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garytpaul
Contributor I
Dec 7, 2024 12:24 PM UTC
Answered

Turntable Hum

Hi. My set up is a Rega Planar 1, Pro-Ject Phono Box MM pre-amp, and an Era 300.

The minute I turn the Rega on a massive hum is present. I have scoured the internet and tried everything I can find.

Tried grounding the amp and the left channel output on the Rega. Tried grounding to each other, and each one to a radiator. 

Have tried all combinations of plugs being in the same expansion lead or not.

I have laid it all out so no cables are crossing. 

But no improvement.

If I plug the Rega straight into the Era 300, there is no hum (thought the sound is nor great, but just about listenable).

I also get the buzz when I use a Bose speaker I had to hand to test.

Any ideas?

TIA.

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garytpaulAnswer
Contributor I
Dec 14, 2024 11:45 PM UTC

Okay, so problem solved. And you can all have a good chuckle at my expense. 
 

I was convinced I had bought a RP1. 
 

I in fact have a 1 Plus. Which has a built in Phono Stage. 

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12 replies

Stanley_4
Stanley_4
Grand Maestro
Dec 7, 2024 9:00 PM UTC

Failed preamp would be my first guess.

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    garytpaulAuthor
    Contributor I
    Dec 13, 2024 6:30 PM UTC

    Okay, so: I returned the pre-amp and got a replacement. 
     

    Still the same issue - very loud hum and the music buzzes when it comes through. 
     

    Thoroughly tested the cables and everything. 
     

    Any more ideas?

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    Stanley_4
    Stanley_4
    Grand Maestro
    Dec 13, 2024 6:45 PM UTC

    DON’T play anything, but try plugging something like a CD player into the phono preamp to see if it hums. If it doesn’t you have confirmed the preamp and 300 input are good.

    Take the turntable to somewhere you can plug it into a Phono input on a receiver and see if it hums there too. If it doesn’t it is good too.

    Re-reading your original post on power cords, when on the same power strip did you try reversing just one plug in the socket at a time to see if the hum reduces. You’d need to work through all the combinations of plug directions.

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      garytpaulAuthor
      Contributor I
      Dec 13, 2024 7:05 PM UTC

      Hi Stanley. Thanks for your help with this. 
       

      I e tested various combinations of devices and am pretty happy that the 300 input connection is good, as is the turntable output. 
       

      We are in the UK and have the three pin plug system so cannot reverse them - unless I am misunderstanding what this means. 
       

      I wonder though - the amp has an earthbound in the plug but it’s a dummy and just plastic. As the Rega is grounded internally through the left put channel, could this be an issue?

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      buzz
      buzz
      Grand Maestro
      Dec 13, 2024 8:50 PM UTC

      “Grounds” are usually connected from a dedicated “Ground” terminal on the turntable to a dedicated “Ground” terminal on the preamp. Additional Ground connections from chassis to chassis can cause trouble.

      Do you have hum if you disconnect the turntable while connecting the preamp output to Line-In? Likewise, if you skip the preamp and directly connect the turntable to Line-In, is there any hum (likely at a lower level)? Obviously you cannot listen to music with either of these connections. This is just an attempt to identify the hum source.

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      garytpaulAuthor
      Contributor I
      Dec 13, 2024 8:56 PM UTC

      There is no hum when I connect the Rega straight into the line in on the 300. The sound isn’t great, but it is listenable.
       

      no hum when just the amp plugged into the line in. The hum starts the second I power in the turntable.    
       

       

       

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      MoPac
      MoPac
      Headliner III
      Dec 13, 2024 8:57 PM UTC

       Is the preamp power cable a three prong?  If so lift the ground with a cheater adapter if they have those in the UK.

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      buzz
      buzz
      Grand Maestro
      Dec 14, 2024 1:33 AM UTC

      As you perform my tests above, power the turntable. When you have the turntable connected normally, is there any change in the hum as you move the tonearm closer to the center of the record?

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      garytpaulAuthor
      Contributor I
      Dec 14, 2024 9:33 AM UTC

      No, there is no discernible change in the hum as I live the tonearm. 

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      garytpaulAuthorAnswer
      Contributor I
      Dec 14, 2024 11:45 PM UTC

      Okay, so problem solved. And you can all have a good chuckle at my expense. 
       

      I was convinced I had bought a RP1. 
       

      I in fact have a 1 Plus. Which has a built in Phono Stage. 

      Translate
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