Mac Mini G4 1.42 with Apogee Duet Firewire interface making noise

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Level 1

10 points

Mac Mini G4 1.42 with Apogee Duet Firewire interface making noise

I just bought an Apogee Duet firewire audio interface for my Mac Mini G4 and I'm getting what sounds like firewire bus noise?

The noise goes away if I plug it into my G4 powerbook.

Is this a known issue? Anyone else have this problem? Is there a fix for this?

I'm running a G4 Mac Mini 1.42, 1gb ram, OS X 10.4.11

Thank you!

8 core, Mac OS X (10.5)

Posted on May 23, 2008 12:05 AM

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Answer 1

Boece

Level 5

6,264 points

May 23, 2008 4:39 AM in response to Mike Patrick

Anything else plugged into the firewire chain?

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Answer 2

May 23, 2008 8:25 AM in response to Mike Patrick

Are you using the same speakers on each computer?

Is everything on the same ground plane? The noise may not show up on the 'book as it is isolated from ground unlike the mini.

This may help: Macintosh: Solutions for noise in the audio signal

Some drives do inject a bunch of noise via firewire into the audio chain. It is like a ground-loop, only you can't get rid of it. If the drive causes noise in the audio chain you must eliminate them.

Luck-

-DP

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Answer 3

Mike Patrick Author

Level 1

10 points

May 23, 2008 11:50 AM in response to Mike Patrick

Everything is plugged in the exact same. Same speakers, same everything. Just switched the firewire cable from one computer to the other..

I think I've narrowed it down to what seems like noise from the video card. As the noise modulates with changes to the screen.

I'm guessing that their isn't proper shielding. Or there is and my mini is just defective, as I can't seem to find anyone else with this problem after hours of searching.

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Answer 4

Mike Patrick Author

Level 1

10 points

May 26, 2008 7:58 PM in response to Mike Patrick

Just picked up the mini from the Apple store where they did a diagnostic on it. They said there isn't a problem with it.

I brought it back to the studio, and of course... the noise is still there.

Upon further analysis of the sound and the activity of the computer, it seems to make the noise when ever there is drive access.

I'm quickly coming to the conclusion that the Mac Mini G4 is NOT for use in a studio environment...at least with the Apogee Duet. So very sad.

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Answer 5

May 27, 2008 2:52 AM in response to Mike Patrick

It could be the FireWire cable.

Luck-

-DP

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Answer 6

Mike Patrick Author

Level 1

10 points

May 27, 2008 6:28 AM in response to DaddyPaycheck

I swapped out the firewire cable twice.. No difference..

And like I was saying, it works fine with my powerbook.

What are my options? Buy a new one? Buy a PC?

It's truly frustrating to spend a fair amount of money on products that don't work as advertised.

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Answer 7

AndyO

Level 6

17,064 points

May 27, 2008 6:45 AM in response to Mike Patrick

I'm not sure that it's entirely fair to say that these products don't work as advertised. It's understandable that you are frustrated with the noise and that it shouldn't be there, but there is always some risk of extraneous issues when mating devices from differing manufacturers, and spurious noises are not at all uncommon with FW and USB components.

I'm not sure you answered Boece's question about what other devices are connected, and indeed, if there are other devices hooked up to your system, how everything is connected together. That information would perhaps be somewhat helpful, certainly in as far as being able to tell if there are possible issues such as the matter of grounding which has been mentioned. Given this is the primary difference between the PB and mini, this seems like the natural place to start.

Bear in mind however that these sort of problems can be very difficult to thoroughly investigate and diagnose, as your own diagnosis that first it seemed related to the graphics card and then to disk activity tends to show. Hubs (both USb and FW) can play a significant role in noise and variable performance, as can other peripheral devices, even if only connected, not necessarily in active use.

The more information you can give about the system in its entirety (including UPS is you have one), the better!

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Answer 8

Mike Patrick Author

Level 1

10 points

May 27, 2008 4:43 PM in response to AndyO

I've removed all other connected devices. except LCD display, keybaord, and duet from the mini..

The duet is connect to the mixing desk, then to the amp, then to the monitors.

The studio actually doesn't have a ground...

I do not have a UPS, though thought about getting one...

The Apogee Duet is pretty much made for macs...as they don't support PCs with this unit.

http://www.apogeedigital.com/products/duet.php

The extremely frustrating part of all of this is that Apple is being completely helpless.

They couldn't even do a hardware test on a scope or anything to try to diagnose the problem. Only software tests, which haven't shown anything.

I'm just getting to my wits end...with little to no options other than buying a new apple or building a PC.

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Answer 9

May 27, 2008 4:47 PM in response to Mike Patrick

No ground is a likely culprit.

Are you sure one device does not have neutral and hot reversed?

Luck-

-DP

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Answer 10

Mike Patrick Author

Level 1

10 points

May 27, 2008 5:44 PM in response to DaddyPaycheck

Just ran a test with a grounded circuit. No change... I actually can't reverse any of the leads, as all the outlets will only accept the power cables in a singular way. And none of my audio cables reverse tip/sleeve.

I think i've exhausted all options on my side.

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Answer 11

May 28, 2008 2:52 AM in response to Mike Patrick

So have you eliminated the keyboard, mouse and monitor as culprits?

Luck-

-DP

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Answer 12

Mike Patrick Author

Level 1

10 points

May 28, 2008 11:28 AM in response to DaddyPaycheck

Yup, tried disconnected everything, including keyboard, mouse, LCD.. All but the power and the Duet... Still got noise...

And if I know you're next suggestion, try unplugging either the power or the Duet... I'm sure would be successful. 😉

I also tried bringing in my G5 Dual 2.5, and the Duet was silent, and I tried the powerbook again, and plugged it into the mains, and it was silent.

Now for the interesting part...

I went and bought a BRAND NEW Mac Mini, 1.8 core 2 duo...

Guess what? NOISE! Though different noise, but none the less, noise.

So I'm going to give Apogee a call and talk to them.

Either the Duet is not compatible with the Mac Mini or, this Duet is defective.

Or Apple didn't design the Mini's hardware to Firewire spec.

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