noises on G2X out with usb cable connected

iPassenger · Posted: Wed Feb 07, 2007 10:41 am Post subject:

How do i ground computer and/or lift ground?

elektro80 · Posted: Wed Feb 07, 2007 10:46 am Post subject:

iPassenger · Posted: Wed Feb 07, 2007 10:53 am Post subject:

Nope, dunno where that came from.

Ok for the purposese of experimentations sake, removed the ground from a multi-plug which the pc is connected too, noise still there when usb is plugged in.

Sad

I think there is something wrong with the design of this machine, i have no noise at all when i disconnect the usb. Sad

elektro80 · Posted: Wed Feb 07, 2007 10:58 am Post subject:

Do you have a CRT or an LCD display? Is the USB cable running close to the CRT? Is the G2 or the desk or the audiointerface close to a CRT?

iPassenger · Posted: Wed Feb 07, 2007 11:03 am Post subject:

I have a 19inch LCD.

mosc · Posted: Wed Feb 07, 2007 11:06 am Post subject:

When you unplug the computer, does the noise go away?

elektro80 · Posted: Wed Feb 07, 2007 11:09 am Post subject:

iPassenger · Posted: Wed Feb 07, 2007 11:19 am Post subject:

No. Monitor not affecting on or off.

I have Firewire soundcard (Ozonic Keyboard)
USB external Harddrive (doesn't affect noise on or off)
Network card connected to Broadband modem (doesn't affect noise on or off)

Connected to Ozonic:
Mixing Desk
AMP (not switched on, doesn't affect noise either)

Connected to Desk:
Boss VF1 effex
Waldorf Pulse
Nord Modular G2

I actually disconnecting things fully, the only thing that affects the noise level is disconnecting nord usb cable.

Edit: Sample Removed

deknow · Posted: Wed Feb 07, 2007 11:25 am Post subject:

...i would try grounding the signal ground of the computer. run a wire from any metal connector shield of the computer (ie, the printer port screw terminal) to a known ground (metal center screw of a switchplate). do this with all power off (in case there is a problem with the computer powersupply). it's probably worth trying both with the computer plug grounded and lifted.

deknow

iPassenger · Posted: Wed Feb 07, 2007 11:30 am Post subject:

I think u may be right, i think perhaps my pc is not grounded at all, the casing at least.

what is a switchplate n bear in mind i live in a rented flat on the third floor.

iPassenger · Posted: Wed Feb 07, 2007 11:36 am Post subject:

breakthrough!! When I switched my keyboard off n listened for the noise from the desk it went away, plugged keyboard back on, noise returned.

So it is the loop created by the firewire and usb connections n the two devices. unplug either one and noise returns to normal levels.

deknow · Posted: Wed Feb 07, 2007 11:47 am Post subject:

...you should also chek to make sure that if you leave the power on on the kbd, but unplug the firewire cable, does the noise go away?

deknow

elektro80 · Posted: Wed Feb 07, 2007 11:52 am Post subject:

Isn´t the Ozonic either powered by the FW bus or a 12 volt external PSU?

M-Audio usually says : NEVER use the external PSU if the FW bus can deliver the juice. If the cable has that "big" FW plug in both ends, then it can power the Ozonic. Check the manual.

iPassenger · Posted: Wed Feb 07, 2007 11:58 am Post subject:

Ozonic is powered by FW as you say, altho i did try it off it's own power supply too but no change, altho switching the ozonic off but leaving it connected via firewire kills the noise coming thru the desk. So it would imply that it is the data and/or power transfer on usb nord or FW ozonic that is the problem.

Still no closer really.

iPassenger · Posted: Wed Feb 07, 2007 12:00 pm Post subject:

toying with the idea of moving the firewire card in pc away from the graphics card, it just seems odd that this problem would only show up when the usb on the nord was also connected, as i have other usb devices which have provided no such problems.

wot u reckon worth a go?

blue hell · Posted: Wed Feb 07, 2007 12:30 pm Post subject:

blue hell · Posted: Wed Feb 07, 2007 12:32 pm Post subject:

iPassenger · Posted: Wed Feb 07, 2007 12:43 pm Post subject:

when it all (pc n kit) boots up u can hear it communicating and negotiating with the gear etc.. that is just a recording of the residual noise when it is doing nothing in particular.

I tried moving the video card and firewire port card as far apart as poss but alas still no improvement.

Am quickly running out of ideas. (and patience, three whole evenings spent trying to sort it out now, when all i want to do is make music.!!!)

Aww well there is always tomorrow.

Very Happy

iPassenger · Posted: Wed Feb 07, 2007 2:21 pm Post subject:

Gonna try a friends USB soundcard to see if it is firewire n possibly my Ozonic or specifically USB and possibly the Nord.

Some quite trippy noises coming from my usb/firewire whatever, about +65dB.

EDIT: Sample Removed.

iPassenger · Posted: Thu Feb 08, 2007 2:37 am Post subject:

Contacted Clavia via phone today, they have advised that it is most likely a fault with the unit and I am currently trying to arrange a replacement with the suppliers.

iPassenger · Posted: Thu Feb 08, 2007 10:26 am Post subject:

I have arranged for the suppliers to pick up my G2, they have yet to source me a replacement so it looks like I will be without for a little while.
:.(

usedmanateesalesman · Joined: Feb 11, 2008 Posts: 16 Location: Houston

Please forgive me for thread resurrection, but I'm experiencing this same problem on a G2 I just picked up off of Ebay. Soundwise it's great, but when both the USB & and Audio are plugged in, it's pretty unusable. The noise is coming out the interface (a MOTU ultra lite), but it is NOT apparently on the audio outs of the G2. Rather it is coming back on the internal "computer audio" channel right out the mains. when I switch tasks, or open a web page (anything with some comp "work" going on) the sound reflects the work.

I've tested with both balanced and unbalanced cables. The computer is a macbook pro which is powering the audio IO over the firewire bus. Popping out the power connection makes no impact on the sound.

I was going to cut the ground on one end of a pair of unbalanced cables, but the only unbalanced I have left have the cheap plastic perma-molding so I don't have access to the wires.

Any ideas on this? The laptop does have the ground plug in the wall, but as I said I unplugged the cable altogether and it didn't make any difference. Similarly, plugging the G2 and the computer into the same power strip did not make a difference.

This isn't the normal 60hz hum that I'd use a groundlift plug for.. it is very frustrating though :/ Not sure if I have the will to mess with this if it is going to stay this way, please help if you can.. All input greatly appreciated. let me know what data I need to fill in to describe the situation. Obviously since this one has been in use since Aug 2006, sending it back to the suppliers for a replacement isn't an option.

usedmanateesalesman · Joined: Feb 11, 2008 Posts: 16 Location: Houston

I take back what I just said. The G2 sounds too good (when the USB is not plugged in) to just get rid of, nevermind the programming. I assert that I am about 99% sure if I find some unbalanced cables which actually give me access to the hardware (I don't have the stuff on me to make one), and I snip the shield on one end, that the loop will go away.

Who's with me!?

this is sparta! or something :/

intro post coming once I am comfortably set up. G1 mod is now sitting behind the rack, possibly becoming a for sale item.

blue hell · Posted: Mon Feb 18, 2008 2:44 pm Post subject:

Well yes, and besides it's not something Clavia will be able to fix I'm affraid ... both USB and audio "specify" ground loops ... I give you about 75% that cutting the audio grounds resolves the problem ... 10% that it get worse ...

These are tough problems and I'm glad that I don't have it anymore since I hooked up th G2s to another computer and started using the RME interface ... maybe a galvanic isolated unbalanced to balanced converter would do the trick.

usedmanateesalesman · Joined: Feb 11, 2008 Posts: 16 Location: Houston

I'm kind of thinking that it isn't that urgent. I mean, it isn't like I have to have the Editor running every time I use the synth ... and more importantly, considering I have two kids (one being not 2 months old yet), my audio levels are frequently restricted. If I turn down the mains on the Ultralite to a "reasonable" level, I can't hear the USB noise (or at least, let's say, when there is audio being produced, the s/n ratio is acceptable).

However, I will get a test unbalanced cable and snip the shield off sometime soon and report back whether it's in the 75% or 10% ... or the 15% where suddenly the thing programs itself!