Topic: Hum while using an Edirol UA-25 and Wavelab

[kingnerd]

I just got an Edirol UA-25 running into a laptop and recording with Wavelab and am haiving a minor problem.  I have tried my SP C4s and ADK TLs and both show the problem.  The problem is that there is a mid frequency hum that is constant.  Nothing I have done has got rid of the problem.  I am running a Dell Precision M60 Pentium M 2.1 with a gig of ram.  I have also tried it with Cakewalk with the same results.

Has anyone else been able to get rid of hum problems in the past?  I hope that it isn't an inherent problem with the laptop.

Thanks,

Adam

[dnsacks]

does the ua-25 have a headphone out?  If so, can you hear the hum on the ua-25 itself? 

Since the ua-25 is sending the laptop a digital signal, I'd be really surprised if the problem is with the laptop (especially if you hear the same hum on a cd burned from the laptop).

[kingnerd]

Yeah, with the direct monitor turned on it hums through the headphones.  When I record and then playback I hear the same hum.  I guess that I should try to burn it to CD to make sure that the hum still exists huh otherwise it could be a cheap headphone amp. 

Could it be noise coming down the power line of the USB cable?

[dnsacks]

it could be (noise from the power provided by the usb cable) -- try connecting the ua-25 to a different computer and see if it goes away.  I'm betting you have a defective ua-25 (and that the hum is not computer-specific)

[kingnerd]

Ok, now this is strange.  When I bought the Edirol UA-25 I also bought some ADK TL-MPs and some Studio Projects C4s.  I traced the hum down to one of the ADK mics and one of the Cardioid C4 caps.  I know, I know.  You are probably saying, "No freakin' way"

With the C4s I can run one and it sounds fine and then when I plug the other one into the same mic cable into the same channel on the UA-25 it has a hum like you can hear the ocean.  100% of the time it does this.  I can change the bad cap to the other body and it still has the noise and the good cap to the other body and it sounds fine.   I also switched out the mic cable and had the same exact results. 

Then the crazy part is that one of the ADK TL mics is also hosed.  When I plug it in it also has a loud hum.  When I switch through the polar patterns the front pickup just doesn't sound right.  With a Cardiod patern the front side is muted and the back picks up.  With a figure 8 the front sounds muted but the back picks up fine, and so on.  After being on phantom power for about 30 minutes the noise drops a little bit and the pickup patterns start to fill in.  The hum never goes away though.  The other mic sounds wonderful like a large diaphragm should.

I ordered both of these sets of mics from different individuals.  I used to work in a recording studio so I am not a complete idiot(I hope).  I didn't do anything strange with them.

My question is, how the hell could this have happened?  Is it just my bad luck?  Did they get damaged in shipping?  Is UPS using some type of scanning device that kills microhpones(Tinfoil hat)? 

Luckily I bought these from reputable dealers new so hopefully getting them fixed will be a painless process.

Any insight would also be greatly appreciated.

Oh yeah, one more thing.  I also bought a Presonus Dual TubePre, also from a reputable dealer new, and when I plugged it in for the first time smoke poured out the top and it made a crackling sound.  Needless to say its toast and on its way to the glue factory as we speak.  My luck has been horrible with electronics in the past month.

[dklein]

very weird indeed.  Is the hum still present when you run the laptop on batteries vs. plugged in?