Home » Audio » Source » Grados,ortophons,shures and AR turntable hum
Grados,ortophons,shures and AR turntable hum [message #12461] Tue, 16 August 2005 12:01 Go to next message
Russellc is currently offline  Russellc
Messages: 397
Registered: May 2009
Illuminati (1st Degree)
Hello.
As many of you know, I use a modified AR "the turntable". Previous to modification, I used the ortophon super OM 20. I upgraded to the OM 30. with both of these cartridges, there was some hum that I could usually get down to an acceptable level. After changing to a Shure V15Vxmr, I was able to almost completely eliminate hum on the phono, even with Altec A7 speakers. Having used the shure for a while, I decided to re-mount the OM 30 for a comparison. Long story short, it hums badly. I have long heard the AR wisdom to avoid grados because of hum, but have never had this problem leveled at ortophon. Anyone else have hum with ortophon? The only change I have made with the
shure that was not in place with the ortophon would be changing the original inner platter and original outer platters (both aluminum) for an inner platter of delrin, and an acrylic outer platter. Perhaps these lent some modicom of shielding that was sufficient
to prevent the Ortophon from humming. I certainly dont remember this level of hum before. This is with the normal ground wire connected with the shure, also connected with the Ortophon, as well as another ground wire that is on the table, that reduces the level somewhat.
Any thoughts on humming AR/ortophon stories out there?

Thanks,
Russellc

Re: Grados,ortophons,shures and AR turntable hum [message #12462 is a reply to message #12461] Tue, 16 August 2005 13:45 Go to previous messageGo to next message
Dominic is currently offline  Dominic
Messages: 29
Registered: May 2009
Chancellor

Maybe the hum comes from your pre-amp?

Re: Grados,ortophons,shures and AR turntable hum [message #12463 is a reply to message #12461] Tue, 16 August 2005 17:15 Go to previous messageGo to next message
Manualblock is currently offline  Manualblock
Messages: 4973
Registered: May 2009
Illuminati (13th Degree)
Say Russell; do you have both ground wires connected? and if so how does it do if you remove one of them? Have you tried swapping the positive leads on the cartridge pins? And hum is usually simple in Turntables; so are all the wires tight and have continuity? I have had that happen before, loose wire.

Re: Grados,ortophons,shures and AR turntable hum [message #12464 is a reply to message #12462] Wed, 17 August 2005 06:01 Go to previous messageGo to next message
Chris Denyer is currently offline  Chris Denyer
Messages: 9
Registered: May 2009
Esquire
Thats what I think it may be. I had a similar problem once with hum, but I seperated the phono pre from the tube pre amp I use, and hey presto-no hum.

Re: Grados,ortophons,shures and AR turntable hum [message #12465 is a reply to message #12463] Wed, 17 August 2005 12:22 Go to previous messageGo to next message
Russellc is currently offline  Russellc
Messages: 397
Registered: May 2009
Illuminati (1st Degree)
Yes, with the ortophon it was quieter with both wires connected. The shure is just as quiet either way. Removing either wire increases the hum.

Russellc

Re: Grados,ortophons,shures and AR turntable hum [message #12466 is a reply to message #12464] Wed, 17 August 2005 12:28 Go to previous message
Russellc is currently offline  Russellc
Messages: 397
Registered: May 2009
Illuminati (1st Degree)
I use two tube preamps, either one the ortophon hums, the shure doesnt. My counterpoint is a little quieter than the Audio by Van Alstine super pas III, but just a litte. They are both amazingly quiet with the shure, even with Altec A7 (well over 100db efficient).
The only real change is the platters. The Ortophon hummed a little before, but was only noticeable with no music playing. Again, this is with very efficient speakers that are vewry revealling of hum.

Russellc

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