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richswit
08-23-2012, 04:33 PM
So I'm using an m-audio fireport 2626. I have the output at 3 oclock.
Running 10 channels in SAC. Noise level is pretty high. Wondering if that is normal? It isn't any one channel, but when I mute the main output it is quiet. Is the noise from the 2626, SAC, or the laptop using a PCMCIA firewire card?

I bet I need a better computer.....
Using an older thinkpad.
Butch Bos
08-23-2012, 04:52 PM
Make sure you are using 24 bit not 16 bit
Makes a BIG difference

Butch
hkmorgan87
08-23-2012, 04:54 PM
I had the same problem when using a profire 2626. It was noisy when the gains were turned up that high. I usually had to set my gains that high to get a decent signal through the preamps. I never had that problem with an ada8k.
UpTilDawn
08-23-2012, 04:59 PM
So I'm using an m-audio fireport 2626. I have the output at 3 oclock.
Running 10 channels in SAC. Noise level is pretty high. Wondering if that is normal? It isn't any one channel, but when I mute the main output it is quiet. Is the noise from the 2626, SAC, or the laptop using a PCMCIA firewire card?

I bet I need a better computer.....
Using an older thinkpad.

Can't say as I've had any issues with noise using an old thinkpad and the pcmcia firewire card with rme multiface, or digiface and presonus digimax preamps. I'm inclined to think the problem might NOT be the old thinkpad, or the pcmcia adapter..... for what that's worth to you.
ssrsound
08-23-2012, 05:18 PM
I've seen that problem with laptops that have power bricks going bad. Try it on battery and see if that fixes it.
UpTilDawn
08-23-2012, 06:04 PM
I've seen that problem with laptops that have power bricks going bad. Try it on battery and see if that fixes it.

Oh, for sure! I didn't even think to mention that...

Nasty noises! :eek:

I added an Ebtech Hum eliminator http://www.ebtechaudio.com/humxdes.html
that goes between the power cable and wall outlet to my thinkpad over a year ago (and forgot all about it!).

It very effectively reduces that horrible noise to nearly inaudible at normal volume settings, although you can hear that there is still noise at the audio output by turning an amp up really loud to hear it.

None of that noise associated with the laptop power has gotten into any of the recorded tracks I've made in SAW running off of SAC, by the way.
905shmick
08-23-2012, 06:21 PM
Oh, for sure! I didn't even think to mention that...

Nasty noises! :eek:

I added an Ebtech Hum eliminator http://www.ebtechaudio.com/humxdes.html
that goes between the power cable and wall outlet to my thinkpad over a year ago (and forgot all about it!).

It very effectively reduces that horrible noise to nearly inaudible at normal volume settings, although you can hear that there is still noise at the audio output by turning an amp up really loud to hear it.

None of that noise associated with the laptop power has gotten into any of the recorded tracks I've made in SAW running off of SAC, by the way.

Ever wondered why there's no "UL" rating on that Hum X device? I'd be more inclined to just lift the ground than use the diode trickery inside of that thing. At least you know what you're getting into with the ground lift.
richswit
08-23-2012, 06:58 PM
I've seen that problem with laptops that have power bricks going bad. Try it on battery and see if that fixes it.

OH OH,,,,, the battery side of this laptop doesn't work. (did I mention it was free)

I will try the 24 bit setting, too.

Mr. Schmick doesn't seem to be fond of the Hum eliminator, though that sounds like a possibility.


[edit] Oh my, running at 24bit made it much quieter. thanks...
905shmick
08-23-2012, 07:16 PM
OH OH,,,,, the battery side of this laptop doesn't work. (did I mention it was free)

I will try the 24 bit setting, too.

Mr. Schmick doesn't seem to be fond of the Hum eliminator, though that sounds like a possibility.


[edit] Oh my, running at 24bit made it much quieter. thanks...

Test the laptop by lifting the ground. If it helps, then the Hum X will also work as it's basically doing the same thing, but uses a pair of reversed diodes to put the ground back in place in the event of a problem. The problem with the Hum X is that the size of the diodes it actually needs to be effective are far too big and expensive and wouldn't fit inside of the Hum X unit.
richswit
08-23-2012, 07:27 PM
Test the laptop by lifting the ground. If it helps, then the Hum X will also work as it's basically doing the same thing, but uses a pair of reversed diodes to put the ground back in place in the event of a problem. The problem with the Hum X is that the size of the diodes it actually needs to be effective are far too big and expensive and wouldn't fit inside of the Hum X unit.

Keep in mind I'm just a musician, but the laptop doesn't have 3 prongs, only 2. How would I lift the ground on that?
905shmick
08-23-2012, 07:44 PM
Keep in mind I'm just a musician, but the laptop doesn't have 3 prongs, only 2. How would I lift the ground on that?

You don't as it has no ground to begin with!
richswit
08-23-2012, 07:47 PM
I knew that.....;)
UpTilDawn
08-23-2012, 07:48 PM
...The problem with the Hum X is that the size of the diodes it actually needs to be effective are far too big and expensive and wouldn't fit inside of the Hum X unit.

Interesting and good to know.
dasbin
08-23-2012, 08:06 PM
I've had many problems with the PSU on different laptops introducing 60Hz (or a harmonic) buzz into connected audio devices. On battery, the problem goes away. It is always on laptops that have ungrounded PSU's. I once tried a little experiment and tied an earth line to a metal housing screw on the outside of the laptop. Buzz went away.

Definitely some ground reference issues with those little switching power supplies.
RBIngraham
08-23-2012, 08:32 PM
I've had many problems with the PSU on different laptops introducing 60Hz (or a harmonic) buzz into connected audio devices. On battery, the problem goes away. It is always on laptops that have ungrounded PSU's. I once tried a little experiment and tied an earth line to a metal housing screw on the outside of the laptop. Buzz went away.

Definitely some ground reference issues with those little switching power supplies.


That's odd. I have almost always found the exact opposite. Whenever I run into a laptop with a power supply that DOES have a 3 prong (grounded) AC plug, that is when I usually DO have an issue. And it's rare that I have an issue with a power supply that isn't grounded.

Either way, let's face it. The cheap switching supplies that are used in all the laptops and tiny form factor computers are not designed to be analog audio friendly and netiehr is most of the circuitry inside the computer. I doubt much if any real thought is put into making really clean audio outputs by most of the manufacturers.

This is one more reason I avoid Dell crap if at all possible. They always have grounded supplies on their laptops.
Butch Bos
08-23-2012, 09:07 PM
Same here no noise with ungrounded laptops and almost always buzz with a ground

Butch
Mattseymour
08-24-2012, 02:42 AM
Is it something to do with the ground not being passed through to the laptop? Although I'd have thought that more likely to create ground loops.
airickess
08-24-2012, 06:40 AM
OH OH,,,,, the battery side of this laptop doesn't work. (did I mention it was free)
Time to spend a few dollars and get a better and newer laptop. I purchased a brand new Lenovo in July for $300 at Best Buy (not my first choice but it was an emergency replacement).
gdougherty
08-25-2012, 07:34 AM
If 24 bit solved it, then it might have been 16 bit plus dither and the high gain that was the problem. I played with the Profire on rme's totalmix vs an ADA and found the noise floor to be at least 10db lower than the ADA at all settings. While I occasionally noticed hiss with my ADA rig, my all Profire rig has been near silent.