OPUS 20 second delay causing speaker "thump"

lloydy · 02-11-2006, 01:09 PM

I have my OPUS 120W PSU remotely turning on two amplifiers. The remote signal isn't given to the amps until 20 seconds after the PC has turned on. I would therefore assume there should be no "THUMP" sound as the speakers are/amps are turning on AFTER the PC. It is really loud and really annoying. Any ideas?

Thank you all in advance,

LLOYDY

netmgr · 02-11-2006, 08:08 PM

do you get the thump if its not plugged into the pc audio out?

lloydy · 02-11-2006, 09:59 PM

Good diagnosing tip. I haven't thought about trying that. I will try tomorrow and let you know (it's a bit late now - UK). This would at least then let me know whether its the onboard sound causing the thump or the amps turning on.

In either case, what do you think is the best solution? I suppose I could get an external sound card (was hoping I didn't have to). Are there any other options? And what if it is the amps?

I don't get the "thump" on computer switch off (like many people with a "thump" problem do) so this would lead me to believe it is the onboard sound.

Thanks for your help,

LLOYDY

netmgr · 02-11-2006, 11:41 PM

a problem often occurs due to ground loop isolation, caused generally by the ground connection of both devices, pc and amp not joined

what sort of pc is it, does it run on mains? dc converter?

lloydy · 02-12-2006, 03:48 PM

My PC uses an OPUS 120W power supply. The whole system is the (expensive!) OPUS one from mp3car.com's shop. Both my amp and PC are grounded at the same point with a very good quality ditribution block.

I've done everything properly this is why I'm wondering why I'm getting this problem.

LLOYDY

lloydy · 02-17-2006, 07:09 AM

I'm sure it is the soundcard. Even more annoying is the fact I've got a ground loop (alternator whine) and buying a ground loop isolator did nothing. Hopefully, a USB soundcard will sort all this out. Just have to wait until my funds are looking healthier!

LLOYDY

strohj · 02-17-2006, 01:01 PM

is the case grounded? that is usually the culprit for on board noise...

lloydy · 02-17-2006, 04:03 PM

Not directly I don't think. How would I go about doing this? I assumed the case was grounded through the power lines entering the PSU.

Do I need to attach a ground cable to a bold on the card to the car chassis?

LLOYDY

strohj · 02-18-2006, 09:03 AM

it depends on how the power supply is connected to the case... but yes.. I would connect a cable to the case on one of the motherboard standoffs.. and ground that to the chassis of the car...

While that might not completely fix it... it should make it significantly less of a issue

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