I fixed it !!

[Ixnay]

You may have seen the fun-filled adventure of my humming turntable, which got deleted because

Well, I fixed it. How? By moving it and the preamp over to the other end of the room. Now it's quiet as a tomb.

So now I have to decide whether to leave it there (forty feet of cable) or step by step edge it closer until the noise is noticeable. In any case I'll still have to find out what's causing the disturbance and if I remove all the wiring from that corner and the noise is still there it's the cosmos and I'll just have to live with it.

Thanks to those who tried to be helpful!

 

[Mr. Widget]

Great news!

Sounds like either your original power outlet isn't properly grounded or more likely your original location had some electrical device that was inducing hum into your phono system. If you want to try to make it work without forty feet of cable you might try looking for that source of hum.

If you determine what is the source of the induced hum you should be able to rearrange your setup to avoid audible noise. A couple of feet is typically enough distance to avoid hum.

 

[DVDdoug]

If I remember and understood what you said, I'm 99% sure your tonearm isn't grounded.

40 ft. of line level signal shouldn't be a problem, but it could be for the cartridge signal, so it's good that you moved the preamp with it.

 

[Ixnay]

I used my Fluke meter to measure continuity between the tonearm tube and the ground spade at the end of the cable. They were indeed connected.

 

[Mr. Widget]

I used my Fluke meter to measure continuity between the tonearm tube and the ground spade at the end of the cable. They were indeed connected.

But what was the resistance? Continuity alone does not mean you have a good ground.

 

[Ixnay]

Oh, please.

 

[restorer-john]

It's prbably that CT scan machine you have in the other room.

 

[suttondesign]

i used to have an ati amp which caused big headaches with surrounding equipment. i had to move them away from its fields.

 

[mhardy6647]

It's prbably that CT scan machine you have in the other room.

Or that CB (11 meter) radio runnin' heat (as we used to say... back in the day).

 

[restorer-john]

Oh, please.

He's right. Continuity beep means <40R typically on a Fluke 87 series. Good ground is down into tens/hundreds of milliohms. And you need to push some current through grounds to determine the actual resistance- a DMM can't do that.

 

[restorer-john]

Or that CB (11 meter) radio runnin' heat (as we used to say... back in the day).

Does anyone still use CB over there? It's all UHF here and boring.

I remember going up to the top of a local hill right near the ocean on a Saturday night in the early 1980s. Large water reserviors up there, lots of CB heads and we'd try to get 'skip' across the sea to New Zealand if the upper atmosphere conditions were right.

 

[DonR]

I used to hum a good tune when cranking up the old Victrola. Glad to see they still make buggy whips.

 

[mhardy6647]

Does anyone still use CB over there? It's all UHF here and boring.

I remember going up to the top of a local hill right near the ocean on a Saturday night in the early 1980s. Large water reserviors up there, lots of CB heads and we'd try to get 'skip' across the sea to New Zealand if the upper atmosphere conditions were right.

I honestly don't know. There are a couple of quite vintage (and relatively nice, for their time) AM/SSB radios down in the basement, but they haven't been used in... a long time.

 

[DonR]

I honestly don't know. There are a couple of quite vintage (and relatively nice, for their time) AM/SSB radios down in the basement, but they haven't been used in... a long time.

There must be a couple of Ham Heads on the forum.

 

[mhardy6647]

There must be a couple of Ham Heads on the forum.

I am sure there are... but they're mutually exclusive to anyone using the Citizens' Band -- especially nowadays.