Arm cable resistance

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Clive
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Location: Cheshire, England

#1 Arm cable resistance

Post by Clive »

I've re-wired my Terminator wand with screened silver wire. I use a London (Decca) cartridge, these are prone to hum so I need screened wire. I take the arm cable with no breaks directly to the phono stage. Originally I had 1.5m of wire, I found the sound was flat in comparison to a short arm cable with a 1m interconnect. I've now shortened the arm wire to 1m and sound is back to being really good. The wire is about 30pF per foot, maybe this is one aspect - the cartridge is supposed to need 220pF.

Now for the question: the very thin internal wire measures 5R over 1m. I could find a way to place my phono stage beside my deck so that the arm cable would probably measure 3R. I may end up with too bright a sound due to reducing capacitance but I can add capacitance. Given that the coils in the London (Decca) are 2k ohms should I worry about reducing the cable resistance from 5R to 3R? Is this likely to improve dynamics?

BTW a short arm cable + 1m of interconnect measure around 2R, so that's the best I can achieve but this includes connectors I want to banish.

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Nick
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#2

Post by Nick »

Personally I doubt it, what load is it driving into?

Then again, I can't explain why removing a foot of cable would make any difference either.
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Andrew
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#3

Post by Andrew »

I don't think there's an easy answer to this one Clive, apart perhaps, from the one you have identified , get the phono as close to the deck as possible.

I agree, connectors are generally a bad thing, but in this case, could they be a necessary evil :?:
Clive
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Location: Cheshire, England

#4

Post by Clive »

Thanks Nick and Andrew, the load is 47k so again a couple of ohms should be immaterial. I agree loosing 30pF to 50pF shouldn't have made a big difference.

As for the connectors....there a 2, one from the wand, then some wire to a pair of phonos. I've tried a couple of i/cs from the arm phonos, neither is quite right whereas using the arm wire all the way to phono stage seems to be the best of all.

I've got a hankering to shorten the arm wire further but I find the current length of wire more convenient for the placement of the phono stage. I don't like the idea of a 5R wire really but 3R isn't that much better I suppose.
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