paging scott to thread...

he had an issue with this and required some outside piece of gear to make the output level work or some shit.

it's the thread about the oscilloscope.

dugstar wrote:

japmn wrote:Just put a 57 on the laptop speaker and call it a night.
You could do stereo if you want I guess.

ha! sold! worst thing is? i have actually done this before!!!!! many moons ago, somebody's internal sound card blew up. how we laughed.

Actually, if the internal sound card didn't work, then there would be no way for sound to come out of the speakers. Cause the speakers get their signal from, you guessed it, the internal sound card.

that damned fly wrote:paging scott to thread...

he had an issue with this and required some outside piece of gear to make the output level work or some shit.

it's the thread about the oscilloscope.

I ended up trying a 1:1 isolation transformer that I had lying around inside one of my first audio-gear projects, a phantom power box I built when I was in college. Then I went a step further and bought a tone generator so I didn't have to use the computer anymore. The issue there was more about impedance mismatching, with the output on my laptop having some kinda auto-impedance-sensing thing or another.

Big John wrote:This is not a problem if you are using a external audio box like a firepod.

Oh, but it is. If the external sound box gets its power from the computer's USB bus, for example. If the external box has its own power supply, that might do the trick. But my USB (external) sound card is what I was using when I ran into the problem fly mentioned above. And a couple different external USB sound boxes are what hipped me to this phenomenon in the first place. The solution we always used was to just run the computer off battery power while tracking or mixing. Battery power usually gets you a good 2 or 3 hours, which was always enough for tracking songs.




An easy solution to your problem is to have your DJ's do the normal thing and use iPods instead of laptops. Problem solved. Long battery life and whatnot. Plug them in even.

Another easy solution is to buy extra batteries for the laptops, and swap out the batteries in one laptop while the other is in use.

Then there's always building (or buying) a non-switching power supply as described above.

Probably not a great solution, but better than nothing, would be to rely on the DJ's to unplug before they're playing music, and as soon as the other guy/ other laptop is up, plug their laptop back in to get it charging back up. If they have enough time between when they're up and the other guy's up, switching the laptop into standby while it's charging will make it charge a little faster.


I hope you get it squared away in time. Laptop power supply noise is really fricking annoying. It drove me nuts until I realized you just have to run off batteries and charge that shit up every break you get. Too bad if you can't do that here.



Use iPods.

scott wrote:I ended up trying a 1:1 isolation transformer

This or using a balanced connection and lifted the earth should usually work for these problems. All you are doing is isolating the earths from each other, so for the case of an XLR cable, you would lift pin 1 at one end only.

maybe a UPS or running a power balancer would help?

http://www.furmansound.com/product.php? ... d=IT-20_II
http://www.furmansound.com/product.php? ... PS-PFP_PRO