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Live with A Hum vs. Buy An Outboard Phono Stage

It appears that I have an airborne hum that I can't seem to track down. I've done all the usual things (use cheater plugs, shorted ICs, etc.). Now, I am wondering if I should just ditch the whole effort, and buy an outboard phono amp, ala Bellari, Creek, and such. The turntable I have won't set the world on fire, but it does a more than adequate job if given the chance.

So, opinions please. Is it worth getting a phono stage, and plugging it into a dead-silent input, or will it suffer from the same thing?
licoricepizza

Showing 3 responses by mapman

mapman's avatar
mapman
21,856 posts
 
Have you tried physically moving the pre-amp with the phono stage around to see if the hum level changes with location?

If so, it is inductance hum from some nearby power transformer, possibly in power amp or other component(s) or other external source.

If you haven't already, try this first to determine if that is the problem. If so, switching to an external phono stage is not necessarily the solution. Addition shielding and/or relocation of components for better separation is.
mapman's avatar
mapman
21,856 posts
 
You may have a different problem yet this site provides some potentially useful shielding and measurement solutions.

http://www.lessemf.com/mag-shld.html
mapman's avatar
mapman
21,856 posts
 
" If I turn off the amp, but leave the preamp powered up, there doesn't seem to a problem."

Well, you need the power amp with accompanying hum on to play, don't you?

Sounds like the transformers in the power amp is the cause of teh inductance hum in the phono-pre....same problem I had.

Try separating them further apart physically and see if that helps. if your IC is too short, use a cheap longer one temporarily just as a test to see if it helps. If it does, get a longer good IC to your liking and keep them apart.
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