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Hi Guys,

Having a very strange problem... Just got my UltraLite, and all is working great. I love it. My only issue (And don't believe it's with the UltraLite) is one of popping on my PA speakers...

Firstly, my setup is as follows:

FRONT:
Input 1 - Nothing

REAR:
Input 2 - Guitar lead into gutar
Inputs 3-7 - Nothing
Input 8 - Crappy cable to Mono out of Roland TD-20 V-Drums Kit (Planning on buying Stereo, SPDIF and Multicore soon)
Output 1/2 (Main) - Left and Right speakers - 2 x JBL EON 15 G2

Ok, so here's the problem... When I have the speakers on and the UltraLite on, I get a constant 'pop pop pop pop pop pop pop pop pop pop pop pop' sound. Sorta like when you get mobile phone interference but without the high pitched whirring sound (It's hard to describe?).

Here's my troubleshooting thus far:
- Turn off the MOTU, leave speakers on, noise stops.
- Play something through the MOTU, noise becomes hardly noticeable.
- Plug speakers direct into TD-20 and not via MOTU, no popping noise at all.
- Unplug speakers from MOTU and Plug headphones into the same output ports I was using for the speakers, No popping noise...
- Unplug speakers from MOTU and plug another set of speakers in their place, no noise...
- Plug speakers into TD-20 (No noise). Connect cable from any output to TD-20 Mix-In port, get a lower (Albeit noticeable) popping noise.
- Move speakers around, no change
- Change power points, no change

Ok so really scratching my head here... I'm thinking my speakers are ok because this problem doesn't happen when they are used as a standalone with the drums. Thinking the MOTU is ok as it doesn't make this noise when I plug in headphones or speakers there's no noise. Can't blame the TD-20 because it works well on its own and has low noise when I connect the MOTU to its mix-in.

So long story short, I want to know A) If I can stop the noise, B) If so, how and C) Can this noise damage my speakers? Or is it just an annoyance.

Thanks heaps, hope this hasn't been too confusing!!

........................................anyone? this is sending me insane.....

have you tried using external powersource, not the firewire connection for power

mh44 wrote:........................................anyone? this is sending me insane.....

I got exactly the same problem, it appeared after 3 weeks, the input levels on the display are shooting through the roof simultaneously with the pops

I work on an Imac, tested the Ultralite on various other systems and on a more recent Imac + a Quad-core Intel Mac Pro the problem didn't happen
on a few different older Dual-core PPC Macs the problem was apparent

I tried lots of things but it's driving me crazy

stand alone with the AC adapter it works fine wit no pops

I'm also having the popping noise issue with my ultralite (orginal) running on firewire buspower on Macbook Pro. It happens rarely, although it seems more frequently as of late, and I hear loud pops every few seconds and the meters on the display goes crazy. Here's a youtube video of someone's ultralite having the same issue:
http://www.youtube.com/watch?v=QrRYLpeKhWQ

This seems to be a common issue found all over the internet and it's strange that MOTU hasn't said or done anything about it. Updating the firmware to the latest hasn't changed anything.

What's weird in my case is that lately it's been happening only around 6am in the morning. That happens to be when my automated backup software SuperDuper is scheduled to start the backup process. I read on another forum someone describing this same issue and thinking it was connected to the background processes of their anti-virus software. So this might be a clue in troubleshooting what the real issue is.

Too bad though since I really like the ultralite otherwise but I'm not going to want to put up with being woken up when this happens nor give up backing up my computer.

I can now confirm that this problem can be triggered by background processes on the computer, in my case my backup software SuperDuper.

Just to update: So luckily my external hard drive has a usb port as well as fw800 and fw400. I stopped using the fw800 cable and instead connected it via usb. My problem has since disappeared and I can keep my scheduled drive backups again.