Tonearm re-wire help needed

[HighFidelityGuy]

Hi,

I've been gradually repairing/restoring my PL-71 over the last few months and the other day I started checking over the tonearm. I noticed that one of the bearings that the arm pivots up and down on had collapsed. To get a good look at the problem I had to dismantle quite a lot of the arm. So I thought that while it was in bits i might as well look at re-wiring it. The bearing is repairable by the way.

I want to do the work my self to save money and learn something new.
After looking into a few different options I decided to buy some of this wire:

http://www.hificollective.co.uk/images/silver_coax3l.gif

It's from HiFi Collective and seemed a reasonable price plus I liked the idea of using screened cable. It's 4N silver core and 4N silver shield with Teflon outer jacket and is designed for tonearms.

I now have several wiring options but I'm not sure what will be the "best" for me. My current temporary phono stage will be a NAD PP2 which I got on special offer for about £30. This will get me up and running while I build my WD Phono 3. Both of these only have single ended inputs, so I don't need balanced wiring yet but it would be nice to be able to wire the tonearm so that I could use a balance phono stage in the future without having to re-wire again. I don't know if that's possible. :scratch:

So what wiring method do you recommend I use?

Cheers. :)

[Barry]

Hi,

I've been gradually repairing/restoring my PL-71 over the last few months and the other day I started checking over the tonearm. I noticed that one of the bearings that the arm pivots up and down on had collapsed. To get a good look at the problem I had to dismantle quite a lot of the arm. So I thought that while it was in bits i might as well look at re-wiring it. The bearing is repairable by the way.

I want to do the work my self to save money and learn something new.
After looking into a few different options I decided to buy some of this wire:

http://www.hificollective.co.uk/images/silver_coax3l.gif

It's from HiFi Collective and seemed a reasonable price plus I liked the idea of using screened cable. It's 4N silver core and 4N silver shield with Teflon outer jacket and is designed for tonearms.

I now have several wiring options but I'm not sure what will be the "best" for me. My current temporary phono stage will be a NAD PP2 which I got on special offer for about £30. This will get me up and running while I build my WD Phono 3. Both of these only have single ended inputs, so I don't need balanced wiring yet but it would be nice to be able to wire the tonearm so that I could use a balance phono stage in the future without having to re-wire again. I don't know if that's possible. :scratch:

So what wiring method do you recommend I use?

Cheers. :)

From the photo, the cable looks like MCX, the smallest 50 Ohm coaxial cable I know of. Since all cartridges are inherently balanced and all modern arms have their metalwork earthed by a separate wire, that is the socket on the base of the arm is a 5-way device, it doesn't matter if you use coaxial wiring within the arm or not.

If you do use coaxial cable then it is important to make sure that the outer shielding is insulated from the metal arm tube (as is the cable you have bought). I would have thought from the perspective of mass, that it would have been preferable to use four single (silver) wires rather then two coaxial cables.

Regardless of what you use, the system will become unbalanced when you terminate the arm leads with phono plugs for use with your NAD amp. Should you later wish to use a phono amp that has balanced inputs (and I know of only one make that does this), then simply replace the phono plugs with a balanced design; usually XLRs.

Regards

[HighFidelityGuy]

Thanks Barry,

Your description of the earth wiring sounds different to how my PL-71 was wired when I received it. There's an earth wire running from the metal chassis under the platter to the ground binding post. Then there's another thinner one that connects from inside the tonearm to one of the signal grounds on the phono output. :scratch:

So should the chassis earth and tonearm earth both be joined together at the binding post and then the signal grounds kept separate from these?

Cheers. :)

[Barry]

Yes.

The metalwork of the turntable and that of the pickup arm are connected together: either at the turntable or at the arm base. A wire then connects the bonded metalwork to an earth terminal on the back of your preamp.

The return wires (the screening) of the signal leads must be kept separate from the earth wire. All three are effectively connected together within the preamp (but not always). If you do not keep them separate you may create an earth loop and have problems with hum.

Regards

[DSJR]

Why not just get the cardas litz cables that most people like so much ?

A few years ago, a chap hoping to sell into the domestic market sent us some interconnects made up of VERY thin wires, possibly similar to this coax, albeit with a white jacket. Total diameter of each channel wire was around 2mm tops and more like 1mm. The interconnects sounded superb, giving a similar effect to the Mark Grants and not being directional either ;) I forgot who this gent was, as I'd have bought some for myself at the time..

[Barry]

Why not just get the cardas litz cables that most people like so much ?

A few years ago, a chap hoping to sell into the domestic market sent us some interconnects made up of VERY thin wires, possibly similar to this coax, albeit with a white jacket. Total diameter of each channel wire was around 2mm tops and more like 1mm. The interconnects sounded superb, giving a similar effect to the Mark Grants and not being directional either ;) I forgot who this gent was, as I'd have bought some for myself at the time..

What I had in mind was:

http://www.tycoelectronics.com/catalog/minf/en/399?BML=10576,17639 ,

in particular the 0.81mm OD version, though there is a 1.13mm OD version. This has silver plated copper conductors, FEP dielectric and outer jacket. FEP is a copolymer of hexafluoropropylene and tetrafluoroethylene, often mistaken for Teflon and is coloured white.

I have a sample lying around somewhere but I can't find it at the moment, so as to confirm dimensions.

I would still prefer to use two twisted pairs for the internal wiring of the arm. This is from a weight point of view, also I can't see how the cables would negociate the arm bearing.

Regards

[HighFidelityGuy]

Yes.

The metalwork of the turntable and that of the pickup arm are connected together: either at the turntable or at the arm base. A wire then connects the bonded metalwork to an earth terminal on the back of your preamp.

The return wires (the screening) of the signal leads must be kept separate from the earth wire. All three are effectively connected together within the preamp (but not always). If you do not keep them separate you may create an earth loop and have problems with hum.

Regards

Thanks Barry,

Mine's definitely wired up wrong at the moment then. I guess one of the previous owners must have had a go at re-wiring it. It was probably the same person that buggered up the am bearing. :rolleyes: I'll soon sort that out though. :)

So when it comes to the actual signal wires, I should use two runs of wire, one for left, one for right and use the central wires for the signal and the screen for the ground/return? Does that sound right?


Why not just get the cardas litz cables that most people like so much ?

A few years ago, a chap hoping to sell into the domestic market sent us some interconnects made up of VERY thin wires, possibly similar to this coax, albeit with a white jacket. Total diameter of each channel wire was around 2mm tops and more like 1mm. The interconnects sounded superb, giving a similar effect to the Mark Grants and not being directional either ;) I forgot who this gent was, as I'd have bought some for myself at the time..

I've decided to steer clear of using any sort of litz type cables in my system due to their higher capacitance. I use a passive preamp, so I want to keep cable capacitance to an absolute minimum.

I've heard quite a few reports of very thin interconnects working very well. It makes sense if you think about it. Providing you've got just enough conductor for the signal to travel unimpeded and just enough sheathing to stop shorts and protect the cable, that's all you need. High purity silver or copper and a little Teflon. That's why I liked the look of this cable, its minimal. Saying that it's going to be a bugger to solder and I'm really not looking forward to that bit. :(

Cheers. :)

[Barry]

So when it comes to the actual signal wires, I should use two runs of wire, one for left, one for right and use the central wires for the signal and the screen for the ground/return? Does that sound right?

Yes. To complicate matters the cables should be connected as follows:

Left hand channel: inner conductor to the WHITE contact (as it appears in the headshell)

Left hand channel: outer conductor (screen) to the BLUE contact

Right hand channel: inner conductor to the RED contact

Right hand channel: outer conductor (screen) to the GREEN contact.

Regards

[HighFidelityGuy]

Yes. To complicate matters the cables should be connected as follows:

Left hand channel: inner conductor to the WHITE contact (as it appears in the headshell)

Left hand channel: outer conductor (screen) to the BLUE contact

Right hand channel: inner conductor to the RED contact

Right hand channel: outer conductor (screen) to the GREEN contact.

Regards

Awesome, thanks Barry! I'll hopefully get started on this tomorrow. :)

On the subject of cable diameter etc, the cable I got has an overall diameter of 0.6mm and is very light and flexible. So I'll hopefully not be adding any additional mass to the arm.

I'm also thinking about running the tonearm wire all the way to the phono stage to reduce the number of connections in the signal path. I've got some Teflon sheathing I can use to cover the external section to add some extra protection. I'll give it a try and see what happens.

Cheers. :)

[Barry]

Great Dave,

Let us know how you get on.

Regards

[HighFidelityGuy]

Aaarrrgh, I'm not having any luck with this wire.
The sheathing on the internal conductor is stronger than the wires inside. So every time I try and strip it off I end up striping the wires out and leaving the sheathing intact. I couldn't even melt it with the tip of my soldering iron, even when I set it to 380 degrees C which is well above the melting point of Teflon. :scratch: :(

Does anyone have any suggestions for removing the inner sheathing?

Cheers.

[John]

Vic of Trans Fi sells this
http://www.trans-fi.com/tonearmwire.htm

[Clive]

Aaarrrgh, I'm not having any luck with this wire.
The sheathing on the internal conductor is stronger than the wires inside. So every time I try and strip it off I end up striping the wires out and leaving the sheathing intact. I couldn't even melt it with the tip of my soldering iron, even when I set it to 380 degrees C which is well above the melting point of Teflon. :scratch: :(

Does anyone have any suggestions for removing the inner sheathing?

Cheers.
I use the same wire. The internal white sheath I find melts with the soldering iron set to mid temp, but it does need a blob of solder on it. I have used another method. Using a gas burner on our cooker I very rapidly poke the wire into the flame, this vapourises the teflon but does not melt the silver wire.

If you are running a long piece of this wire be advised that you'll have a resistance of 5R or so for a 3ft run. For the 2k coils on my cartridge this is fine, whether this is ok with eg a 10R MC I don't know.

[HighFidelityGuy]

Vic of Trans Fi sells this
http://www.trans-fi.com/tonearmwire.htm

Thanks John but I'm trying to avoid using litz wire if possible. However I did find the soldering advice on that site interesting. Especially the bit about pinching the sheathing between some fine emery paper. I've just tried this and it seems to work much better than my previous attempts, so I'm going to give that a go.


I use the same wire. The internal white sheath I find melts with the soldering iron set to mid temp, but it does need a blob of solder on it. I have used another method. Using a gas burner on our cooker I very rapidly poke the wire into the flame, this vapourises the teflon but does not melt the silver wire.

If you are running a long piece of this wire be advised that you'll have a resistance of 5R or so for a 3ft run. For the 2k coils on my cartridge this is fine, whether this is ok with eg a 10R MC I don't know.

Thanks Clive, I hadn't thought about the length affecting the cartridge loading. I'm going to be using a MM for now, specifically an AT120e. So hopefully this won't cause any problems.
The gas burner is a good idea. I have a mini blow torch that reaches 1300 degrees C, so a very quick blast with that may do the trick. I'll try that if the emery paper doesn't work out.

Thanks for the suggestions! :)

[Clive]

Thanks Clive, I hadn't thought about the length affecting the cartridge loading. I'm going to be using a MM for now, specifically an AT120e. So hopefully this won't cause any problems.
The gas burner is a good idea. I have a mini blow torch that reaches 1300 degrees C, so a very quick blast with that may do the trick. I'll try that if the emery paper doesn't work out.

Thanks for the suggestions! :)

I've made 3 sets of cable with 4n, all have been done with one of the heating methods, I feel the emery paper method is good for burnt insulation on litz but with 4n there is the risk you'll damage the wire. But with trial and error you may find it works for you.

Re wire length, I wasn't thinking so much about loading, more the effect 5R has on the sound, this can hit bass performance but with an MM you are likely to be fine as the coil resistance will be high and the load 47K. With an MC of 5R or 10R feeding into 100R I worry there would be a problem as it would be like doubling the coil resistance.

BTW, I run a 3ft length directly to my phono stage. It sounds great, it needed a few hours burn in to calm down the high frequencies. The capacitance is low so I had to add some polystyrene caps to my phono stage input.

[HighFidelityGuy]

I've made 3 sets of cable with 4n, all have been done with one of the heating methods, I feel the emery paper method is good for burnt insulation on litz but with 4n there is the risk you'll damage the wire. But with trial and error you may find it works for you.

Re wire length, I wasn't thinking so much about loading, more the effect 5R has on the sound, this can hit bass performance but with an MM you are likely to be fine as the coil resistance will be high and the load 47K. With an MC of 5R or 10R feeding into 100R I worry there would be a problem as it would be like doubling the coil resistance.

BTW, I run a 3ft length directly to my phono stage. It sounds great, it needed a few hours burn in to calm down the high frequencies. The capacitance is low so I had to add some polystyrene caps to my phono stage input.

Thanks Clive, I understand what you mean now. I'm new to all this stuff so it's a steep learning curve. I also wasn't aware that too little capacitance could be an issue. How could you tell that you had too little and how did you know how much extra to add?

Many thanks. :)

[Clive]

Thanks Clive, I understand what you mean now. I'm new to all this stuff so it's a steep learning curve. I also wasn't aware that too little capacitance could be an issue. How could you tell that you had too little and how did you know how much extra to add?

Many thanks. :)
To clarify further about the resistance of the wire....loading is in parallel to the cartridge coils where as wire resistance is in series with it so I expect the effects will differ.

Too little capacitance will give a dull sound, too much capacitance will be bright. Your cartridge specs will state the optimal capacitance, this is only a guide. You'll probably need to be in the range of 100pF to 300pF. It helps to measure the capacitance of the wire and also know whether your phono stage has capacitors installed already. Ultimately if you need to tune capacitance you do this by ear.

[The Grand Wazoo]

A word of caution folks:

Do not breath the fumes of melting teflon.
They are extremely toxic

The slightest whiff will give you a crushing headache - more prolonged exposure is much, much worse.

[HighFidelityGuy]

A word of caution folks:

Do not breath the fumes of melting teflon.
They are extremely toxic

The slightest whiff will give you a crushing headache - more prolonged exposure is much, much worse.

:eek: Thanks for the warning! I had no idea.

[Clive]

Interesting about fumes from Teflon. It looking like teflon coated cookware isn't such a good idea. However I recommend used the gas flame method for melting the wire sheath, it'll be easier to avoid fumes this way than it would when using a soldering iron.

[Barry]

Do not breath the fumes of melting teflon.
They are extremely toxic

Yes indeed, thanks for the warning Chris. I had spotted HighFidelityGuy's post and was going to respond with a similar cautionary post but got side-tracked by writing a very lengthy post elsewhere.

Clive, I have found that careful use of a sharp scalpel blade is all you need to 'strip' Teflon insulation. Wire strippers are usually ineffective because Teflon is too slippery.


Too little capacitance will give a dull sound, too much capacitance will be bright. Your cartridge specs will state the optimal capacitance, this is only a guide. You'll probably need to be in the range of 100pF to 300pF. It helps to measure the capacitance of the wire and also know whether your phono stage has capacitors installed already. Ultimately if you need to tune capacitance you do this by ear.

I would have thought it was the other way round? Either way, be guided by the cartridge specs and let your ear be the final arbiter.

Regards

[Clive]

Do not breath the fumes of melting teflon.
They are extremely toxic

Yes indeed, thanks for the warning Chris. I had spotted HighFidelityGuy's post and was going to respond with a similar cautionary post but got side-tracked by writing a very lengthy post elsewhere.

Clive, I have found that careful use of a sharp scalpel blade is all you need to 'strip' Teflon insulation. Wire strippers are usually ineffective because Teflon is too slippery.



I would have thought it was the other way round? Either way, be guided by the cartridge specs and let your ear be the final arbiter.

Regards
I was trying to remember which way round it is! Trouble is you do this once and then forget about it. Thinking about the values, it's the resistive loading that when reduced dulls the treble. Probably capacitance is the other way around....

A scalpel is not likely to work with the inner wire we have here. You would not believe how thin it is, way thinner than a human hair. The slightest nick will cut it.

[The Grand Wazoo]

There's a thing called 'Polymer Fume Fever' or 'Polymer Flu' which is supposed to be like a bad case of flu. A bad case can cause permanent lung damage - this is how people are affected but birds can be directly killed by the fumes.

The trouble with teflon apparently is that once it enters your body, through whatever pathway, that's where it stays.

[DSJR]

I was trying to remember which way round it is! Trouble is you do this once and then forget about it. Thinking about the values, it's the resistive loading that when reduced dulls the treble. Probably capacitance is the other way around....

A scalpel is not likely to work with the inner wire we have here. You would not believe how thin it is, way thinner than a human hair. The slightest nick will cut it.


Capacitance can sometimes be used to flatten the treble suckout of some mm designs, after which the response plummets, many cartridges having no more output above 20KHz or so than CD does....

I do wish that some phono stages had a means of adjusting the load *impedance* though, as this has a far more beneficial effect on some designs with a smoothly rolling-away treble. Reducing the load reduces the treble response a bit and vice versa IIRC.

back in the days of measurements, this was discussed in reviews, as these people could work out the final response by using the cartridge coil resistance and inductance when working into various loads. sadly, we don't have this info available now, so we have to resort to the worst devices for such things, our ears and brain, which change in perception on a minutely and hourly basis, let alone daily or weekly..:lolsign:

[Marco]

Mine don't. As I am a super-duper wonder being, my ears are thus ultra super-duper, peachy-keen and mega-accurate 24-7, 365 days a year :cool:

:lolsign:

Marco.

[DSJR]

I bet that's not all that's on form every day, 365 days a year either... :eek: :youtheman: :p

[Barry]

I was trying to remember which way round it is! Trouble is you do this once and then forget about it. Thinking about the values, it's the resistive loading that when reduced dulls the treble. Probably capacitance is the other way around....

A scalpel is not likely to work with the inner wire we have here. You would not believe how thin it is, way thinner than a human hair. The slightest nick will cut it.

Clive,

How about one of these?

http://uk.rs-online.com/web/search/searchBrowseAction.html?method=browseSubRange&Ne=4294953839&N=4294946730&productNum=0662737

I used to use them at work to strip PTFE coated wires that are used for wire wrapping.

Regards

[Clive]

Clive,

How about one of these?

http://uk.rs-online.com/web/search/searchBrowseAction.html?method=browseSubRange&Ne=4294953839&N=4294946730&productNum=0662737

I used to use them at work to strip PTFE coated wires that are used for wire wrapping.

Regards
That might work though a friend has something similar, his were fine with the outer sheath but for the inner they wouldn't work reliably, they usually took the wire.

[The Grand Wazoo]

I'd be going back to your supplier & asking them how they suggest you strip the wire. If they can't suggest something that works properly, then I'd be asking for my cash back - whether I'd wasted some of it or not.

[Clive]

I'd be going back to your supplier & asking them how they suggest you strip the wire. If they can't suggest something that works properly, then I'd be asking for my cash back - whether I'd wasted some of it or not.
The wire comes from Nick Lucas (hificollective). I know what he does, it's the same as I do, he melts it with a soldering iron. The wire is kind of special, sounds great, is not particularly expensive and it kills any hum stone dead, even with my London (Decca) cartridges, which is no mean feat.

[Barry]

The wire comes from Nick Lucas (hificollective). I know what he does, it's the same as I do, he melts it with a soldering iron. The wire is kind of special, sounds great, is not particularly expensive and it kills any hum stone dead, even with my London (Decca) cartridges, which is no mean feat.

If you can do that, then the isulation is unlikely to be PTFE (Teflon). Unless his soldering iron is set to be hotter than 327 degC! This is very high even for silver loaded solder.

It also carries the risk of inhilation of toxic fumes, which can cause permenant damage to you lungs. Do not underestimate the danger.

Regards

[HighFidelityGuy]

As I mentioned before, I even tried setting my soldering iron to 380 deg C but that just melted it a bit. I couldn't get it to burn or shrivel up much until I left the iron on it for ages. The emery paper didn't work very well in the end either. It just cut the sheathing into lots of tiny ribbons that were indistinguishable from the conductors. It does remove the outer sheathing quite well though.

I'm going to try a quick blast with my mini blow torch tomorrow. That can do 1300 deg C, so if that doesn't shift it I'll be asking for a refund. Or perhaps I'll leave it in my car in case I need a tow rope. I'll make sure to wear a respirator while doing the blow torching to be on the safe side.

Cheers.

[Clive]

If you can do that, then the isulation is unlikely to be PTFE (Teflon). Unless his soldering iron is set to be hotter than 327 degC! This is very high even for silver loaded solder.

It also carries the risk of inhilation of toxic fumes, which can cause permenant damage to you lungs. Do not underestimate the danger.

Regards
I have an Antex TCS soldering iron, its temp tange is 200C to 450C. I use it generally with the temp control set 2/3rd the way round, who knows what temp this is but it's what I find works well with lead free solder. All I do is turn the iron up a little and it melts the teflon.

Re the danger, now that I know about I'll make sure I don't inhale, I appreciate small amounts will be dangerous.

[HighFidelityGuy]

It seems the inner sheathing isn't indestructible as the blow torch is doing the trick. I just have to flick the wire through the flame and it shrivels up nicely. It's still tricky but I'm getting the hang of working with this wire now, so I'm finally starting to make some progress.

My WBT Nextgen AG's have just arrived too. :eyebrows:

[Clive]

Hi Dave,

Glad it's working out for you now, when you complete the wiring give it a few hours to balance out the frequencies, it'll be quite toppy to begin with.

Cheers,

Clive

[HighFidelityGuy]

Well I think I've got it sorted. All the wires are soldered on at the cartridge end and I've re-built the arm. Now I just need to finish refurb'ing the rest of the deck. I've got the whole thing in bits. I'm even re-finishing the wood. It's taking ages but I'm sure it will be worth it in the end. :)

Thanks for the help everyone! :)

[The Grand Wazoo]

Well done Dave!
You can breathe again now