Topic: Fireface 800 analogue outputs humming and buzzing

Hi there

I just hooked up my new FF800 and I'm getting a very loud buzzing hum through my monitors from all outputs including 1&2 (using TRS>XLR). The headphone output works fine with phones.

When I turn the FF800 off or unplug the jacks, the buzz stops.

Could my TRS-XLR cables be wired "wrong"? They work fine with my Firepod. Or perhaps it's a setting in the RME software? I couldn't see anything though.

Hope you can help.

Thanks

Re: Fireface 800 analogue outputs humming and buzzing

Hi,
Could be a groundloop, you can try to use another wallsocket for your FF power cable.


Regards,
Alex

-----------------------

Various ADK computers :-)

Re: Fireface 800 analogue outputs humming and buzzing

Hi Alex, thanks for your response. I'll try the ground lift switch on my monitors, although I am using the same wall socket as all my other gear and which is the exact same one as I had my firepod plugged into - never had any ground problems before.

Could it be a faulty unit?

4 (edited by martin_rawlins 2009-03-04 12:40:13)

Re: Fireface 800 analogue outputs humming and buzzing

OK so the ground lift did nothing, so I tried plugging my headphone amp into the Fireface's outputs. There was no noise at all, so I can eliminate a physical problem with the unit at least, I think.

But what does it mean? Is it confirmation of a ground loop between my active monitors and the FF800?

Re: Fireface 800 analogue outputs humming and buzzing

Im having a similar problem. In another post I read

"No, this is normal, believe it or not. The noise is introduced by the power supply itself. The power supply that the Fireface comes with is an isolated switch-mode power supply, which means that it is not connected to ground. When you connect the firewire cable you are effectively connecting your Fireface's ground to to your computer's ground via the Firewire cable, and any noise introduced by the power supply is quickly absorbed by your computer's ground."

Can someone explain this. When my FF800 is connected to the computer (whether the power is on or off or the power cable is plugged in or not) Its like I hear my computer "thinking" any movement of the mouse, anytime the hard drive is accessing data, I get this noise that sounds like buzzing in the rhythm of the old dial-up noise. Its awful, and worse when I open Sonar 8.3. If I disconnect the firewire cable -silence.

Also, where is this "bus power" switch I read about in another post?

Re: Fireface 800 analogue outputs humming and buzzing

martin_rawlins wrote:

OK so the ground lift did nothing, so I tried plugging my headphone amp into the Fireface's outputs. There was no noise at all, so I can eliminate a physical problem with the unit at least, I think.

But what does it mean? Is it confirmation of a ground loop between my active monitors and the FF800?

Hi,
Do you use balanced or unbalanced cables to your speakers; maybe you have to open a connector to see if there are 2 or 3 wires.


Regards,
Alex

-----------------------

Various ADK computers :-)

Re: Fireface 800 analogue outputs humming and buzzing

Hi, yes balanced TRS - XLR. I will try and get some different ones today.

Thanks Alex.

Re: Fireface 800 analogue outputs humming and buzzing

OK so it was the wiring configuration on the TRS to XLR cables. I had some made up as follows:

XLR Pin 1 = Screen
XLR Pin 2 = Tip
XLR Pin 3 = Ring

and it solved the problem. My other cables were wired with pins 2 and 3 the opposite way around.

Thanks for all your help.

9 (edited by quoricsant 2009-03-06 09:08:04)

Re: Fireface 800 analogue outputs humming and buzzing

drobinsondn wrote:

Can someone explain this. When my FF800 is connected to the computer (whether the power is on or off or the power cable is plugged in or not) Its like I hear my computer "thinking" any movement of the mouse, anytime the hard drive is accessing data, I get this noise that sounds like buzzing in the rhythm of the old dial-up noise. Its awful, and worse when I open Sonar 8.3. If I disconnect the firewire cable -silence.

Yes same thing happens to me sometimes I can hear EVERYTHING my pc does (I think I can even hear the processors!). Like a telephone operator in the 1920s.
Very annoying indeed.

Have not pinpointed the cause, though.
I suspect a ground problem..

10 (edited by DavidP 2009-03-06 14:47:31)

Re: Fireface 800 analogue outputs humming and buzzing

I finally got to hook up my FF400 for the first time yesterday. I got a similar symptom :

No noise with just the FF and the laptop. Excellent playback quality, even. (I'm using Reaper)

When I add my guitar processor (Axe-FX), and just connect its inputs to the master outputs in the matrix, I hear a loud whistling noise, which changes slightly with everything the PC does.
If I remove the Axe-FX inputs from the matrix, no noise anymore...
Note that I'm using an unbalanced connection between Axe-FX and FF400.
Axe-FX directely into the speakers does no noise, either.
Ground loop or feedback problem ?
I'll test lifting the ground from the Axe-FX tonight...

Any other suggestion or explaination ?

Cheers,

David

Re: Fireface 800 analogue outputs humming and buzzing

drobinsondn wrote:

Im having a similar problem. In another post I read

"No, this is normal, believe it or not. The noise is introduced by the power supply itself. The power supply that the Fireface comes with is an isolated switch-mode power supply, which means that it is not connected to ground. When you connect the firewire cable you are effectively connecting your Fireface's ground to to your computer's ground via the Firewire cable, and any noise introduced by the power supply is quickly absorbed by your computer's ground."

Can someone explain this. When my FF800 is connected to the computer (whether the power is on or off or the power cable is plugged in or not) Its like I hear my computer "thinking" any movement of the mouse, anytime the hard drive is accessing data, I get this noise that sounds like buzzing in the rhythm of the old dial-up noise. Its awful, and worse when I open Sonar 8.3. If I disconnect the firewire cable -silence.

Also, where is this "bus power" switch I read about in another post?

Hi,
Could you tell us where you read that(link)?
And can you give details about your setup, without that it's not easy to try and help you.
About the bus power switch, I don't think there is any on the FF800.


Regards,
Alex

-----------------------

Various ADK computers :-)

Re: Fireface 800 analogue outputs humming and buzzing

DavidP wrote:

I finally got to hook up my FF400 for the first time yesterday. I got a similar symptom :

No noise with just the FF and the laptop. Excellent playback quality, even. (I'm using Reaper)

When I add my guitar processor (Axe-FX), and just connect its inputs to the master outputs in the matrix, I hear a loud whistling noise, which changes slightly with everything the PC does.
If I remove the Axe-FX inputs from the matrix, no noise anymore...
Note that I'm using an unbalanced connection between Axe-FX and FF400.
Axe-FX directely into the speakers does no noise, either.
Ground loop or feedback problem ?
I'll test lifting the ground from the Axe-FX tonight...

Any other suggestion or explaination ?

Cheers,

David

So it was definitely a ground loop.
I just unplugged my laptop for its power adapter, running it on battery, and the noise was gone. Sound quality = excellent.
More experimentation is needed to find out how to eliminate the ground loop while running the PC on its power supply (my guitar processor can't be ground-lifted on its unbalanced outputs...)

Re: Fireface 800 analogue outputs humming and buzzing

Hi,
This could help http://www.audiomasterclass.com/arc.cfm … ent-got-it


Regards,
Alex

-----------------------

Various ADK computers :-)

Re: Fireface 800 analogue outputs humming and buzzing

DavidP wrote:

... I'll test lifting the ground from the Axe-FX tonight...

I have similar problem - can you tell me how you "lift the ground"?

Thanks ...

Re: Fireface 800 analogue outputs humming and buzzing

They sell ground lifters in music or electronic stores. An 'unsafe' way to lift the ground is to plug your three prong plug into a two prong adapter. That removes the ground. That is what I did and it totally removed the noise. I had no idea my keyboard was causing this noise because the noise changed when I moved the mouse or screen, so I thought it was a motherboard or pci card problem.