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Old 7th Jan 2010, 1:05 am   #1
12345678
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Default Series cartridge wiring, please help

Hi Folks,

A little while back I wrote about my problem with sticking and jumping and my Garrard 50 player. I suspected it was a problem with the cartridge and since buying a new type SC12H I no longer have any jumping BUT... Since wiring the cartridge in I have quite vastly reduced volume and a distinct lack of bass. Now I am really not technical so I need a very basic guide as how to rewire in series. At the moment the wires I have in are the red and white are pushed into the plus and the blue and green into the minus. What do I need to push where to make thi wired in series? Any help much appreciated.

Kit
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Old 7th Jan 2010, 1:51 am   #2
Tim
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Default Re: Series cartridge wiring, please help

Sounds as though you might have them out of phase and are only picking up the differerence between the stereo channels. Try a mono record( if you have one), and you won't get anything-or hardly anything, if I am correct.
When using a stereo cartridge on a mono player, two diagonal pins on the back of the cartridge are often found linked (but not earthed) and the signal taken from the opposite diagonals. You can create a link at the amplifier end by using the appropriate wires.
Try reversing ONE pair and see what happens. You can see which wire is earth and which ones are signal at the amplifier end.
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Old 7th Jan 2010, 12:40 pm   #3
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Default Re: Series cartridge wiring, please help

Usually on a Garrard deck, the red and green wires are the the right hand channel, and the black and white wires the left, so it sounds as though you have connected wrong ones.Connect the red to the pin marked R+ and the green to R-.You should now have full sound, but with only the right hand channel connected. If this is ok, let us know, and we can tell you then how to connect the two channels together.

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Old 7th Jan 2010, 12:47 pm   #4
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Default Re: Series cartridge wiring, please help

Yes, the standard wiring code for cartridges these days is red = right hand channel positive ; green is right hand channel negative ; white is left hand channel positive and blue is left hand channel negative, so your cartridge is wired up wrong.
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Old 7th Jan 2010, 5:38 pm   #5
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Default Re: Series cartridge wiring, please help

Does series wiring really make that much of a difference?

It's my understanding that Rochelle salt crystals put out a higher voltage into an open circuit than artificial ceramics, but also have a higher Thévenin impedance; and even with a 500kΩ or 1MΩ volume control, some of that voltage simply never makes it as far as the terminals, but gets swallowed up by the internal impedance. A ceramic cartridge with the two channels in parallel has a quarter of the Thévenin impedance of the same cartridge with the channels in series, so more of that (lower) voltage will appear across the gain control.

My own experiment has shown that feeding a crystal cartridge into an oscilloscope and switching the probe from 10:1 (Zin = 10MΩ) to 1:1 (Zin = 1MΩ) barely makes the trace much bigger, and certainly does not produce the tenfold difference one might naïvely expect!
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Old 7th Jan 2010, 11:22 pm   #6
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Default Re: Series cartridge wiring, please help

ok here goes.

I have had to experiment a lot because the cartridge that I did have was an old 2 pin Garrard, now the only wires plugged into that were the blue and white. I have now plugged them into the right hand terminal and have a good strong sound. Bass is ok but over all plenty of power apart from a distinct treble sound that is quite harsh. Somebody mentioned another step? Do I need to put some wire between the other two terminals or something.

Thabkyou all for your help so far.

Kit
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Old 7th Jan 2010, 11:24 pm   #7
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Default Re: Series cartridge wiring, please help

Hi,

I have wired up but the only way I can get this working is with the white and red wire in the right and channel of the cartridge. Let me know the next step please and thanks so much

Kit
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Old 8th Jan 2010, 12:18 am   #8
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Default Re: Series cartridge wiring, please help

Try red to RH+ and white to LH- and then link across the two remaining terminals ie RH- and LH+.
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Old 8th Jan 2010, 12:24 am   #9
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Default Re: Series cartridge wiring, please help

Have a look at the crude sketch in post #8 of this thread. The series wiring shown is actually the reverse of what I've described above but you'll get the idea nonetheless.
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Old 8th Jan 2010, 12:44 am   #10
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Default Re: Series cartridge wiring, please help

Hi Darren,

Thanks for your reply. When you say link do you mean simply place a piece of wire between the RH- AND LH+ ? Will any thin wire do?

Thanks,

Kit
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Old 8th Jan 2010, 12:49 am   #11
Audio1950
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Default Re: Series cartridge wiring, please help

If your'e getting a good sound on one channel with the blue and white, it means the amp has been connected to these two, instead of the red and green, which is the usual way. The red SHOULD be the "positive" of the spare two and be connected to the spare "+" pin on the cartridge, and the green to the spare "-" pin. Someone may have mucked about with this in the past, though, and connected it wrongly. However, you can't do any damage by experimenting, so if the above doesn't work, try swapping the red and green over. If you get good sound, you need to remove the deck, and connect the two wires which are not connected to each other. You will see that two of the wires are connected together across a terminal strip, which is screwed to the underside of the deck. These are the "earth" or negative wires and should be left alone. You need to join together the other two, which are the "signal" or "positive". Incidentally, it would tell you instantly which wires go where on the cartridge if you took the deck out and had a look first. Whichever wires are joined at and across the centre of the terminal strip, those colours go to the -pins of the cartridge. Doesn't matter which, because they are joined. The other two go to the + pins of the cartridge. When you have bridged the two wires under the deck, as above, it should all work perfectly, but if not, try swapping the two + wires over on the cartridge. I think this actually means the cartridge will be wired in parallel, rather than series, though, so hope I haven't confused the issue.
Barry

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Last edited by Audio1950; 8th Jan 2010 at 12:58 am.
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