DIY Music Equipment Repair

Unfortunately, there comes a time when everything breaks, and the same is definitely true of music gear, whether it’s speakers, valve amplifiers, or your electric guitar or bass. In the worst case, you’ll need to get it fixed by a professional, but there are some smaller, more simple repairs that you can actually carry out yourself. With a voltmeter, a soldering iron and a little solder on your side, you can get more done than you might think.

The Basic Musician’s Toolkit
Cable Tester
Voltmeter
Regular Maintenance is the Best Fix
Give Your Valve Amp a Checkup
Replacing Valves
Good Prep is Half the Work
Guitars & Basses
The Art of Soldering
Make a New Connection
Prepping
Clean Up
Finishing
See also…

The Basic Musician’s Toolkit

Since most technical issues are just caused by knackered cables, you can start by always having some spare cables handy so you always have a quick solve. Having a few adapters and cables like an XLR to jack lead is never a bad idea either, but the first thing to kit yourself out with is a simple little box that you can keep all your life-saving cables and tools in. Then you can start filling it:

Various adapter cables and adapters.
A voltmeter and cable tester (see below).
A set of screwdrivers and some wire cutters.
A soldering iron, some solder and accessories.
A pocket torch.
Some 9 Volt batteries (for gear like effect pedals and wireless microphones).
Deodorant, some plasters, and paracetamol (obviously).
That’s all the tools you need! And if you have a problem that does need more tools, then it probably needs to be fixed by a pro.

DIY Music Equipment Repair
Left: a voltmeter, right: a cable tester

Cable Tester

As we already know, cables are the number one cause of on-stage issues. Cables can suddenly stop working because of a breakage or because of loose soldering in the plug, and neither of these problems can be seen without opening the cable up. Using a cable tester, you can quickly check if a cable is still transferring signal or not.

Voltmeter

Sometimes, something could be up with the mains power supply. Using a voltmeter, you can quickly and easily check if you have the right voltage. Of course, if there is something up with the mains power supply then that’s something you just can’t fix yourself, but at least you now know where the problem lies, and you actually have proof. Then it’s up to the venue to solve it. Electrical problems can often occur when playing shows on location in a tent and at festivals since the power is provided by a generator. Sometimes the beer fridge and the deep-fat-fryer are hooked up to the same generator, which will lead to some beautiful hum and noise on stage. It could be worse though. When a cooling system is activated, the power surges, and sucks all the power from any equipment connected to the same system – music equipment included. This can be a nightmare, since it can spontaneously reset your gear, so you lose all of your settings. The best method to use when it comes to these kinds of setups is to provide a separate group for any music equipment, or when using generators, just use a separate generator for the stage and another one for the bar and burger van.

Regular Maintenance is the Best Fix

Many possible problems can be avoided altogether before they even have a chance to happen. So, for example, why not spend a rainy Sunday afternoon sticking all of your cables through a cable tester, unscrew all of your plugs and check that all of the wiring and soldering looks healthy. Keeping your gear clean is also important. Dust is the sworn enemy of any electrical equipment and likes to creep in through any faders and pots, so for a start, keep everything dust free and check and clean out the dust filters of your PA system.

Another arch enemy of electronics is moisture. Always store your gear in a dry and preferably warm room, and when you bring cold equipment into a warm venue, give it a chance to acclimatise – people who wear glasses will immediately know what I mean. When you come inside on a cold day, your glasses will immediately fog up with condensation. The same thing happens to cold equipment. So, give any possible condensation time to evaporate before you even think about switching your gear on.

Give Your Valve Amp a Checkup

In theory, the valves fitted inside a valve amplifier have a 20,000 hour lifespan. If a valve stops working, then it’s likely to be because the filament is broken which is actually easy to see. Normally, the valve will give off a soft red glow when it’s active, so if it doesn’t, then you know that the filament is broken and that the valve needs replacing.

Preamp valves can also become microphonic: where they literally start operating like a microphone and produce noises that you just didn’t ask for. This occurs when the mica plate on which the electromagnetic components inside the valve are suspended has come loose. This happens because of repeated vibrations caused by being carted around in the back of a car or van, or if we’re talking about a combo amplifier, then the vibrations caused by the built-in speaker. You can test to see if a valve has become microphonic by carefully tapping the active bulb with a pencil (or something else that’s not conductive). If you can hear the tapping through the speaker, then you know that the valve has become microphonic and needs to be replaced.

Replacing Valves

The story goes that you should never touch a valve with bare fingers, but that’s actually not true. It’s definitely true of hot lightbulbs, but when it comes to radio valves like ones you’ll find in a guitar amplifier, while they can be described as running ‘hot’, they don’t actually get all that hot – just a little warm. You can easily replace preamp valves yourself, but life gets a little bit more complicated when it comes to replacing power amp valves. Why? Because when replacing power amp valves, something called the quiescent current also needs to be taken into account. Power amp valves always come in pairs and each member of the pair needs to produce the same current as its partner. The problem with valves is that they tend to come with their own character – even two identical valves of the same model type can have entirely different characteristics, which is compensated for by adjusting the quiescent current. The preamp section doesn’t have this problem since the valves don’t need to be paired. So, if you really need to replace your power amp valves, then you’ll need to remove and replace both of them with a matched pair that have been teamed up because they share the same characteristics.

Good Prep is Half the Work

Many problems can also be prevented by using good protection. A strong flight case or cabinet is always the best option. Note that valve-driven amplifiers are much more sensitive than transistor amplifiers, since heavy shocks and vibrations can break the valves. If your valve amp is fitted with wheels, then avoid rolling it over cobbles or uneven pathways. Pack your valve amp up in a flight case or set it on a base fitted with larger rubber wheels to get it safely from the van and into the venue.

DIY Music Equipment Repair

Guitars & Basses

Noise and interference can mess with the sound of an electric guitar or bass due to a shoddy jack output or crackling pots. This is stuff you can easily repair yourself (at home mind you, not backstage just before a gig). If you have a noisy jack output, a little contact spray will definitely help and if it doesn’t fix the problem, then the input is actually really easy to replace. If you have crackling pots, then just replace them. With most guitars and basses, the jack output and pots are easily accessed by unscrewing a backplate. With Fender guitars, the pickguard will need to be unscrewed. You can get fresh pots and jack outputs at shops that sell electrical parts, and at some music stores. If you want to know more about repairing and looking after your electric guitar or bass, then see this purpose-written blog.

Elektronica van een elektrische gitaar repareren? Zo doe je het zelf!

The Art of Soldering

Soldering is one of those skills that you just get better at the more you do it. But with the following little tips, your first time should go smoothly. A little soldering job that you’re likely to do regularly is fixing a broken jack plug, which is repaired in the following way. Click on the images to enlarge them.

Make a New Connection

Most of the time, if a jack plug isn’t working, then one of the two internal connections has broken. Rather than trying to fix the breakage, it’s far better to make a fresh connection, so start by removing both of the wires that you’ll find soldered to the jack plug and starting again. This is done by using your trusty soldering iron to remove all of the solder and taking off the plug. Once that’s done, trim the raggedy end of your cable off using a knife (see image 1, and see the result in image 2). Then, twist the copper wires until they’re bound (image 3). Some cables have an extra conductive mantle inside (‘dual shielded’), but not always.

Prepping

Now, you need to bind those copper wires using a little solder. Hold your soldering iron against the solder until it melts and can be applied to the copper wires – it melts fast so be careful (image 5). Now, strip the core (image 6) and apply a little solder to the exposed wires to bind those as well. Once done, cut both the core and copper braid to the right length (you can find the right length by checking it against the jack plug, or by opening up a working plug and seeing how long they are).

Clean Up

Before soldering the wires to the jack plug, you’ll need to clean any old solder and dirt off the plug. You can do this with the help of your soldering iron and some desoldering lint – otherwise known as solder sucker since it literally sucks up melted solder (see image 8). The cleaning step is absolutely essential so that the new solder will stick and you’re assured of a clean and secure connection. Note that solder doesn’t act like glue or the stuff you use to weld with. Solder is an alloy made of lead and tin which actually penetrates the copper during the soldering process and forms a whole. These days, industrial soldering is prohibited because lead can be harmful in large quantities, so industrial soldering uses silver solder instead. Since you’re not likely to be exposed to so much lead, soldering at home using standard lead and tin alloy solder won’t cause you any harm. However, this is another reason why the old solder will need to be completely removed, since it’s very likely to be silver solder, which your old-fashioned solder will have trouble binding with.

Finishing

The last step is to solder your jack plug back onto your newly stripped and prepared cable. The outer copper wires are soldered to the outer tip – which is the positive tip, and the central core of your cable is soldered to the inner, negative tip of the jack plug. It sounds straightforward, but it’s essential if you want your jack lead to actually work.

Before you do anything else, apply a little solder to both the outer and inner tip of the jack plug, just like you did with the loose wires. This is so that the solder on the wires will meld together with the solder on the tip. When soldering, always heat the biggest bit first, and once it’s up to temperature, melt the smaller bit into it. So, when soldering wires onto a jack plug, it’s best to heat the solder on the tip and then the solder on your wire before bonding them. Why do it in this order? Simply because a bigger bit of solder will take longer to come up to temperature than a small bit. If you heat the small bit first, then it will have completely cooled by the time you’ve heated the bigger bit. Makes sense, right?