humming on all modules?

[spongetone]

I am noticing a humming on all of my three modules-two N72's and one A12. I have tried lifting the ground, unplugging all other things, etc-with no luck. The noise seems to lessen as I turn up the inputs to the modules-but that could just be that the noise is getting covered up by room noise, etc.

I have compaired these with my SM-Pro audio mic pres-and although their output is much lower-they seem to have no hum. Words of wisdom?



jamie Hoover

PS-I had a real tech check all of these before I ever used them with his scope-going through all the proper adjustments-and they all checked out fine...

[jmoore]

Is your chassis sitting near another device that could possibly be generating the interference? Try unracking the chassis and moving it to a different location and see if the noise goes away, gets better or gets worse.

[spongetone]

Good point, Yoda-but I did try-first thing-powering down and unplugging the other two sets of mic pre's in that same rack-with no luck. Would I really need to actually pull it out of the rack?

Jamie Hoover

[spongetone]

So is that all the involvement I get from you on this? There is nothing left to try?

[jmoore]

So is that all the involvement I get from you on this? There is nothing left to try?

Sorry. I don't hit this message board every day. You could be a little nicer.

I assume you've followed Tim's instructions to the T. Did you scrape away the paint on the face plate that surrounds all the holes? You'd be surprised what a difference that makes. Also, make sure the four screws that hold the faceplate on the chassis are screwed in TIGHT! Do you have the MuMetal shield separating your power supply from your preamps?

Anyone else?

[spongetone]

Hey!

Sorry to come off badly! I know you're busy fellers! I just love these things and want them to be top-shelf. I use them every day now-I've never had really good pre's before now.

They were all scraped pretty darn well when they came from you guys. I could check it again. I'll check the screws too. And yes-I do have the shields separating the power supply from the pre amps.

Thanks,

Jamie Hoover

[jmoore]

Definitely check it again. I had a pretty bad hum when I built my first module, and scraping away the paint and tightening the the faceplate to the rest of the chassis made it about 95% better. I have the older chassis with the steel plate covered with mu-metal shielding. It is my understanding that the newer chassis comes with a 1 piece mu-metal shield.

Anybody else have any advice for old spongetone?

[spongetone]

Hey!

Thanks-I shall try that and see. I'll get back if no luck-but hopefully that'll help. Thanks again-old Spongetone is pleased!



Jamie