questions about replacing the power cord

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mikezing

Active Member
Ill be replacing the power cord on my marantz 6300 soon and need some help figuring out what type of cord to get.

When i bought the tt, the voltage selector was set to 230. The power cord is attached to a ground inside the turntable, but the ground isnt used at the plug end. The current plug is a non-polarized 2 prong and the cable is 16awg. Im not sure if the cable is original, but I know that the plug isnt.

Should I get a three prong and use the ground or get a 2 prong to avoid having issues with grounding? If 2 prong, should I get a non-polarized or polarized? If polarized, where should I attach the hot end?
thanks guys!

UPDATE: I replaced the power cord with a polarized 2 prong 16awg cable. I replaced brown with black, blue with white, and removed the ground (thanks for the help with euro wiring guide). I still have the ground from the rca side attached to the amp. Everything is working great!!!
 
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You don't specify your location, so it is a bit hard to be totally prcesise. Local voltage? USA is 110v approx; Europe 230v.

You can just use 2 core cable and a 2 prong plug. If the TT uses a mains powered motor such as a shaded pole type, polarity is not an issue anyway; if a DC low voltage type then the mains is fed thru a transformer then a DC rectifier, so, again, no problem.

Leave the earth disconnected. Just connect the TT metalwork/ chassis to your amp chassis if there is hum or RF interference.
 
Sorry, thought I included that. Its currently set at 110v (USA). The ground is currently attached to my amp and Ive been plugging the tt into a surge protector (not the amp).

Can I use any 2 prong plug or do I have to use a non-polarized plug? If I use a polarized plug, does it matter which way I attach the wires?
 
Generally, the hot side will go to the power switch, neutral goes to the motor. Narrow blade would be the hot wire, assuming your outlet is wired correctly. If it originally used a 3 prong cord, I would probably re-fit a 3 prong plug on it. Honestly though, I've never seen a turntable that used one but I've also never owned one that was a multi-voltage rig either.
 
I am not quite sure what you are saying. "The power cord is attached to a ground inside the turntable, but the ground isnt used at the plug end. The current plug is a non-polarized 2 prong and the cable is 16awg."
Are you confusing ground with neutral?
 
The fat white shielded cable is the power cord. It has yellow/green, blue, and brown cables coming from it. It appears that the black cable (connected to the yellow/green) is grounded to a metal board elsewhere on the tt. Im pretty sure the sticker with the ground symbol is meant for the yellow/green cable. Currently, the yellow/green cable is cut at the plug end and not attached to anything. The blue and brown cables are attached to either prong of a 2prong non-polarized plug.

Was the yellow/green cable used for when is was setup for 220v or is it meant to be a ground for 110v? So, should I use 3prong, 2prong nonpolarized, or 2prong polarized? If polarized, where should I connect the hot wire?
 

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thats European coloring. The green/yellow is indeed an earth ground. The blue and brown are the power leads. Both are hot on a 220v circuit, and frankly I forget which is which in 110v service. The green/yellow is still a ground no matter what the voltage though, and it should most likely go to a third pin on the plug. If the plug isn't original, probably someone replaced a 3 prong with that 2 prong and simply didn't hook up the ground.

Trace the wires that are on the other side of where the power cord hooks up. If one goes to the switch, make that your hot wire. I'd probably use a 3 prong cord, but thats just me.
 
Brown is active, blue is neutral, and green/yellow is earth, for the power mains. The brown lead should be connected to the on/off switch for the turntable, which is often a micro-switch operated by the tonearm, and the blue lead should go to the motor, or the power supply for the motor. The blue neutral lead is connected to earth back at the building switchboard, so that the brown active lead is at AC 230V (no 220V or 240V any more!) or 110V with reference to it. That's so that the active won't be floating at higher voltages with respect to earth but will be within the nominal mains voltage.

It’s pretty rare (but not completely unknown) for turntables to earth the turntable via the power cord. So most have just 2 wire cords, and earth the turntable/tonearm to the amp via a dedicated earth lead, or via the signal earth on one channel. I’d just replace the cord with a 2 wire cord and plug to suit your local power sockets, and use a separate earth wire from the tonearm back to the amp phono earth connection. The other option is to replace the 2 pin plug with a 3 pin plug, and connect the green/yellow to the earth pin. You shouldn’t need a separate earth lead for the turntable then. I have seen Realistic turntables sold in Australia at Tandy that were earthed like that, via a three-pin plug to mains earth.
 
So, I can either use the ground on the power cord or the ground out of the tonearm. Is there a benefit to using one over the other?
Its currently setup with the ground out of the tonearm and I don't think there are any issues.

Thanks for the detailed info on power supply guys!
 
One thing that might hold me back from replacing the power cord on a turntable is the fact that the power jacks on the back of most vintage receivers is only 2 prong and not compatible with the modern cables that usually have the polarized design with a wider blade on one side, or are 3 prong.

Of course this is not an issue if you don't plug the turntable AC cord into the receiver but it reduces your choices. You can also use a non polarized cable.
 
mikezing said:
So, I can either use the ground on the power cord or the ground out of the tonearm. Is there a benefit to using one over the other?
Its currently setup with the ground out of the tonearm and I don't think there are any issues.

Thanks for the detailed info on power supply guys!
Click to expand...

If you use the ground out the tonearm (connect to the amp's metalwork or ground point), in theory you should get less noise, as the power cord ground is only linked to the chassis. As I mentioned before, I'd leave it out. If you connect both you run the risk of introducing hum loops.
 
I looked into getting a non-polarized replacement cable. The only non-polarized cables I can find are 18awg charging cables. Ill probably end up getting on of those and trying it, just to keep it similar to the original.
As far as I've read, replacing the power cord with an 18awg vs a 16awg with extra shielding shouldn't make any difference.
Can someone confirm this?
 
Probably won't make any difference. Some of my tables have 18ga cords, some have 16ga and I can't say I've ever noticed a change by replacing a cord, unless it was a case of replacing a totally shot cord with a new one. In that case, the change was usually that the thing worked again, where before it did not.
 
Back of my Kenwood TT says it draws 9w. 18 guage no problem. You could run a dozen+ turntables on an 18 guage cord.
 
I replaced the power cord with a polarized 2 prong 16awg cable. I replaced brown with black, blue with white, and removed the ground (thanks for the help with euro wiring guide). I still have the ground from the rca side attached to the amp. Everything is working great!!! :music:
 
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