment
PeterSt Posted November 27, 2010 Share Posted November 27, 2010 Josh, It's just a long shot ... but if your DAC is on USB as well (sorry I don't know), any chance of using a different USB port for either ? Although I never could proove any such "out of sync" thing, e.g. Chris has written about it sufficiently enough, so I guess it just can happen (on a Mac (only ??)) and then USB priorities would be "capable" of just mimicing this. Your suggested trial would be about using two USB ports not being on the same internal hub. But I wouldn't know (again) whether such a thing (more hubs) exist on your Mac. Btw, if all is "right", the time it takes to "reset" things will be the buffer size in use. Not that you can change that (I think). Despite all the vagueness, I hope this helps you. Peter Lush^3-e Lush^2 Blaxius^2.5 Ethernet^3 HDMI^2 XLR^2 XXHighEnd (developer) Phasure NOS1 24/768 Async USB DAC (manufacturer) Phasure Mach III Audio PC with Linear PSU (manufacturer) Orelino & Orelo MKII Speakers (designer/supplier) Link to comment
The Computer Audiophile Posted November 27, 2010 Share Posted November 27, 2010 Hi Josh - It may be related to this issue http://www.computeraudiophile.com/content/USB-Port-Not-USB-Port Founder of Audiophile Style | My Audio Systems Link to comment
Tipper Posted November 27, 2010 Share Posted November 27, 2010 Plug in an Ethernet cable that goes to a grounded router and see if that cures it. USB Dacs powered by USB seem to have grounding problems with some laptops which don’t have an earthed power supply. If that does cure it then adapt an Ethernet cable to ground only (no signal wires) Dedicated Mains Cond dis block. Custom Linux Voyage MPD server. HRT Music Streamer Pro, Linear mains powered ADUM Belkin Gold USB cable. TP Buffalo 11, Custom XLR interconnects/Belkin Silver Series RCA. Exposure 21RC Pre, Super 18 Power (recap & modified). Modded World Audio HD83 HP amp.Van de Hull hybrid air lock speaker cables. Custom 3 way Monitors,Volt 250 bass&ABR, Scanspeak 13M8621Mid & D2905/9300Hi. HD595 cans.[br]2)Quantum Elec based active system self built. Link to comment
JoshT Posted November 27, 2010 Author Share Posted November 27, 2010 This is last year's MacBook Air and it apparently has only one USB 2.0 port. There is another port that looks like a peripheral USB port (the "B" side?), but I think it's the DVI display port (whatever that is) based on looking at the specs page. I think the only way to use ethernet is to use a USB to ethernet adapter in the same port. I mostly stream to an Airport Express from my iMac anyway, and plan on getting a MacMini if I decide to go USB, so this isn't a big deal, but it's puzzling me. There are no drop outs from the USB, just about 5 to 10 seconds of bad static before everything clears up, and only after touching the touch pad. Josh Link to comment
The Computer Audiophile Posted November 27, 2010 Share Posted November 27, 2010 Hi Josh - Can you attach a screen shot of your USB details from the About This Mac section on your Air? I'm interested to see if anything stands out as a possible cause. If not, no worries :~) Founder of Audiophile Style | My Audio Systems Link to comment
The Computer Audiophile Posted November 28, 2010 Share Posted November 28, 2010 Hi Josh - One more thing. Do you get this static whether on battery or plugged in power? Founder of Audiophile Style | My Audio Systems Link to comment
JoshT Posted November 28, 2010 Author Share Posted November 28, 2010 Not sure how to do a screen shot! Here is some information. Is this what you're looking for? USB Bus: Host Controller Location: Built-in USB Host Controller Driver: AppleUSBOHCI PCI Device ID: 0x0aa5 PCI Revision ID: 0x00b1 PCI Vendor ID: 0x10de Bus Number: 0x04 Apple Internal Keyboard / Trackpad: Product ID: 0x0223 Vendor ID: 0x05ac (Apple Inc.) Version: 0.73 Speed: Up to 12 Mb/sec Manufacturer: Apple Inc. Location ID: 0x04600000 Current Available (mA): 500 Current Required (mA): 40 IR Receiver: Product ID: 0x8242 Vendor ID: 0x05ac (Apple Inc.) Version: 0.16 Speed: Up to 1.5 Mb/sec Manufacturer: Apple Computer, Inc. Location ID: 0x04500000 Current Available (mA): 500 Current Required (mA): 100 USB Bus: Host Controller Location: Built-in USB Host Controller Driver: AppleUSBOHCI PCI Device ID: 0x0aa7 PCI Revision ID: 0x00b1 PCI Vendor ID: 0x10de Bus Number: 0x06 BRCM2046 Hub: Product ID: 0x4500 Vendor ID: 0x0a5c (Broadcom Corp.) Version: 1.00 Speed: Up to 12 Mb/sec Manufacturer: Apple Inc. Location ID: 0x06100000 Current Available (mA): 500 Current Required (mA): 0 Bluetooth USB Host Controller: Product ID: 0x8216 Vendor ID: 0x05ac (Apple Inc.) Version: 1.80 Serial Number: 90840DF3EFAD Speed: Up to 12 Mb/sec Manufacturer: Apple Inc. Location ID: 0x06110000 Current Available (mA): 500 Current Required (mA): 0 USB High-Speed Bus: Host Controller Location: Built-in USB Host Controller Driver: AppleUSBEHCI PCI Device ID: 0x0aa6 PCI Revision ID: 0x00b1 PCI Vendor ID: 0x10de Bus Number: 0x24 Built-in iSight: Product ID: 0x8505 Vendor ID: 0x05ac (Apple Inc.) Version: 3.19 Serial Number: 8HA1504NE2DM3L00 Speed: Up to 480 Mb/sec Manufacturer: Apple Inc. Location ID: 0x24400000 Current Available (mA): 500 Current Required (mA): 500 Josh Link to comment
JoshT Posted November 28, 2010 Author Share Posted November 28, 2010 Hi Chris - it happens whether plugged in or running on the battery. Just double checked. Josh Link to comment
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