Pre-amp's a hummin...

  • Thread starter Thread starter Shaky Tee
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Shaky Tee

Between being and nothing
So, I've given up on usb audio and bought a new soundcard for my laptop - a Digigram Vxpocket v2 pcmcia card. I've discovered that, for a regular, dynamic mic (i.e. my SM57), my old usb audio card makes a great, clean mic preamp for my Vxpocket analog input, however, when I use my ART MPstudio preamp, and my SE 1000 condenser mic, and press record on my trusty multitracking software, I get a discernable hum that goes higher when I turn up the output volume.

Any ideas what causes this and how I can get rid of this? Thanks.
 
Hi...I'm just following you around. :)

Maybe shielding or grounding? Internal or external...does it do it with either mic?
 
Ahh, the dreaded ART hum. I have the tube MP and, despite all the good recommendations from the forums, I think it is LOUSY. The thing is just way too noisy, it hums like mad no matter what I do. I have tried it in 3 or 4 different locations, I have tried power conditioning, I have tried better grounding, I have sent it in for service.... still very noisy. I would love to know if anyone knows of tweaks or fixes for the problem, because so far this thing is the most expensive paperweight I've ever owned.
 
I've read about a fair number of the Chinese condensors with grounding problems due to paint on areas that should be bare metal inside the mic (the paint preventing a good groud contact point).
 
I guess I just don't understand grounding. How do you "ground" something?
 
You tell your kid they can't go out. :D

Okay. It's just a connection that is often made automatically when hooking some components together. Sort of a common negative connection shared by these particular components. The round prong on an electrical wall plug is a good example of a ground connection. Occasionally the ‘automatic’ connection fails to touch whatever it’s supposed to touch (could be dirt, could be mechanical deformation, broken wire, etc.) and thus you have no ground connection. Laaronx has a point regarding the Art ‘hum’. That’s why I was wondering if it does it with either mics. Hope this helps. Try hooking up alternate components as sort of a process of elimination. Disregard email.
 
I think if you replace the cheap tube that comes with, that might solve half of your noise problems.
 
Good point Chessrock- So what happens if I put in a Groove Tube 12ax7? I guess I should quit asking and try to find the dang things- I know I left them around somewhere . . . - Harvey, would you or anyone in your "mod posse" like to tell us about modifying preamps next? (Perhaps you already did and someone needs to direct me to the thread.) Surely these Art MP's are good for something? Mine's noisy as sin.
 
Tommy Cram seems to know a lot about replacing tubes. I guess it's pretty simple; rip the old one out and put in a new one. He seems to have some good suggestions on the types to use as well, and so forth. Try to see if you can track him down.

I can't believe all the varying opinions on this thing. I must have totally lucked out on mine. It's quiet as a mouse and sounds nice. Probably just a fluke.
 
Thanks, all.

The Art MP doesn't have a grounding plug. I'm assuming that all that some of the banging it's gotten from having other wires, equipment, etc. it's gotten from being shoved down in my laptop bag may have caused something to snap.

Either that, or one of the connectors is dirty.

I was able to resolve some of the hum the other night when I ran it through my usb audio device (ANOTHER preamp) into the VxPocket, and used the output mixing levels to adjust accordingly.

I also read on the N-track forum how someone replaced the MP's resident tube with another one (I forget the brand, but I think it was $9.95 at Radio Shack or something) and the thing rocked.

If I can find the brand name of that tube he referred to, it'd be way kewl!

Oh, and Monty...

I can't use my email address in my profile here (yahoo email addys have been banned). If you sent me something, I probably didn't get it.

Here's my actual email addy:

bigstarlet@yahoo.com
 
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