Ground loop hum
Thanx for the suggestions, guys, definitely worth trying. I guess there's more that can be done with chopsticks than just eating sushi. For the heck of it, I've got a Linn Sondek with/Valhalla & an Itok arm. Just replaced the cartridge with a Dynavector high-output MC - very fluid & musical when you ignore the hum. |
Melodious, To rid my tube system of hum (just so I could crank it to full gain to hear tube hiss with no stylus in the groove), I had to resort to grounding my tonearm separately to the preamp and then run a second wire from the 'table to the same spot. It worked the best for me to ground it right at the bearing in my old system. I was getting somewhere - the final step was to ground the preamp to my all metal stand! At high gain, there was a hum that would disappear when I touched the preamp and rack at the same time, thankfully no jolt or electrical buzz in the fingers. My system worked best grounded only at the preamp. Todd |
I noticed an interesting statement you made: This hum is volume-dependent and not insignificant, and is present even with nothing connected to the phono input on the back of the pre-amp.This says that your turntable is not the problem (yet!), although the above advice is quite correct about ground loops in a phono stage and how *hard* they are to fix. You must be right about the hum in the house power. In my fog, I remember something about terminating the phono input with a suitable (50K? ohm) input load before testing for hum and noise. I don't know about your VTL 2.5 pre-amp. There are folks out there who build moving coil (MC) pre-amps for fun and they may have more details for you. Once the turntable is hooked up, the potential for new ground loops exists. Check out the post: impedance mismatched ? |
