Turntable Hum discussion

[Bloom@83]

AC motors in turntables are very susceptible to frequency and voltage variations and this is one area where a convertor can be useful. direct drives need not have that problem.

I do get a hum (not a hiss ) on my speakers (not audible at listening position) when my turntable plays (belt drive ).

Surprisingly, that hum appears when the AC is ON in the same room and not when it’s off.

To add to the confusion- the hum was there when I took the turntable to a technician. He suggested a cartridge change initially (which I did ) but the issue remained.

So he says it’s probably something to do with the power supply or the TT motor.
Interestingly , the hum increases when I move the tonearm to the centre , and is the lowest at the outer edge.

TT is plugged to my Belkin surge protector strip where CD players are also connected.

Was wondering if there was any inexpensive solution - if at all - to the problem. Else in the long run I would get a new TT.

 

[arj]

I do get a hum (not a hiss ) on my speakers (not audible at listening position) when my turntable plays (belt drive ).

Surprisingly, that hum appears when the AC is ON in the same room and not when it’s off.

To add to the confusion- the hum was there when I took the turntable to a technician. He suggested a cartridge change initially (which I did ) but the issue remained.

So he says it’s probably something to do with the power supply or the TT motor.
Interestingly , the hum increases when I move the tonearm to the centre , and is the lowest at the outer edge.

TT is plugged to my Belkin surge protector strip where CD players are also connected.

Was wondering if there was any inexpensive solution - if at all - to the problem. Else in the long run I would get a new TT.

the hum is most probably due to EMI/RFI or grounding . the EMI can be due to any device with a large enough motor eg AC/refrigerators and even computer SMPS power supplies can do that etc all .
Since it changes are you move it it is being caught by the cartridge not sure if a TT change will solve it. a simple isolation transformer (1:1) usually cleans all that out and you can test it out with a voltage stabiliser.

 

[Bloom@83]

the hum is most probably due to EMI/RFI or grounding . the EMI can be due to any device with a large enough motor eg AC/refrigerators and even computer SMPS power supplies can do that etc all .
Since it changes are you move it it is being caught by the cartridge not sure if a TT change will solve it. a simple isolation transformer (1:1) usually cleans all that out and you can test it out with a voltage stabiliser.

That’s helpful.
Apologies to the OP if it’s going OT. Post can be moved elsewhere.
@arj: I do have a refrigerator within 5 ft distance from the TT , but even when it’s turned off the hum’s there. No PC / laptop or any other electronics near it apart from my amps, DACs , CDPs which are on different wooden rack.

Where can I get a 1:1 isolation Transformer and how much would it cost ?
Will a LPS for the TT help ?

 

[jls001]

That’s helpful.
Apologies to the OP if it’s going OT. Post can be moved elsewhere.
@arj: I do have a refrigerator within 5 ft distance from the TT , but even when it’s turned off the hum’s there. No PC / laptop or any other electronics near it apart from my amps, DACs , CDPs which are on different wooden rack.

Where can I get a 1:1 isolation Transformer and how much would it cost ?
Will a LPS for the TT help ?

Before going the isolation transformer way, please check the grounding wire from your TT to phono preamp. There should be five wires coming out from the base of the tonearm. The colours should be red and green (right channel), white and blue (left channel) and one more wire which should be the ground wire from the inside of the tonearm. This is the wire that is extended as ground wire to the phono preamp. Check continuity of this wire. Ideally a continuity tester between the end of this wire to an exposed part of the tonearm tube or base should have continuity.

There are exceptions like Rega tonearms which simply uses the left channel's negative wire (blue) as ground wire. So you can also use a short wire to short left channel ground (barrel of the RCA) to phono preamp ground post.

<end of OT>

 

[arj]

That’s helpful.
Apologies to the OP if it’s going OT. Post can be moved elsewhere.
@arj: I do have a refrigerator within 5 ft distance from the TT , but even when it’s turned off the hum’s there. No PC / laptop or any other electronics near it apart from my amps, DACs , CDPs which are on different wooden rack.

Where can I get a 1:1 isolation Transformer and how much would it cost ?
Will a LPS for the TT help ?

You could try it out with a stabilizer first since that also has a transformer inside. see if makes a difference before buying anything.

Hums in TTs are frustrating to get right. I had a problem which drove me mad and then realised it was because the ground from TT to Phono was not a good connection. a tube lights choke can also cause a electromagnetic field and induce hum.
It could also be an improper ground at your place place an easy way to check that is to disconnect the ground cable in the TTs powerchord.

 

[mbhangui]

I do get a hum (not a hiss ) on my speakers (not audible at listening position) when my turntable plays (belt drive ).

Surprisingly, that hum appears when the AC is ON in the same room and not when it’s off.

To add to the confusion- the hum was there when I took the turntable to a technician. He suggested a cartridge change initially (which I did ) but the issue remained.

So he says it’s probably something to do with the power supply or the TT motor.
Interestingly , the hum increases when I move the tonearm to the centre , and is the lowest at the outer edge.

TT is plugged to my Belkin surge protector strip where CD players are also connected.

Was wondering if there was any inexpensive solution - if at all - to the problem. Else in the long run I would get a new TT.

When you move the tonearm towards the center and hum increases. That's a clue. What moves are the 4 tiny wires connecting the cartridge to the phono cables that connect to the phono preamp. Open your bottom and see if the delicate wires are firmly fastened?

Also check if your tonearm metal shows continuity with the TT ground. Also check if you touch the tonearm with your finger, does the hum level change?

 

[Bloom@83]

Got a couple of useful suggestions.Will try. Don’t want to divert main thread.

 

[Sean de Silva]

TT hum is a HUGE pita that I'm facing as well. Requesting mods to please hive off last few posts into a separate thread which can be continued

 

[sunder]

The colours should be red and green (right channel), white and blue (left channel) and one more wire which should be the ground wire from the inside of the tonearm.

Sir, are these color codes of the tonearm wiring in all branded TTs? or different brand TTs come with different color codes? Which color comes for the Earth? Thank you.

 

[jls001]

Sir, are these color codes of the tonearm wiring in all branded TTs? or different brand TTs come with different color codes? Which color comes for the Earth? Thank you.

Yes, these colours are common in all brands. Ground I've seen usually black.

 

[Bloom@83]

I do get a hum (not a hiss ) on my speakers (not audible at listening position) when my turntable plays (belt drive ).

Surprisingly, that hum appears when the AC is ON in the same room and not when it’s off.

To add to the confusion- the hum was there when I took the turntable to a technician. He suggested a cartridge change initially (which I did ) but the issue remained.

So he says it’s probably something to do with the power supply or the TT motor.
Interestingly , the hum increases when I move the tonearm to the centre , and is the lowest at the outer edge.

TT is plugged to my Belkin surge protector strip where CD players are also connected.

Was wondering if there was any inexpensive solution - if at all - to the problem. Else in the long run I would get a new TT.

The main puzzling thing is that the hum goes off when room AC is off , and comes back on switched on.

 

[aeroash]

The main puzzling thing is that the hum goes off when room AC is off , and comes back on switched on.

Since you've mentioned that the AC and the TT are in the same room, I'm assuming it's connected to the same electrical line. I suspect your AC Compressor is inducing Line Noise (Conductive Noise).

As an experiment, try pulling an extension chord from another outlet in the house (not the same room) to power your TT. Try from all outlets if you must. You can at-least rule out the AC motor if the test fails.

 

[General_sound]

Hum is a phenomenon which almost all tt owners face. However I don't feel it is an insoluble issue. Pease tell us the make of your tt, the cartridge in use and whether connected directly to an amp or through a phono stage. The reason I am asking is because some tt's are more prone to hum because of motor type, and equally some cartridges i.e. Grado pick up hum more easily. In addition earthing, ground loops, proximity to other equipment/ led lighting/ wall warts all contribute their share. We have to look at each issue.

 

[Bloom@83]

Hum is a phenomenon which almost all tt owners face. However I don't feel it is an insoluble issue. Pease tell us the make of your tt, the cartridge in use and whether connected directly to an amp or through a phono stage. The reason I am asking is because some tt's are more prone to hum because of motor type, and equally some cartridges i.e. Grado pick up hum more easily. In addition earthing, ground loops, proximity to other equipment/ led lighting/ wall warts all contribute their share. We have to look at each issue.

Ortofon 2M Blue cart connected to ifi iPhono pre.
Project debut carbon belt drive TT.
It’s not a problem of either cart or phono or grounding because I have changed(upgraded ) cart , phono pre , even preamplifier.

As I mentioned the hum appears and goes with the AC being turned on and off in the same room.

Also , with the AC on , the hum intensity increases when I move the tonearm manually towards the centre, and is lowest at the outer edge.

At very high volume, during quiet passages of music , the hum is audible from listening position , otherwise not. So not a dealbreaker for me.

 

[Mayasandra_l]

I have a Sony automatic Player LX300 which also produces hum not from the speakers but from the player itself. I would be keenly following this thread for a solution. Thanks.

 

[sunder]

Yes, these colours are common in all brands. Ground I've seen usually black.

Thank you. Regards.

 

[General_sound]

Thanks. That's good equipment. I had a similar problem of hum from my Dual 1019, which was detracting from the listening experience. After going thru various other tt fora, the following emerged. 1. Some tt motors are poorly shielded and may contribute to hum or noise. In this case MU shielding was recommended. Now I have no idea what this is. So stayed away. 2. Experiment with different carts. Discovered that Shure M 75 picked up least hum. 3. Also experiment with keeping power and audio cables apart and fitting ferrite rings. Put two on the phono cable. Surprisingly there was a difference.
All above is proviso other aspects like proper earthing, clean connections, good interconnects etc are adhered to.
In a Project tt changing a cart requires some skill as the connectors
are very delicate so this may not be an option. Also there are many discussions on the net about Project motor noise and hum and solutions thereon.
I cannot comment on the AC, however do consult a good electrician . Also, measures suggested by Aeroash can be tried.

 

[arj]

Ortofon 2M Blue cart connected to ifi iPhono pre.
Project debut carbon belt drive TT.
It’s not a problem of either cart or phono or grounding because I have changed(upgraded ) cart , phono pre , even preamplifier.

As I mentioned the hum appears and goes with the AC being turned on and off in the same room.

Also , with the AC on , the hum intensity increases when I move the tonearm manually towards the centre, and is lowest at the outer edge.

At very high volume, during quiet passages of music , the hum is audible from listening position , otherwise not. So not a dealbreaker for me.

Have you tried moving the TT to a different point ? Some years back I used to get a hum due to the Choke from a Tubelight ..changing the angle of the phonostage helped there...finally got rid of the tubelight.

Not sure of its the angle of tonearm which is causing interference with something ? Since when you move it to the center the angle the tonearm causes also changes.

 

[Bloom@83]

Have you tried moving the TT to a different point ? Some years back I used to get a hum due to the Choke from a Tubelight ..changing the angle of the phonostage helped there...finally got rid of the tubelight.

Not sure of its the angle of tonearm which is causing interference with something ? Since when you move it to the center the angle the tonearm causes also changes.

I can’t move the TT to a different point unfortunately. Not practically feasible. I’ll try to power it from a different room as suggested earlier. Also checked that the AC and TT power lines are going to different MCBs.

 

[arj]

try twisting it at th same spot to maybe 45 degrees and see if it is the same amount of hum at all points ?