Turntable Hum

[SimpleTheater]

I’m quite aware how difficult it can be to figure out the cause of turntable hum, but I’ve narrowed it down and hoping someone can help.

1. Integrated amp is silent on phono stage when no cables are connected
2. Hum exists regardless if TT is turned on or even plugged in to an outlet
3. Hum is reduced significantly, but not eliminated when I disconnect the ground (doesn’t matter if which end, amp or TT)

I’ve used different interconnects, but no difference. I’ve moved the TT 3ft from the amp and no difference.

Any ideas?

 

[Angsty]

Poor TT cable shielding?

 

[SimpleTheater]

Poor TT cable shielding?

If you’re correct, are you saying only a new TT will fix the issue?

 

[dougi]

perhaps try a cable with the shield only connected at one end. The Project phono cable has that but it's capacitance is a bit high for most mm carts.

 

[sq225917]

If it hums with the tt unplugged from mains then its either bad tonearm cable, lack of proper shielding or more likely you have a tiny voltage running across the case of the integrated. You dont have to earth the arm to the integrated, any gnd will do.

A few wires with crocodile clips are your friend here.

Which integrated is it? Does it have xlr sockets on it?

 

[JeffS7444]

Ground loop maybe?

 

[SimpleTheater]

If it hums with the tt unplugged from mains then its either bad tonearm cable, lack of proper shielding or more likely you have a tiny voltage running across the case of the integrated. You dont have to earth the arm to the integrated, any gnd will do.

No hum when TT is unplugged.

Which integrated is it? Does it have xlr sockets on it?

Yamaha A-S2100. No TT xlrs.

Also, problem recently started.

 

[sergeauckland]

If you’re correct, are you saying only a new TT will fix the issue?

Not necessarily, just replace the cable to the amp.
Turntable hum can also be caused by incorrect earthing. The turntable metalwork should be connected to mains earth. The arm should he insulated from the turntable's metalwork and should be earthed only to the amplifier. If it's not possible to insulate the arm from the turntable, then the turntable has to be double-insulated such that it doesn't have a mains earth.
Finally, the cartridge body should be earthed to the headshell, not to one of the audio pins. Shure cartridges had a removable linking strap for this. If the cartridge body is permanently earthed through one audio pin, then it should be insulated from the headshell.

S

 

[SimpleTheater]

Not necessarily, just replace the cable to the amp.
S

The ground cable? I did change rca cables and kept the ground connected, but that didn’t do anything.

 

[Bob from Florida]

Disconnecting the ground implies a ground loop. Can you provide more details? What type of turn table? Can the tonearm cable be unplugged from the arm base? What cartridge are you using?
One thing you can do to eliminate the cartridge is short the plus and minus for each channel together - best done very carefully. Whatever you use make sure it is non magnetic - you don't want anything attracted to the cartridges mechanism.

 

[SimpleTheater]

Disconnecting the ground implies a ground loop. Can you provide more details? What type of turn table? Can the tonearm cable be unplugged from the arm base? What cartridge are you using?
One thing you can do to eliminate the cartridge is short the plus and minus for each channel together - best done very carefully. Whatever you use make sure it is non magnetic - you don't want anything attracted to the cartridges mechanism.

Teac TN-550
The tone arm cable cannot be disconnected from the base.
Denon DL-103R MC

 

[DimitryZ]

I recently had a vexing tt hum problem that was finally traced not to the tt, not to the phono preamp, but to the bad IEC socket on the line preamp, which was loosing the ground connection.

 

[Bob from Florida]

Teac TN-550
The tone arm cable cannot be disconnected from the base.
Denon DL-103R MC

Nice table!
Does your integrated support moving coil cartridges!

 

[SimpleTheater]

Nice table!
Does your integrated support moving coil cartridges!

Yes, and it’s set to MC.

This is a new problem, had the setup a couple of years, without issue.

 

[Bob from Florida]

Yes, and it’s set to MC.

This is a new problem, had the setup a couple of years, without issue.

New problem with previous history of working correctly - got it.
If I understand correctly the hum occurs with the table connected even with the DC power supply disconnected. Try disconnecting the cartridge and evaluate the hum with wires un-shorted and shorted. If it still hums shorted then possibly an internal turntable wiring issue - depends on how it is wired. If no hum shorted then try another cartridge.

 

[SimpleTheater]

New problem with previous history of working correctly - got it.
If I understand correctly the hum occurs with the table connected even with the DC power supply disconnected. Try disconnecting the cartridge and evaluate the hum with wires un-shorted and shorted. If it still hums shorted then possibly an internal turntable wiring issue - depends on how it is wired. If no hum shorted then try another cartridge.

The Teac has a simple cartridge head removal, by just loosening and removing. With no cartridge connected almost no hum. How should I short the tonearm? Paper clip across the terminals?

 

[Bob from Florida]

The Teac has a simple cartridge head removal, by just loosening and removing. With no cartridge connected almost no hum. How should I short the tonearm? Paper clip across the terminals?

This is with the ground wire connected between TT and Integrated? If so and the hum became less with the cartridge removed you may have found your problem. Do you have another cartridge to try?

 

[SimpleTheater]

I put in the original cart and no hum. I put the Denon cart back on and the hum returned. Bummer, I really liked that Denon cart.

 

[SimpleTheater]

Anyone have cart recommendations? Like to keep it under $400. MM / MC, doesn’t matter to me.

 

[Bob from Florida]

I put in the original cart and no hum. I put the Denon cart back on and the hum returned. Bummer, I really liked that Denon cart.

Denon's are not that pricey.... Just get another one or try a Hana EH from Music Direct - 60 day return - and use the MM input. If your MC input has loading of around 470 ohms the EL version will work. The Hana is quite a bargain.