Music Hall Classic humming issue


Just purchased a Music Hall Classic off this site. Hooked it up to Kanto YU6 speakers using the built in pre-amp and I’m getting a 60 cycle hum that, through process of elimination, I’ve determined is coming from the turntable. Checked/swapped out wires, checked outlets, ground wires are set…hum is still there as soon as I turn on the turntable. Any ideas? Would going through an external pre-amp eliminate that? Thanks!
fredb72

I don’t think, see how, it could be 60Hz ground loop hum. The TT motor is powered by a plug in 120Vac two blade step down DC power supply. No equipment ground there.

The power supply’s 120V plug in 2 blades does not appear to be polarized, meaning the unit can be plugged in 180 degrees either way. You might try reversing it both directions.

Note the TT has a ground post lug on the back side of it. Did you run a ground wire from the ground post lug to the ground post lug on the Kanto YU6 speaker?

Are you using a pair of good shielded phono interconnect cables?

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Thanks - yeah, ground wire on both turntable and speakers and I’m using the cables that came with the turntable. I’ll try flipping the power supply plug and see if that helps. 

@fredb72

How close is the TT to the Kanto YU6 speaker with the amplifier?

Your problem could be the TT cartridge and or RCA interconnects is picking up EMI from the 120Vac power cord. Try to increase the distance between the TT and the speaker with the amp. Make sure the RCA interconnects are not close to the AC power cord.

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You should have the Phono/Line switch set to Line.

https://cdn.shopify.com/s/files/1/0710/4649/6578/files/music-hall-classic-turntable-manual.pdf?v=1677776693

7. PHONO/LINE switch
Use this switch to select the audio output type appropriate to your connected audio device, such as a stereo system or
an amplifier. If plugging into a phono input make sure the switch is set to PHONO.

If plugging into a line input make sure the switch is set to LINE.

 

NOTE:
Be sure to connect the ground terminal firmly to the amplifier or receiver to avoid pops.
If this connection is not made or is loose, a power source "HUM" will result.
You can also use a line input by setting the PHONO/LINE switch at the rear of the turntable to LINE.
*When using the LINE input the ground connection is not required*

Try it without the ground wire connected to the Kanto YU6 speaker amplifier ground post lug.

@fredb72 - what's youe setup - e.g.

  • Cartridge
  • phono amp or pre-amp/amp with phono
  • cable from turntable into phono input

Hum can be very difficult to get rid of and can be due to

  • the cables from the turntable
  • the grounding on the arm
  • the phono stage (when it has a 2 prong plug or wal-wart supply)

Regards - Steve

@jea48 Thanks! I think you nailed it with the EMI from the power cord. Even moving the power cord to the lower outlet on the wall made a difference and then as I experimented moving the TT farther away from the speakers, the hum lowered. So I think I’ll need to run an extension cord to an outlet further away from the TT and hopefully that should do the trick!

@fredb72

It sounds like the EMI (Electric/Magnetic fields from the 120V unshielded power cord that feeds the amplifier of the Kanto YU6 is inducing 60Hz EMI noise on the DC power cable that feeds the phono preamp in the TT. There could also be AC noise going back out on the 120Vac power cord caused from the power supply in the Kanto YU6 amp.

I would try to keep the TT as far as possible from the Kanto YU6 amp. I would also suggest you try, buy, a shielded power cord for the Kanto YU6 amp.

Example:

I found this cheap one doing a search on Google. How well is it shielded??? Don’t know...

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NEMA 5-15P to IEC C13 Shielded Power Cable - 14AWG STJ

https://cablechum.com/products/nema-5-15p-to-iec-c13-shielded-power-cable-14awg-sjt?variant=39782258381

$11.35 CAD + shipping.

You may find something cheaper. Note, lots of cheap 18AWG shielded power cords but hard to find any wire size bigger than shielded 18AWG.

Step up to aftermarket audio grade shielded power cords and the price jumps up sharply.

 

FWIW, an outboard phono preamp might make a difference. Not sure it would be worth spending money to find out though.

 

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