Humming/Buzzing from Pro-Ject Speed Box II....

hey everyone... hopefully you can give me some insight as to the cause of my problem.
my system is comprised of a pro-ject Xpression III turntable, pro-ject preamp, pro-ject speedbox and peachtree nova amp. everything sounded lovely and worked great until i added the speedbox and now there is a hum as soon as the aux input is engaged... i.e. the needle doesn't have to be down. it's really annoying. i disconnected and reconnected everything but no dice. i moved the pre and speedbox further away from the amp turntable, no dice. any help/suggestions? thanks a lot.
What cartridge you're using?
Speedbox might have too much gain. Check also if the cartridge clips are properly connected. Check the ground connection if applied.
I realy don't know what you've been using before as your phono preamp if applies.
using the stock sumiko cartridge. it's a sumiko oyster. all connections and everything are properly in place. when i remove the speed box and run just the phono box it works fine without hum. only when the speed box is in the mix. if i have to remove it from the pipeline it's not the end of the world but i like the convenience it provides because i do listen to quite a few 45's.
Make sure that you don't keep speedbox next to cartridge. Try to move it as far as possible from sound pick up.
it's as far away as the cord will go...
if it's still on warranty, you can replace it. they might have ground path problems.