How to stop feedback from my Linn LP12

Posted by: Mike Gundry on 02 November 2017

Hi
I need some advice, can you tell me how to stop feedback from my Linn LP12 whilst trying to play with Naim 202/200 and Naim stageline MC? Do I need to unplug everything just leave LP12 and stageline and connect each component to find the offending device?
Enclosed my system to date =
Linn Sondek LP 12 Ekos 11Ortofon Kontrapunktb UE Moving Coil Cartridge Universal Exchange
Linn Cirkus main bearing upgrade Linn LP12
Naim Stageline MC
Naim Allae speakers
Yamaha RX-A840
B & W 2000 IFS Centre Speaker
Densen Beat 400 upgraded to +
Naim NAC202
Naim NAP200
Chord Chrysalis 3 cables
JPL rear speakers
Antipodes Audio Gen1 DV2 4TB Music Server
NAD D 1050 USB DAC

Posted on: 03 November 2017 by james n

Do you mean you are getting a hum rather than feedback  ?

If so then i suspect disconnecting the Yamaha RX-A840 from the 202 will stop the hum. 

If it does then you need one of these

to break the ground path from the AV side of the system. Connect it between the Yamaha and the 202. 

James

 

Posted on: 03 November 2017 by Innocent Bystander

Feedback vs hum: simple test: if present when the pickup is raised with the stylus off the record it is not feedback (or at least, not acoustic feedback via the LP12, though an electrical fault or mis-connection somehow connecting the output of an amplifier stage to its input, which is rather unlikely). If it only happens with the stylus in contact with a record it could be feedback, in which event it would likely happen even without the turntable spinning, and usually is absent at lower volume control settings, suddenly kicking in at some point as the volume control setting is raised, and repeatable.

Posted on: 05 November 2017 by Mike Gundry

I think I've found the problem disconnected items and it was the Densen CDP turned it off stiil a bit there but I can live with that, Thanks all!  James curious to find out that connector is called might try and get one here in NZ?

Posted on: 05 November 2017 by james n

Mike - the device is just a ground loop isolator. You should be able to find one easily. It does sound like you have an earth loop somewhere (i take it you have a hum). If you have the LP!2 and the Densen CDP connected to the 202 (and the Yamaha disconnected) do you still get the hum. Also is the Densen close to the LP12 ?

James