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"New" turntable setup is creating a hum only on the phono stage

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Help.

 

I have just got my Denon DP 60L from Japan yesterday. Opened the box (very well packed) and having setup the table (which appears to be in excellent condition - speed is spot on) I have a hum.

 

I have a naim nac 82 pre which has a MM phono stage to match the AT 100E brand new cart and a Nap 250.2 power amp. I will change the board to MC and get a better cart only if I can isolate and get rid of the hum.

 

There is no hum on the CD or Dac even when the phono is connected so I know it is isolated. As this is my first turntable I have very few ideas.

 

The step down transformer is new and when I disconnect the power from the Dectet board and turn the volume up there is a crackle of sorts on the phono stage so I am not sure what is happening with the earth connection?

 

Any ideas would be greatly appreciated. I don't think it is the turntable as it was sold by a reputable dealer in Japan.

 

Thanks in advance.

 

Peter

 

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Help.

 

I have just got my Denon DP 60L from Japan yesterday. Opened the box (very well packed) and having setup the table (which appears to be in excellent condition - speed is spot on) I have a hum.

 

I have a naim nac 82 pre which has a MM phono stage to match the AT 100E brand new cart and a Nap 250.2 power amp. I will change the board to MC and get a better cart only if I can isolate and get rid of the hum.

 

There is no hum on the CD or Dac even when the phono is connected so I know it is isolated. As this is my first turntable I have very few ideas.

 

The step down transformer is new and when I disconnect the power from the Dectet board and turn the volume up there is a crackle of sorts on the phono stage so I am not sure what is happening with the earth connection?

 

Any ideas would be greatly appreciated. I don't think it is the turntable as it was sold by a reputable dealer in Japan.

 

Thanks in advance.

 

Peter

 

Hi Peter.

did you earth the phono cable to your preamp and earth the table as well if there is an earth tag on the back of the turntable ?

regards

Duc

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Hi Peter.

did you earth the phono cable to your preamp and earth the table as well if there is an earth tag on the back of the turntable ?

regards

Duc

Hi Duc,

 

Yes I have earthed the phono cable to the preamp. There is no earth tag on the back of the turntable.

 

When I turn the volume up on the phono setting on preamp even without power to the turntable there is a buzzing in the tweeter. Only on the phono stage.

 

Cheers,

Peter

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Maybe disconnect all other devices from your setup i.e. cd and network players etc. If the hum stops you can find the culprit by plugging them back in one by one. I recently had a similar problem which turned out to be an ethernet over power adapter making a buzz through my phono input.

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Hi Duc,

 

Yes I have earthed the phono cable to the preamp. There is no earth tag on the back of the turntable.

 

When I turn the volume up on the phono setting on preamp even without power to the turntable there is a buzzing in the tweeter. Only on the phono stage.

 

Cheers,

Peter

 

Hi Peter.

if that is the case I should check the earth wire and the tonearm metal parts to made sure it is still doing it job .

buzzing normally tell you that there is an earthing problem .

Duc

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Mine has a very slight hum i just gatherd my phono amp needs a service as it mas made in 1993

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You can also disconnect the earth cable to see if the hum disappears

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This is getting more puzzling. There is no buzz in the tweeter when I remove the RCA connection and I leave the earth connection from the turn table to pre-amp. As soon as I reconnect the RCA connections the hum re-appears.

 

Probably rules out the stepdown transformer as the issue. Not sure where to head now?

Edited by Nap250

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I wonder if it could be the phono card, it was installed this morning?

 

@@Hensa

@@ABG

Edited by Nap250

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This is getting more puzzling. There is no buzz in the tweeter when I remove the RCA connection and I leave the earth connection from the turn table to pre-amp. As soon as I reconnect the RCA connections the hum re-appears.

 

Probably rules out the stepdown transformer as the issue. Not sure where to head now?

 

that sound like earth loop . just disconnect the earth wire like FR said and see what happen

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Earth wire disconnected and I still have some hum (perhaps marginally less) and now there is also buzzing.

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This is getting more puzzling. There is no buzz in the tweeter when I remove the RCA connection and I leave the earth connection from the turn table to pre-amp. As soon as I reconnect the RCA connections the hum re-appears.

 

Probably rules out the stepdown transformer as the issue. Not sure where to head now?

 

In my experience, Naim phono earthing is problematical.

 

Did I understand you correctly?  When you remove the phono cable RCAs from the NAC82-with-phono-boards ... does the tweeter buzz disappear?

 

Can you try a different (non-Naim) phono stage and then plug the output from this (@ line level) into the NAC82?

 

 

Andy

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In my experience, Naim phono earthing is problematical.

 

Did I understand you correctly?  When you remove the phono cable RCAs from the NAC82-with-phono-boards ... does the tweeter buzz disappear?

 

Can you try a different (non-Naim) phono stage and then plug the output from this (@ line level) into the NAC82?

 

 

Andy

Hi Andy,

 

Yes when I removed the RCA connections the tweeter buzz and hum stopped.

 

I have no idea what just happened but I reconnected the earth connection to the pre-amp and No buzz or hum.

 

Time to enjoy the new turntable and fingers crossed that this continues.

 

Cheers,

Peter

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So a bad connection - metal to metal contact wise

I always clean or scour the wire or the connector

Sometimes with older gear the connection wires inside there sheath goes green and need replacing

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Hi Andy,

 

Yes when I removed the RCA connections the tweeter buzz and hum stopped.

 

I have no idea what just happened but I reconnected the earth connection to the pre-amp and No buzz or hum.

 

Time to enjoy the new turntable and fingers crossed that this continues.

 

Cheers,

Peter

 

Yes, enjoy the new TT, Peter!  And when you decide it's here to stay ... time to buy a new (non-Naim) phono stage and use the NAC82 as a preamp. ;)

 

 

Andy

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Thanks Andy,

 

@@andyr

 

I think the next step is a better cart. I was thinking the Dynavector DV20X2 as a good match for this table.

 

Phono stage is a bit more problematic due to no room left on the rack.

 

Cheers,

Peter

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Glad to hear you got your grounding issue sorted Peter.  Enjoy your new TT.

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As you said in your opening post - you were thinking of changing over to MC ... which will require MC boards instead of MM boards in the NAC82.

 

I don't know if you (having Naim equipment) inhabit Pink Fish Media but there's a UK company who makes upgrades for Naim amps - pre & power.  (Sorry, forget the name.)

 

His phono cards are supposed to sound better than Naim's.

 

 

Regards,

 

Andy

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Thanks Andy,

 

I already have the MC boards. Harry lent me the MM boards to see how I like the table before I decide whether I want to spend more money.

 

Switching the boards was relatively easy for him to do.

 

Regards,

Peter

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Hi Andy,

Yes when I removed the RCA connections the tweeter buzz and hum stopped.

I have no idea what just happened but I reconnected the earth connection to the pre-amp and No buzz or hum.

Time to enjoy the new turntable and fingers crossed that this continues.

Cheers,

Peter

Good to hear your problem is fixed. Enjoy music! Don't upgrade too fast, spend some time with your TT and music first. First upgrade would be a separate phono I reckon.

Sent from my iPad using Tapatalk

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Try bridging the earth (cold) side of the plugs on the RCA's

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Try bridging the earth (cold) side of the plugs on the RCA's

what does that mean? How do I do it?

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My rca's have a metal body and I just connected the two bodies with a wire. If the bodies are plastic then the metal outer cylinder of the rca's will have to be connected somehow, you could just try a temporary connection to see if it makes a difference.

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Thanks Waricle, at the moment it is fine. No further issues.

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