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My Dual turntable doubles as an AM receiver.

F

Fisten

New Member
I have an old 1229 Dual that had a frayed 2 foot (original) RCA cable. I replaced it with a new medium-priced RCA cable which is 3 times the length of the old cable. (about 6 foot) so it can connect directly with my receiver without using extensions.

Volume appears to be increased, and it does sound a little cleaner to my ear. However, it is also now picking up AM. It's proportional to the receiver's volume, and transmits even if I'm not playing a record. (Ie, when the receiver is turned to phono, and there is power to the turntable.)

The turntable is not grounded. I have tried those cheap Amazon ferrocores on the cables to no effect.

Are there any solutions I can try, and if not, can anyone recommend an approximately 6-foot cable that is shielded, and/or at least not prone to picking up the local radio station, that wont break the bank.
 
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Make sure when you're installing the ferrite beads you're doing it correctly, one near each end and the cable goes around as well as through.

You can shield the RCA cable by running it through a braided metal wire sheilding sleeve. Connect one end of it to a ground somewhere. Cheap and easy, they're available on Amazon.

EDIT: For some reason I read that you had extended the power cable. The 6 foot RCA cable is now an antenna and your problem. The sleeve I mention above will resolve the issue.
 
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Is there a way to do a search for the RCA cable in question to see if this is a common occurrence with the cable? Does it have RCA's at both ends or did you solder in the new cable? It doesn't seem to be an issue with length of cable, because you used the original cable before with extensions. I guess you could try adding the extensions to the new cable to see if it has any effects.
 
sound hound said:
Is there a way to do a search for the RCA cable in question to see if this is a common occurrence with the cable? Does it have RCA's at both ends or did you solder in the new cable? It doesn't seem to be an issue with length of cable, because you used the original cable before with extensions. I guess you could try adding the extensions to the new cable to see if it has any effects.
Click to expand...
https://www.amazon.com/dp/B00OYH6DCO?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1 It was just an average cable advertised as OFC (Which, looking at it, I doubt), and shielded....also doubtful...

I soldered it directly to the blades that insert into the corresponding part...call it a sheath.... tested all. good conductivity.

Good pickup with the extension: Correct, I had connected it with a good 4 feet of extension connects with no issues whatsoever. Seems the difference is the new RCA cable. Ive tried moving it around to no effect.
 
sound hound said:
Is there a way to do a search for the RCA cable in question to see if this is a common occurrence with the cable? Does it have RCA's at both ends or did you solder in the new cable? It doesn't seem to be an issue with length of cable, because you used the original cable before with extensions. I guess you could try adding the extensions to the new cable to see if it has any effects.
Click to expand...
https://www.amazon.com/dp/B00OYH6DCO?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1 It was just an average cable advertised as OFC (Which, looking at it, I doubt), and shielded....also doubtful...

I soldered it directly to the blades that insert into the corresponding part...call it a sheath.... tested all. good conductivity.

Good pickup with the extension: Correct, I had connected it with a good 4 feet of extension connects with no issues whatsoever. Seems the difference is the new RCA cable. Ive tried moving it around to no effect.

pic is the connections. Its a stock image, but identical to what I did: soldered to the spade thingees which connect to the other thingees.
 

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I wound up converting my 1019 to a power harness with a separate ground wire. I didn't have the AM tuner effect on mine, but there was too much hum with the ground through the right channel's RCA cable. It looks like the terminal is preinstalled in the power harness plug, so you should be able to add the wire, if you'd like, without replacing everything.
 
It certainly would be frustrating for you. I haven't bought new already constructed RCA cables. The old ones I have are pretty standard. There is a central wire that has its own insulation and a wire braid that surrounds it, which serves as the ground side of the connection, as well as offering shielding for the central conductor. It is simple and works pretty well. If the cable you bought doesn't have this structure, I would doubt that is a standard coax cable. Do you have another supplier that you can use other than Amazon?
 
Usually AM reception is because of a bad connection. Something crusty forms a point contact diode, essentially an un-tuned crystal radio, and whatever is fairly strong comes in. Might want to revisit the solder joints and the connections to the cartridge up at the headshell end.

Making sure the chassis ground wire is clean and tight would be a good idea too.
 
Thanks everyone. I ended up desoldering the new RCA's and since the extension RCA's didnt seem to draw AM when connected to the origional leads, I ended up snipping one end off each and soldering it into the turntable. Perfect now. The "OFC/Shielded"RCA's I brought off Amazon, after cutting them open, looked pretty cheap. And no shielding whatso ever.
 
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