High Pitched Sound From My VPI Classic/Cambridge Phono Section

[James Edward]

I have a very high pitched sound that appears AFTER I play a record or two. When I first turn on the system and select the phono input, it is quiet. When I lift the tonearm at the end of the record, it sounds like a dentist's drill. I can modulate the sound a little by touching the tonearm wire.
I am using a Dynavector 10x5 cartridge, and a Cambridge 640P phono section. All interconnects are shielded.
The noise is the same with the CD player on or off.
Any suggestions appreciated...

[richidoo]

Good one, Mr Rubik.   

No tubes, right? Phono preamp and TT sharing safety ground, at least same circuit? Try disconnecting your phono ground wire, or moving it to another location, or tightening it. Experiment.

A cart will change sound after half hour of "warming up," maybe that has something to do with this.

That's all I got man, sorry.

[James Edward]

Rich,

I do have a tube preamp, and hybrid amplifier. But the only source affected is the TT.

I must hang my head in shame, though, about the ground. I will hook one up and see if it solves the problem. Although, I've heard grounding issues before, and they never sounded like this.

[richidoo]

I used to have problems with buzzy hum with my old Bellari tube phono preamp, it actually sounded better without the ground wire connected! It was a common problem for many owners of that pre. Long gone now, thank goodness. 

[James Edward]

The ground wire wasn't it, though it got rid of a hum heard only at full volume.
Proximity to other equipment wasn't it either...

I switched out the Cambridge 640P with a Rotel RQ-970, and the problem went away.
So, whatever interaction they had just wasn't good, or the Cambridge is defective.
Also, the turntable on/off switch does not THUMP through the speakers when using the Rotel.

Thanks for the response...

[richidoo]

Hey, glad you figured it out James.   

[mikecole]

Go to this thread on Steve Hoffman forums to read about a similar problem. The last post is probably the most relevant:

http://www.stevehoffman.tv/forums/showthread.php?t=188406&highlight=10x5+640p

Mike

[James Edward]

Mike,
If I could say it like they do on the Guiness commercial: "Brilliant!'
I had a nagging feeling it was something about my setup, but it
appears to be a known problem.
Thanks!

[mikecole]

No problem, James. The only reason I saw that thread was that I was looking for a new phono stage for my 10x5. I ended up with one from a small company called Vista Audio. It is their Phono-1 and it turned out to be a *very* nice phono stage.