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DrNomis_44
06-02-2018, 11:33 AM
Hi Everyone,

Since I'm making some XLR to XLR leads for a good mate of mine and I'm going to be doing some repair work on some of my own leads today, I thought that it would be a good excuse for me to do a mini-tutorial thread about making your own DIY instrument leads, and show you how I go about making them.

I'm going to be documenting the process with some pics as well as a write up.

To start the ball rolling, here's a quick re-cap of the four steps for preparing the leads prior to soldering the plugs onto them, they are:


1, Cut.....Cut the cable to the required length.

2, Strip...Strip the plastic insulation off the cable and the inner-conductors.

3, Twist...Twist the individual strands of shielding braid together so that it forms one neat bundle, do the same for the strands of the inner conductors.

And finally....

4, Tin.....Tin the neat bundles of strands by coating them with solder, they should look shiny once you're done.


I will be going into each step in more detail and adding pics soon so stay tuned....

JohnH
06-02-2018, 11:40 AM
Good idea for a thread Doc, I reckon there’s more than a few people on the forum who’d be interested to try this.

Marcel
06-02-2018, 02:27 PM
Many prefer to 'tin' the lead ends before taking them to the plug/socket to be soldered on to the pins. This does make the actual soldering a lot easier and often makes for a more reliable solder joint.

For myself I prefer to fit the wire into its intended final location on the pin first, and then apply/use solder to secure the joint. On a TRS or TS plug this allows me to put the wire neatly through the tiny hole to give added mechanical strength to the final joint, and on a XLR allows me to ensure the wire is fully inside the cup at the end of the pin before solder is applied. Down side is if the wire is at all dirty or has any corrosion there is limited scope to correct any 'wetting' issues should they arise, and often may require a full clean and start from the beginning again to rectify those issues.

DrNomis_44
06-02-2018, 02:45 PM
Yep, there's lots of ways to do it, if I'm making up an XLR-XLR lead, or a TS-TS, or TRS-TRS lead, I like to tin the wire and connections separately and then let the solder do all the work for me when I go to solder the connections together, definitely insures a good reliable joint, I'm just going to have something to eat first before continuing on with the mini-tutorial.


When you're doing the actual soldering, there's three rules to observe in order to get a good solder-joint, they are:


1, Cleanliness.

2, Cleanliness.

and....

3, Cleanliness.


Expanding on that....you want to make sure that the tip of your soldering-iron is clean and shiny, if you're working with a soldering-iron that has a dirty, and, or, rusty tip, you're not going to get joints which are shiny and have wetted the two surfaces to be soldered together, you also want to make sure that the surfaces being soldered together are clean and shiny, trying to solder to a dirty surface will not produce a good and reliable solder joint.

DrNomis_44
06-02-2018, 03:38 PM
Rightio, before we start making some DIY instrument leads, we need to get together the raw materials, soldering iron, or soldering station, solder, and some tools, and then set everything up on a convenient workspace.


Materials:

Cable, Jaycar Electronics sell two different types of cable that I have used to make instrument leads, one type has a single core and shield surrounding it, the Jaycar Electronics catalogue number is WB-1508, it is roughly 6.5mm in diameter and has a black outer plastic-sheathing, the other type has two inner cores surrounded by a shield, the Jaycar Electronics catalogue number is WB-1530 has a black outer plastic shrouding too, I mostly tend to use the WB-1530 cable, here's a comparison pic to show what they look like, the top one is the WB-1508 cable:

24644


Plugs, there's two types of plugs I tend to use when I make my DIY instrument cables, there's a metal right-angle plug, and a straight one, here's a pic so you can see what they look like:

24645


Both are stocked by Jaycar Electronics and I've found them to be pretty reliable.

https://www.jaycar.com.au/6-5mm-pro-metal-mono-plug/p/PP0157

https://www.jaycar.com.au/6-5mm-pro-phono-right-angle-plug/p/PP0159

Simon Barden
06-02-2018, 03:39 PM
I expand any too-small holes in order to get the wire through them. I really don't like just using solder to fix wire to metal, though sometimes, like with pots, there's no other choice.

When I started off soldering I was told that a good mechanical connection males for a good solder joint, and I've stuck to that wherever possible; putting the wire through any holes then wrapping the wire back and around so that it can stand at least a gentle tug on its own before applying the solder.

Sometimes I find it easiest to strip more of the wire than necessary just so I can tin just the very tip, then if it's a bit wide, cut the end down a bit with wire cutters so that it's easy to fit through the hole without some strands failing to pass through and producing messy whiskers. Then do the wrapping part and cut off any excess wire (including the tinned tip).

DrNomis_44
06-02-2018, 03:47 PM
Good point Simon, yes whenever possible try to make the solder-joint as mechanically strong as possible, solder is a relatively soft material and while it is electrically strong, it's not very mechanically strong.


Okay, so I've covered the materials that I use to make my DIY instrument cables, next are the tools that I use.


Here's a pic of my Temperature-Controlled Soldering Station, I'd highly recommend getting a temperature controlled station because it makes things a lot easier when it comes to getting good solder joints, definitely worth the money:

24646


Here's a pic of a device that's sometimes called a Third Hand, very useful for holding things together while you're soldering:

24647

Next up is a pic of the roll of 60/40 Resin-Cored solder that I use, it's about 1mm in diameter, some people like to use Lead-Free solder:

24648

Here's a pic of a container of Solder Flux, this is always very handy to have because it helps the solder to take to the metal surfaces being soldered:

24650


Here's a pic of one of my rolls of 3mm Goot Solder Wick, this is a special chemically treated braid that soaks up excess solder, much like a sponge soaks up water, definitely handy to have if you ever need to de-solder a solder joint, better still make sure you have at least two:

24649

DrNomis_44
06-02-2018, 04:34 PM
Next is a set of various pliers, and a clipper, these are handy because sometimes you may need to bend something into shape:

24651

Here's a pic of my two Digital Multimeters, very useful when it comes to doing some tests on your new DIY instrument lead to see if it is going to work properly, or for troubleshooting it if it doesn't work:

24652


Both of my multimeters feature a Continuity Test function that produces an audible beeping-sound, when a lead is being tested for continuity between say the two tip-connections, and an audible beep is heard, that means that there is no break in the wire conductor running from the tip of one plug to the other, that also indicates that the lead is good, that's assuming that the sleeve connections also give an audible beep when tested, note that there should not be any audible beep when testing from the tip to sleeve on either end of the cable

Next is my wire stripping tool, this is used to strip the insulation off the inner cores of the cable prior to tinning and soldering:

24653


Sometimes you might come across a plug that uses screws to hold wires in place on connections, some XLR plugs use screws to hold them together, so it's good to have a few screwdrivers in amongst your collection of tools, some thin Philips-Head and Flat Heads of various sizes should be included.

DrNomis_44
06-02-2018, 05:01 PM
I'm going to be continuing on with a discussion on how I actually go about making my DIY instrument leads soon.....stay tuned.

Marcel
06-02-2018, 06:54 PM
Something I'd like to throw in at this point is about the two types of solder -- 60/40 Lead/Tin type and the RoHS compliant Lead free solders...They are not compatible and it is best to not mix the two. In essence a Lead free designated iron must only be used on Lead Free joints with Lead free solder, and Tin/Lead solder only on Tin/Lead joints with a iron designated for Tin/Lead soldering. Mixing the two different solder types will contaminate the solder resulting in far more frequent 'cold joints' and reduced reliability and strength of the soldered joint.

FYI - The whole 'Lead free' thing was initiated by a huge bunch of nations to reduce the amount of Lead in our environment. In itself the reduction of Lead in our environment is a good thing as like the liquid metal Mercury the Lead once ingested into our bodies is toxic and can cause/create a whole army of health problems with few available corrective measures. To identify all the Lead reduced products the "RoHS compliant" scheme was created. After much protest and subsequent expensive R&D the electronics industry came up with the current series of formulae for 'Lead free' solders, but it has its problems with the two major ones being incomparability with Tin/Lead solder and that it needs a relatively much higher temperature than Tin/Lead solder to melt (typically being around 190C/360F for 60/40 Tin/Lead and 210-220C/410-430F for (Sn-Ag-Cu-Mn)(Sn-Ag-Cu-Zn) RoHS Lead free electronics solder).

For more info https://en.wikipedia.org/wiki/Solder is a great resource...

Both work and do work well.... just if at all possible don't mix and switch your irons between the two...

As a side note the whole RoHS lead free thing is probably why we have seen such a huge reduction in the amount of Germanium solid state devices on the market as Germanium devices are very sensitive to the heat from soldering.... A RoHS compliant Germanium based device is a rare item to discover...

Simon Barden
06-02-2018, 07:45 PM
And don't try to heat your geraniums up to 190°C either, they won't like it. ;)

DrNomis_44
06-02-2018, 08:27 PM
And don't try to heat your geraniums up to 190°C either, they won't like it. ;)



That's right, flowers are very sensitive to heat and we must treat them with the respect they deserve....hahahaha.


Sorry, couldn't resist so I had to throw that one in, but I was trying to be un-biased at the same time....you know how it is....okay I'll stop while I'm ahead....lol.

Now, here's a thought to meditate on.....how best to properly bias a flower?, my first thought is to add equal parts of fertilizer, sunshine, and water, and then see what happens.....um.....eh....er......ah....*scratches head*.....

corsair
07-02-2018, 05:14 AM
When I started off soldering I was told that a good mechanical connection males for a good solder joint, and I've stuck to that wherever possible; putting the wire through any holes then wrapping the wire back and around so that it can stand at least a gentle tug on its own before applying the solder.

See, the TV repairman who taught me to solder was of the opinion that a good soldered join didn't need a mechanical join to be strong; as long as there wasn't too much tension on the soldered joins... like the tension in an instrument cable! I mean, we've all tried pulling a soldered join to bits, haven't we? They're pretty damn strong mechanically as well as electrically!
I've always just soldered onto whatever tags/cups/ears that were and have never had a mechanical failure that I haven't caused by treading on the cable, which is going to cause a problem regardless of the type of soldered join employed!

Of course, YMMV....

DrNomis_44
07-02-2018, 11:01 AM
Rightio, it's all well and good to have a quick discussion on the materials and tools I use to make my DIY instrument leads, but you guys are probably more interested in how I actually go about making them....right?


Okay then, lets get started....


First thing I do is decide how long I'm going to make the instrument lead, I tend to go by the rule of thumb that states that it is always easier to shorten a piece of wire than to lengthen it, so, I always try to make it a bit longer than I really need it to be, although sometimes I have to work with whatever piece of cable is available, in this case I've got two pieces of Jaycar WB-1530 cable that I'm going to be using to make two leads, they are not that long, about a couple of metres or so, it doesn't really matter cause I can use them as patch leads for my pedals, the only proviso is that they work perfectly when finished.

Since the cable is already cut to length, the next thing to do is to strip the black plastic insulation off each of the ends of the cable so that I can solder the plugs onto the inner conductors and shielding braid, solder doesn't really take very well to the plastic, as I go through the process of making the lead I'll post pics so you can see what it should look like for each of the steps.


Here's a pic of the Jaycar WB-1530 cable I'm using with the insulation on both ends stripped off to about 20mm:

24661


After doing that to both ends of the cable, I pushed the braid back against the remaining insulation so that it loosely bunched-up:

24662

24663


The next thing I did was to use the tip of one of my multimeter probes to make an opening in the braid so that I could pull the inner cores through it:

24664

DrNomis_44
07-02-2018, 11:53 AM
After making the hole in the braid, I carefully pulled the two inner cores and the white cotton fibers through it:

24665

After pulling the two inner cores and the white cotton fibers through the hole i made in the braiding, this is what I was left with:

24666


I did the same to the other end of the cabling to complete the preparation of the cable prior to soldering on the plugs.

DrNomis_44
07-02-2018, 12:17 PM
You can see in the last pic I posted that the braid has been straightened-out, that's just to keep it nice and neat when I tin it prior to soldering the plug on.


Next thing I did was to trim-off the white cotton fibers so that they wouldn't get burnt by the soldering iron, that also stops them getting in the way too.


The next step is to trim the braid and the two inner cores to length and strip about 5mm of insulation off both of them.

Trimmed to length:

24668

Inner Cores stripped:

24667

Inner Cores twisted together:

24669

Core and braid tinned, ready for soldering to the plug:

24670

DrNomis_44
07-02-2018, 01:18 PM
Next thing I did was to put the rubber boot and black plastic cable-clamp on the cable before soldering the cable to the plug:

24671


If the plugs that you're using to make your instrument lead have rubber boots on them, make sure they go on first, nothing's worse than having to de-solder a plug because you forgot to put the boot on first, I know cause I've done it a few times myself.

Next, I trimmed the tinned braid back a bit, the cable is then ready to be soldered to the plug:

24672


And finally I soldered the braid to the sleeve connection on the plug, and then the two inner cores to the tip connection, making sure I didn't inadvertently create unwanted short-circuits in the process, the plug had already been pre-tinned so it made things a lot easier for me:

24673


Once I had got all the soldering done, I repeated the same procedure to solder a plug on the other end of the cable, I then used my multimeter to check that there was continuity between the two sleeves of the plugs, continuity between the tips of the two plugs, and no continuity between the tip/sleeves of the two plugs, the newly-made instrument lead passed all the tests so it's a good one that's ready for use and should work perfect.


That's basically how I go about making my own DIY instrument leads.

Marcel
07-02-2018, 02:32 PM
For those wondering why the Cotton is there and why that we just cut it off flush - The Cotton is just filler to help the overall cable maintain its circular shape. It also helps in minimising scuffing of the centre wires when the cable is flexed during use. In the connector it serves nil purpose so can safely be removed.

Guvna19
07-02-2018, 03:39 PM
Great thread Doc, and all the input from the members!

going to be a down the track project for me.

thanks Guv

Simon Barden
07-02-2018, 03:45 PM
For those that haven't done it before, a quick explanation of how you strip the external insulation off the cable first would be good.

DrNomis_44
07-02-2018, 07:04 PM
Ah....sorry about that oversight, I blame that on me not having fully woken up due to insufficient coffee in me.

Simon Barden
07-02-2018, 07:24 PM
It's easy to overlook as you already know how and it isn't hard - but for a comprehensive guide it needs to be there.

DrNomis_44
07-02-2018, 08:56 PM
(Addendum):

To strip the insulation off the Jaycar WB-1530 cable I'm using to make the new DIY Instrument lead, I measured roughly about 20mm from the end and used the thumbnail on my left-hand thumb to put a slight nick in the insulation, after doing that I bent the cable back on itself where the nick was and then used a craft knife to carefully cut through black plastic sheathing of the cable, making sure not to nick any of the strands of the braiding, bending the cable back on itself helps to avoid nicking the braid underneath the outer sheathing.

Here's what the cable looked like after making a nick in the outer-sheathing with my thumbnail:

24679

Here's what the cable looked like after bending it back on itself where the thumbnail nick was placed:

24680

While holding the cable bent back on itself in my fingers, I used the craft knife to cut through the outer-sheathing of the cable, exposing the braid underneath it, while at the same time being very careful not to nick any of the strands of wire in the braiding:

24681


After making the cut in the outer-sheathing with the craft knife, I proceeded to continue cutting the sheathing all around the circumference of the cable till I got back to where I had started from, this enabled the excess sheathing to be easily pulled off the end, exposing the braiding underneath:

24682

DrNomis_44
07-02-2018, 09:01 PM
It's easy to overlook as you already know how and it isn't hard - but for a comprehensive guide it needs to be there.


Sorted....

DrNomis_44
07-02-2018, 09:16 PM
And as a bonus, here's how to test your newly-made DIY Instrument lead with a Digital Multimeter to ensure that it is a good one, note that I'm using a short blue pedal patch-lead for demonstration purposes, if your new DIY Instrument lead passes all of the following tests, then you have a good working lead:


First of all, set your Digital Multimeter to either a low ohms (say 200 Ohms) range setting, or, if your Digital Multimeter has one, the Diode/Continuity Test setting (I've shown it set it to Diode/Continuity Test):

24683

For the first Continuity Test, touch the tip of one multimeter probe to the sleeve of one plug and the tip of the other probe to the sleeve of the other plug as shown in the pic, if you get a low reading and an audible beeping sound, then your lead has passed the first test:

24684


For the second Continuity Test, touch the tip of one of the multimeter probes to the tip of one plug and touch the tip of the other probe to the tip of the other plug as per the pic, if you get a low reading and an audible beeping sound, then your lead has passed the second test:

24685

For the third Continuity Test, touch the tip of one of the multimeter probes to the tip of one plug and touch the tip of the other probe to the sleeve of the other plug as per the pic, if you get a high reading and no audible beeping sound, your lead has passed the third test:

24686


If your lead has passed all three tests then it indicates that you are getting continuity where you should be getting it, from one sleeve to the other, and from one tip to the other, therefore you have a good lead and it is ready for use, if you get different results with any of the above tests then that means something is wrong and it needs fixing.



You can also use an Analog Multimeter to do the three continuity tests on your newly-made DIY Instrument leads, on an Analog Multimeter continuity is indicated by the meter needle moving and then stopping over the zero mark on the meter-scale when set to a low-ohms setting, no continuity is indicated by no needle movement.

Mark Gill
08-02-2018, 01:57 AM
how do you keep it clean, DrNomis..?

DrNomis_44
08-02-2018, 09:25 AM
how do you keep it clean, DrNomis..?


If you're trying to solder a piece of wire to something and it looks a bit dull, you can use some fine grit sandpaper to get it shiny again, you can also use sandpaper to gently clean the tip of the soldering iron but first make sure the soldering iron is switched off, once the tip is clean and shiny, switch the iron back on again, let it heat up to temperature, then apply some solder to the tip, and then wipe the tip on a damp rag or the cleaning sponge provided with the iron.


If you're trying to solder wires onto the solder lugs of a plug, and the solder doesn't want to take to them, you can try sanding the solder lugs a bit with some sandpaper, or, you can use a small needle-file or a Stanley-knife blade, sometimes the plating on the solder lugs of a plug can be a bit iffy, sanding, or scraping the solder lugs till they're shiny can fix it so that the solder more readily takes to the solder lugs.


I tend to make most of my DIY Instrument leads about 5 metres long, although I have made a couple of 10 metre ones in the past, I think 5 metres is about optimum, but there's nothing stopping you from making them longer than that, although you do start running into loss of high-end issues with longer lead-runs, that's one of the reasons why balanced XLR leads started being used in live gigging situations, the balanced XLR leads also reduce a lot of the hum-pickup that can occur with un-balanced instrument leads.

Rabbitz
08-02-2018, 02:44 PM
Arrrrgh, I hate cleaning the soldering iron tip with "a damp cloth" or "a damp sponge".

It's messy, smelly and can damage plated tips with the sudden cooling.

Get yourself down to the supermarket and get hold of one of the gold coloured or stainless steel pot scourers. The ones that look like spirals all balled up. (see here - https://www.woolworths.com.au/shop/productdetails/10924/essentials-stainless-steel-scourer ). That one pack for 89 cents will be a life-time supply.

Bin your damp sponge, place the scourer next to your solder station, when the iron is up to heat, plunge the tip in and out of the scourer once and hey presto, all sparkly clean.

Marcel
08-02-2018, 04:26 PM
Arrrrgh, I hate cleaning the soldering iron tip with "a damp cloth" or "a damp sponge".

It's messy, smelly and can damage plated tips with the sudden cooling.

Get yourself down to the supermarket and get hold of one of the gold coloured or stainless steel pot scourers. The ones that look like spirals all balled up. (see here - https://www.woolworths.com.au/shop/productdetails/10924/essentials-stainless-steel-scourer ). That one pack for 89 cents will be a life-time supply.

Bin your damp sponge, place the scourer next to your solder station, when the iron is up to heat, plunge the tip in and out of the scourer once and hey presto, all sparkly clean.

Must be the iron & damp sponge technique.... I have irons that have tips that are +20yo and one that is almost 40yo and I've only ever used the supplied sponges slightly damped with water ...

Only reason the sponge or scourer is there is wipe away any excess solder.... not for deep scrubbing away any burnt or burning flux...

Simon Barden
08-02-2018, 06:55 PM
I tend to make most of my DIY Instrument leads about 5 metres long, although I have made a couple of 10 metre ones in the past, I think 5 metres is about optimum, but there's nothing stopping you from making them longer than that, although you do start running into loss of high-end issues with longer lead-runs, that's one of the reasons why balanced XLR leads started being used in live gigging situations, the balanced XLR leads also reduce a lot of the hum-pickup that can occur with un-balanced instrument leads.

You are mixing up some very different issues there, Doc.

XLR (or TRS) balanced leads have a similar capacitance level to unbalanced guitar leads - often a bit more - as they are all made of very similar materials and the extra core and insulation increases the capacitance.

In the case of guitars and basses with passive pickups and tone controls, it's the high impedance of the instrument output that makes the effect of the cable capacitance more prominent, as the capacitance forms a low pass filter network along with the output impedance that has a lower and lower cut-off frequency the more capacitance there is i.e. the longer the cable, the more high frequency loss there will be.

This can partly be countered by using cable with extra low capacitance per unit length for longer runs. Some of these cables have half the capacitance per unit length of standard cables, so a 10m long low-capacitance cable will sound similar to a 5m long standard cable in terms of HF loss. A lot of guitars can sound over-bright if you use the very low capacitance cable for short leads, especially when going straight from the guitar into an amp. Of course this may benefit some guitars, whilst on others they may just sound a bit harsh. So it can be used as a creative 'effect'. You just need to understand what's going on.

Pedalboards and cables need a mention, especially if you have a board filled with 'true bypass' pedals. In this instance, with all the pedals in bypass mode, whilst no pedal will affect the guitars tone per se, the guitar cable is now the length of the cable from the guitar to the board, the length of all the patch leads, plus the cable from the board to the amp, which if those lengths are long, is going to affect the straight guitar sound considerably.

Which is why it's a good idea to have at least one 'always buffered' pedal in the chain. A good buffer should be transparent (though not all pedals have good transparent buffers - especially some of the older ones). The audio bandwidth of standard op-amp circuits is way higher than our hearing ability, so you should only be able to hear the effect of a good buffer in a good way. It will provide a high input impedance (normally 1 Meg ohm) for the guitar to 'see', which keeps the guitar's tone normal, and will provide a low output impedance for the signal to the amp (or other pedals) which will remove most of the capacitive effect of the output cable to the amp as the low pass frequency of the cable 'filter' is now above the normal audio bandwidth. So a buffered pedal can drive a far longer output cable than you can get away with with all true-bypass pedals on your board.

For a buffered pedal design, look no further than Boss, as their pedals all have buffers and and have no 'true bypass' switching. Alternatively it's now fairly common for people to have an 'always on' booster pedal like the Xotic EP Booster or TC Spark at or near the start of the FX chain, set for maybe a very slight signal boost. This can both add a 'nice' small EQ tweak to the sound and also act as a signal buffer.

You'll have noticed that most guitars and basses don't have balanced XLR output connections on them (though some with internal pre-amps do and the Les Paul 'Recording' style guitars had transformer balanced low impedance outputs, designed to be plugged directly into a mixing desk). Balanced outputs are generally the province of 'pro audio' equipment i.e. the kit (apart from instruments) that you were once only likely to find in a recording studio or in stage PA equipment (but can now be found in home-studios).

Balanced audio connections are normally more than just 'balanced' (which refers to balanced impedance along the two signal lines and equal impedance to ground), they also operate using opposite polarity signals for better noise rejection.

A guitar lead is an 'unbalanced' connection, not because it uses two wires, but mainly because the shield is directly connected to ground, whilst the signal input has around a 1meg ohm resistance path to ground. There will be a slight connection impedance mismatch because the signal cable impedance will be different to that of the braided outer 'shield' cable.

Simon Barden
08-02-2018, 06:56 PM
A microphone output, once you rise above the cheap 'toy' plastic types and ignoring valve mics, will (these days) normally have a 3-pin XLR connector providing a balanced output signal with a differential output on pins 2 and 3, with pin 1 used for the shield connection. It will feed into a microphone preamp (that may be built into a mixing desk, digital audio interface or a stand-alone mic preamp etc.) that feeds the signals into a differential amplifier.

The mic output signals that have opposite polarity and amplitude to each other. If you fed those signals into a summing amplifier, they would cancel out and you'd hear nothing as a result. That's why they are fed into a differential amplifier, which outputs the difference in the signals, so you get a signal that has twice the amplitude of a single signal. The benefit of this is that any noise picked up by both signal cores won't have any reversed polarity to it, so when it hits the differential amplifier, the noise signals (theoretically) cancel out, and the signal comes out noise free.

Obviously the two signal cores can't occupy the exact same space, so there will be some difference in the noise signals each cable picks up. The nearer the cable is to a source of noise, the greater the difference in the electromagnetic noise field experienced by each core. You only get perfect noise cancellation if the noise levels are exactly the same phase and amplitude, so you can still get some noise in the signal, but at a very much lower amplitude than otherwise.

To increase the ability of the cable to reject noise, the two signal cores are twisted together (the tighter the twist the better), so that there's a better chance of both cables picking up the same amount of noise i.e. with parallel cables, one core is always likely to be nearer the noise source than the other, and so the noise amplitude on each cable is always going to be slightly different. Twisting the signal cores averages out the distance of each cable from a noise source, so it's only when the cable is very near to the noise source that they won't pick up the same amount of noise.

Think of the noise signal as ripples spreading out from the point a stone was dropped in the middle of a lake. Near the noise source/stone impact point itself, you've got very small radius circular waves that are quickly expanding into larger radius waves. If you floated a straight piece of wood in the water on a line perpendicular to the circle radius, the centre of the ripple would noticeably hit one part of the wood first then spread out and hit the rest. But move away 100m and the height of the ripples is now much less and the radius of the ripple waves is now so great that it appears almost flat. The same piece of wood set perpendicular to the radius will now experience the ripple hitting all the wood at almost the same time.

Replace the wood with our twisted pair, and the stone for a noise source. Very near the noise, even though the cable is twisted, one core will be that bit nearer and pick up the noise before the other core does, so there will be a very small amplitude and phase difference in the noise signals picked up.

To increase the noise resistance further, an overall braid shield is added to the cable, which captures a lot of the noise signal and takes it to ground. The better quality cables have a lot more wires/copper in the shield than cheap cables (as copper costs a lot these days). Also the tighter the twist in the signal cables, the more copper you need per unit length of cable. So there's a reason why some cables cost a lot more than others.

Cables for installation that aren't planned to be moved at all after installation will typically have a couple of wraps of aluminised mylar foil sheath with a drain wire around the signal cores instead of a copper braid. This provides more comprehensive protection as there are none of the gaps in the shield that a braid gives you (which let in very short wavelength noise). However, these cables are less flexible than braided shield cables and moving them can cause audible noise as the layers of foil move across each other and cause slight capacitance changes and some static to be produced.

For really noisy environments there's 'star quad' cable, which has two twisted pairs that are also twisted around each other. Each pair carries the same signal i.e. two cores are connected to pin 2 and two are connected to pin 3 on the XLR, but the extra cores and twisting helps the noise levels average out a lot more. Typically used for outside broadcast/live situations where there's a lot of generator power and limited cable route choice so you can't run the audio cables away from power cables etc. The downside is that these cables have a lot more capacitance than a standard mic cable, so whilst you could run a standard 'mic' lead around 100m before the sound starts to suffer, you are at least halving that with star quad.

And what is good for mic cable is also good for connecting other items of audio equipment together. The main benefit of using balanced connections between equipment, especially in the digital age, is that it allows you to break the ground connection provided by the shield at one end of the cable to cure any ground loops whilst the shield still provides its extra noise protection. With unbalanced connections, you can't break the shield, because it’s also acting as a signal carrier.

You don't need an XLR to have a balanced cable you can do exactly the same with TRS jacks. And just because there is an XLR or TRS connection doesn't always mean that the connection is balanced and described as above. A TRS cable used for a stereo signal isn't a balanced cable, even though it is probably exactly the same as a mic cable in every other sense.


But finally, back to guitar leads. The most important cable is the one that you plug into your guitar, so don't go cheap on that one. You don't need to spend a lot to get a good cable, you just need to spend enough, with good jacks and a reputable make of cable in-between them. Don't believe the marketing hype of the mega-expensive brands. I have an £80 (Aus$140) 10 foot boutique brand cable that was included in the case candy when I bought my DG Strat, and it sounds no different to my £20 (Aus$35) cables that have the benefit of Neutrik Silentjacks.

DrNomis_44
08-02-2018, 07:33 PM
Cheers for that Simon, I guess my understanding of Balanced and Unbalanced leads isn't as good as I thought it was, the Balanced system is still a new thing to me.

Marcel
08-02-2018, 08:06 PM
It surprises me that balanced guitar wiring has never really been tried. Technically it is definitely possible and would benefit single coil guitars no end, but I suppose the unbalanced input of every guitar amp on the market means nobody (except me) is willing to give it a try...

One day soon I'll experiment with some TRS leads and a modified el-cheapo strat and possibly my AC18W amp build, and let everyone know how it goes... As a start I'll try with a modified passive DI box right at the amp before getting to excited over the millions of various possible amp balancing modifications.

Derek82
09-02-2018, 04:26 PM
This is a great thread! Thanks all for the info and the laughs!

Sent from my Moto G (5S) Plus using Tapatalk

DrNomis_44
10-02-2018, 11:20 AM
No worries Derek, I had a lot of fun putting the mini-tutorial together, hope it is of some use to all those who want to make their own instrument leads.


I always like to welcome and embrace humor in all the threads I start, let's face it, life can be pretty dull and boring at times so why not brighten it up a bit and have a few laughs while we're at it, we can still maintain some semblance of seriousness at the same time though.

Simon Barden
28-02-2018, 04:08 PM
I've just found this web site with loads of test and background info on different makes of guitar cable. http://www.shootoutguitarcables.com/guitar-cables-explained/capacitance-chart.html

DrNomis_44
28-02-2018, 08:40 PM
Cheers for posting that link for us Simon, needless to say, the capacitance/m spec of each make of cabling is important since the higher capacitance/m spec will translate to more high-end loss that the guitar signal will experience since the capacitance effectively forms a low-pass filter.

Simon Barden
28-02-2018, 08:48 PM
Indeed. But on the other hand, a very short low capacitance lead straight from the guitar to an amp can sound over-bright. Some capacitance and top-end reduction is often wanted.

Plus if you have a pedal that's on, or a buffered pedal, the only capacitance you need worry about is in the lead from the guitar to the pedalboard.

But if you are using a very long lead because you're on a huge stage and want to run about a lot, then certainly go for one of the low very low capacitance cables.

Simon Barden
28-02-2018, 08:53 PM
It was also noted on another forum, that the colour of the lead can make a difference to the capacitance of the lead (different chemical dyes in the plastic having an affect). A studio owner made up two guitar leads, all Neutrik jacks, identical cable manufacture and type apart from the colour - one red and one white. He has someone come in to re-record a guitar part from a previous session in November and wanted to get the same sound. Try as they might, they couldn't get the sound the same. Then someone suggested swapping the lead, so they changed the red one for the white one, and instantly the sound was there again!

DrNomis_44
28-02-2018, 08:55 PM
Since I've got a Digital Multimeter that can measure capacitance, I should try measuring the capacitance/m of the Response WB-1530 cable I buy from my local Jaycar Electronics store, would be interesting to see what result/s I get, I think I've got a 1m length spare somewhere.


For those of you who want to know, a capacitor is formed whenever we have two conductors that are close together, but separated by some kind of insulation material, in the case of shielded cabling used to make instrument leads, we have two conductors, the inner core and the outer braid shielding, and an insulator, the plastic covering of the inner cores.

Okay, I've just tried measuring the capacitance of 1m of Jaycar Electronics WB-1530 cable, with my Digital Multimeter set to the 20nF range, I got a reading of 0.39nF (390pF), next I disconnected the two probes from the cable and measured how much capacitance the meter probes were contributing to the result, it turned out to be 0.06nF (60pF), if I take 60pF away from 390pF, that gives us a total of 330pF/m (with both of the inner cores connected together).


Bit of trivia, the basic unit of capacitance is called the "Farad", it was named after Michael Faraday, a famous British scientist and physicist, now the Farad is a very large unit of capacitance, a bit too large for practical use in Electronics but there are 1 Farad capacitors available, the Farad can be broken down into smaller units of capacitance:


1 Farad = 1000 mili-Farads.

1 mili-Farad = 1000 micro-Farads.

1 micro-Farad = 1000 nano-Farads.

1 nano-Farad = 1000 pico-Farads.