Hum gone.

[Audiotfoot]

I've been fighting an intermittent hum in my Dual 704 for some time and had decided it had to be in the tonearm wiring somewhere. Searching through here for solutions to hum a couple threads about Duals were found. In one (or maybe both) hints about cleaning and adjusting the contact board behind the cartridge sled were given.

A thorough cleaning with DeOxit. necessitated the adjustment as the contact board fell out during the process. No idea which process did the job, but there is no more hum.

Thanks everyone.

 

[Hajidub]

Good job Audiotfoot? Have a Dual 1015 with a hum. Not sure if it's the cart (too lazy to swap and I don't use it anyways...now). The sled contacts have been cleaned, but the hum was there even with the sled removed (probably rules out the cart, I just realized). Mine has that jenky DIN to RCA factory adaptor which might be bad. Either way the hum comes and goes if I touch the tonearm or platter.

 

[Patrice B]

I had hum with a Dual 1019: bad contact in the headshell sled and amazingly, the ground wire shouldn't be connected as it causes...hum!

 

[Audiotfoot]

Good job Audiotfoot? Have a Dual 1015 with a hum. Not sure if it's the cart (too lazy to swap and I don't use it anyways...now). The sled contacts have been cleaned, but the hum was there even with the sled removed (probably rules out the cart, I just realized). Mine has that jenky DIN to RCA factory adaptor which might be bad. Either way the hum comes and goes if I touch the tonearm or platter.

There was no hum with the sled removed, but touching the head shell caused one so it was pretty obvious mine was cart related. I wish you good luck solving our problem.

 

[Audiotfoot]

I had hum with a Dual 1019: bad contact in the headshell sled and amazingly, the ground wire shouldn't be connected as it causes...hum!

That's strange. But if disconnecting the ground eliminated the hum, well, hmmm. Oops, no pun intended, just puzzlement.

 

[Patrice B]

That's strange. But if disconnecting the ground eliminated the hum, well, hmmm. Oops, no pun intended, just puzzlement.

Yes, I know, weird! But it's hum free with the ground disconnected, go figure!