[Gitbags]

I've got a strange problem that I hoping someone else has encountered (and solved

). Whenever I plug a usb cable into my front bays it causes the digital signal from my M-audio 2496 to dropout for a second.

I've checked my IRQ and that seems fine I've also played with latencies and buffers, I've currently set the cards pci latency to 16 (was 32) and the cards buffer to 512 samples.

Could it be a ground issue? seeing as if the usb cable makes contact with the usb ports surround it has the same effect.

Any suggestions would be welcome, I've searched around but haven't found anything concrete.

If it helps my set up is as follows:

XP sp3> Foobar2000 0.9.5.6 asio> m-audio 2496> ca digital coaxial> ca dacmagic> novo
Cheers
Richard

 

[obobskivich]

shouldn't be a grounding issue, the front panel isn't connected to the M-Audio, correct? (I know that by stock specs, it can't be done, but I also know that modding it together isn't all that hard)

does connection to any USB port cause this? or only the front ones?

do you positively need the front USB ports? if not, I'd just disconnect them internally and see if the problem goes away, if so, just add a USB hub connected at the rear of the case, and you should be smooth sailing (yeah, this is my incredibly lazy man's solution to an incredibly stupid problem (and I mean stupid in the sense that it shouldn't be happening, but very clearly is, with no apparent logic))

 

[ShinyFalcon]

Does it constantly drop for 1 second or just once when you plug in a USB? ASIO4ALL (if you're using the software version and not the hardware) is sensitive to delays (like when installing programs or doing way too much at once, or perhaps in your case your compy taking its time to identify your device). Let's see what DPC Latency Checker says when you plug in whatever is causing your problem.

Is any of your devices AC powered (like something that needs to be plugged in to a wall)?

 

[HammerSandwich]

Task Manager, Processes, right click on Foobar, Set Priority, High.

 

[olblueyez]

Maybe an increase in the size of the Foobar Buffer would be appropriate.

 

[Gitbags]

obobskivich, your assumption is right the m-audio isn't connected to the front panel in any way. And it is only the front usb ports that cause it. I'll have a go at disconnecting them in a while as well as moving the card to a different pci slot. (the pci slot it's in is only a few mm from the usb headers on the motherboard).

HammerSandwich, its not a performance issue, seems to be a mechanical/ electrical one. powersupply doesn't seem at fault as the systems stable.

ShinyFalcon, unfortunately I'm having this problem regardless if anythings connected to the cable. No externally powered devices.

olblueyez, I've played round with the buffer, both on the card and foobar, so far hasn't seemed to help.

Cheers for all the help, it's not a major issue just a bloody irritating one.

 

[Gitbags]

Right I've disconnected the front usb ports but that hasn't solved it, I've just noticed that if I tap the dvd drives enclosure with anything metalic it has the same effect.

So, would I be right in thinking something isn't grounded? my power supply's (tagen 480) grounding cable is attached to the motherboard tray. should I try it else where?

Edit: Solved! I think

it seems I had screwed up my cases (akasa eclipse, in case anyone's interested) ground (it's been attached to the mobo tray for the past 4 years.) I've attached it directly to the chassis and the dropouts have reduced dramatically.


Edit 2: Well further messing about with the usb port has led me to the cause of the ground problem. The cable that connects the mobo to the front ports is wired wrong, so I'd connected it to the mobo in reverse thus messing up the ports ground.

Can't say I'm surprised, when I first got the case the power, reset, leds where wired up wrong on the case as well. Meaning the bloody thing wouldn't start up and the hdd light was the power led.

Cheers for all your suggestions. Makes me glad I decided to stop lurking and join up, even if it has cost me a bloody fortune so far!


Cheers
Richard