VPI Scout Hum


Hello, I have a new VPI Scout and I am getting a low hum. I worked through the whole chain and I believe I have isolated it to the TT. Basically if I disconnect the table from the phono input the system is quiet...no hum. When I plug the TT in the hum is there. I tried unplugging the tone arm plug from the RCA junction box and it just adds buzz to the hum, when I plug it back in the buzz goes away and the hum remains. If I unplug the motor the hum remains. Even if I detach and unplug the motor and put it on the other side of the house in a closet wrapped in lead the hum remains. I am guessing it is a grounding issue but the table is factory grounded under the chassis so to speak. I tried running a wire from the chassis to another ground and no change. The only thing I can think of is the cartridge. Is a hum possible from just the cartridge?? if so what could it be? non of the wires are crimped or pinched or broken everything looks perfect. By the way it is a Dynavector 10X5.

Thanks!
kozmonot
I listened to a record at my dealer's once on a VPI/Transfiguration/CJ/Soundsmith phono/Vandersteen system worth probably about $30,000 and the sound blew me away. But once the record ended the hum/hiss was equally shocking at the high volume level I was listening at. After that I simply assumed that hum/hiss is simply a part of the analog experience but usually doesn't get in the way of music that much. I certainly felt much better about my humble--in comparison--Scout/Soundsmith Aida cart and phono rig that was producing some hum/buzz when not playing.

That said, VPI recommends replacing the TT cables with the cheapest, well-shielded cables you can find, if there is excessive hum. I ran the Kimber Silverstreak initially from the tt to the phono stage and I replaced it with a pair of Radio Shack cables that were on sale for the whooping $1.30!!! And guess what? It actually decreased the hum! Son of the b...ch! I suggest you try that solution since it virtually costs nothing.
Check to see if your TT or phono stage IC's are near a power cord. That will give you a hum even with excellent cables. Move your RCA's or XLR's around a bit to see.
Some VPI's use unshielded cables from the back of the tone arm to the the interconnect box. If your cartridge is a high output, that means it is high impedance, and unsheilded wires are a big problem. (Not so with Low output MC;s - the low impedance system tends to inherently be insentive to AC fields) Also - Someone on this thread mentioned the possible use of UNSHIELDED RCA cables - NO - NO - NO. THeya re very correct. VERY WRONG to use such. You cannot use such for low level signals of ANY kind. Thats why cheap shielded cables helped.

SO.....

1) Get sheilded cables for your RCA's from table to Preamp if you are using flat unshielded cables.
2) Move ALL ac cables away from the rear of the VPI if the tone arm exit cable is unshileded (you can see colors instead of silver shield wire). IF YOU TOUCH THIS WIRE and the hum gets worse, THATS your problem. TO fix that:
3) Wind some VERY soft VERY THIN single strand copper wire (take it from an old AC cord or speaker wire)in a sort of tight spiral (with gaps) wrap around the UNSHIELDED tone arm wire with the loose, long end near the arm wire jack. THEN, do it again but wind the opposite direction. Again the free end should be near the jack. Twist the loose ends together. Connect them to the GROUND LUG on the VPI box. Of course run a ground from this lug to your preamp.

Hum gone.

Peter Ledermann/President/Soundsmith
Peter,
Thank you so much for your input! It's greatly appreciated. I hope you're healthy and feeling great.

I'm using your Aida MI cart in Ebony on my Scout with your MMP3 phono stage and I love it. I too experienced some hum, but it decreased after I replaced my Kimber Sliver Streak with a cheap, well-shielded interconnect from Radio Shack from the Scout to the phono preamp. (I'm running the Silver Streak from the phono to my main amp now.) One question I have to clarify: how do you tell if the tonearm wire is unshielded? If you see just silver, it means it's unshielded, and if it has colors, that's the shielding, right? It appears my Scout has a silver wire with a colored wires twisted together. Would the copper wire trick help with the hum further? Thank you.
If the lead out wire from the rear of the tone arm is twisted COLORED wires, its unsheilded. Then you need to do my trick with the copper wire to make it a bit shielded. If it is silver colored, it is shileded. Nothing to do. Our cartridges are six sided magnetic shielded, so they dont hum at all.

Bear in mind that cheap Radio Shack cables are likely NOT well shielded, so you may want to go for some reasonable cables. The STRESS here is on the word REASONABLE - Dont go nuts with cables. Good shileded cables are fine - leave some funds left to buy some shoes for the children with the money you save.

Your flat cable from your Soundsmith preamp can still creat some hum, so try routing it away from AC fields as you listen.... or replace it with shielded types.

You should NOT have any hum AT ALL with our cartridges if all is well with your cables....and the possible VPI mod.

Peter Ledermann/Soundsmith