AudioAl
pfm Member
I don't understand electronics as I am not a engineer , Not sure the OP will also understand as he does not own a multi meter , Is that OK for a answer ?
Earthing issues with Technics 1210/OL arm
- Thread starter kimmiles
- Start date
I don't understand electronics as I am not a engineer , Not sure the OP will also understand as he does not own a multi meter , Is that OK for a answer ?
I have to say that it is not really electronics or even engineering. It is simple maths - A = B x C. If I give you any two of the three, you cannot help but be able to calculate the third.
There is lots that I would do before considering shipping anything anywhere, so it depends on what the OP wants to do.
The chances of an internal short must be very remote indeed.
I assume that you have had a cart' connected all the time so far? If so, do you still get hum if any or all of the cart' tags are disconnected?
From only exactly what you have said so far, things do not make sense. So either I have missed something, you have written something that means something different when read, or there is something totally missing.
It is difficult to imagine how connecting the arm earth makes an already bad problem worse, just for starters.
If you did borrow a meter, you just check continuity (resistance) between all of the arm wires, the wires and the arm itself and arm wires to the earth - dead simple, tedious, but takes just a very few minutes.
I do not know the deck at all. What is the power supply cable to the TT? Is it twin or twin and earth? If twin, how is it earthed? Seperate earth cable?
From only exactly what you have said so far, things do not make sense. So either I have missed something, you have written something that means something different when read, or there is something totally missing.
It is difficult to imagine how connecting the arm earth makes an already bad problem worse, just for starters.
If you did borrow a meter, you just check continuity (resistance) between all of the arm wires, the wires and the arm itself and arm wires to the earth - dead simple, tedious, but takes just a very few minutes.
I do not know the deck at all. What is the power supply cable to the TT? Is it twin or twin and earth? If twin, how is it earthed? Seperate earth cable?
So the suggestion was to earth the arm to the unearthed chassis. That way the body of the arm would float at the same voltage as the chassis. Surely the chassis cannot be earthed via the return of the phono leads??????? Are the phono leads attached to the tonearm or are there connectors in the casework of the deck?
This would be SO much easier with the deck in front of me, with a meter.
This would be SO much easier with the deck in front of me, with a meter.
Without it in front of me, it is difficult to suggest more than what @AudioAl has suggested - a very noisy motor/power supply, but if it was so common and so bad, the deck would never sell.
With no earth lead except the one from the tonearm, there can be no loop, except within the deck itself. If there is even worse hum with the arm earth disconnected, it must be the cart' leads themslves picking up the noise. so earthing the body of the arm would shield the arm leads, presumably.
With no earth lead except the one from the tonearm, there can be no loop, except within the deck itself. If there is even worse hum with the arm earth disconnected, it must be the cart' leads themslves picking up the noise. so earthing the body of the arm would shield the arm leads, presumably.
Is this a simple way of isolating where the problem is.
the turntable itself is completely powered down. The tonearm has cartridge installed and phono leads attached to his amplifier and sound available to the speakers.
He powers up the amplifier, If it is apparent that hum is present with no power to turntable what so ever then am I correct in saying it’s nothing to do with the turntable itself?.
If on the other hand the same procedure is carried through and there is complete absence of hum before the turntable is power up then it’s a problem or issue between tonearm and turntable combination somewhere ?.
Apologies if my wording as a little basic !.
the turntable itself is completely powered down. The tonearm has cartridge installed and phono leads attached to his amplifier and sound available to the speakers.
He powers up the amplifier, If it is apparent that hum is present with no power to turntable what so ever then am I correct in saying it’s nothing to do with the turntable itself?.
If on the other hand the same procedure is carried through and there is complete absence of hum before the turntable is power up then it’s a problem or issue between tonearm and turntable combination somewhere ?.
Apologies if my wording as a little basic !.
Well, very sadly, I have removed the OL arm from the SL1210 and put the tt in another room, reconnected the arm to my amp and the hum is still there!
I guess that that means the arm is at fault and will have to returned to OL.
Very disappointing.
Many thanks for everyone's help and advice
I guess that that means the arm is at fault and will have to returned to OL.
Very disappointing.
Many thanks for everyone's help and advice