This article is a kind of “audio do-it-yourselfer’s newbie FAQ”, with a focus on tools. If you’re thinking of getting started in audio DIY, this will help you assemble the tools you need to get started.
You might also check out my training videos. The first several present much the same information as below, so watching them will reinforce what you learn here.
First, I should point out that I can only advise about tools sourcing within North America. Some of my advice may not even be valid outside the US. Skip this section if you are from somewhere else.
With Radio Shack, you have to be kinda choosy about what you buy: some of their stuff is certifiable grade-A junk, and some is quite usable. Everything they sell can be bought elsewhere, and usually cheaper or better quality for the same price. Their stores don’t have a great selection of tools, and if you’re going to mail-order tools, there are better places to do that than at radioshack.com. The main advantage of Radio Shack is that you probably have one nearby.
Lately I’ve been getting tools from Mouser and Allied, mainly because I’m often needing other things from them anyway. I haven’t found bad tools within their catalogs; if they have it and you need it, it’s a good place to get tools.
If you need a broader selection than Allied and Mouser have, the best place for getting tools and supplies for electronics is Stanley Supply & Services. They don’t carry low-end tools, so their prices may look high, but if you compare on quality their prices are quite fair.
To start work as an audio do-it-yourselfer, the minimum set of tools is a soldering iron, solder, a stand for the iron, small screwdrivers, small cutters and pliers, and a wire stripper. You will also need a variable-speed drill and assorted drill bits for casework.
Most any pencil type iron will work. In addition to the standard electrically powered ones, there are also butane powered ones that heat a standard metal soldering tip; these work fine, too.
Butane-powered soldering irons are distinct from the small butane torches with open flames; these may be billed as “for soldering’, but only for heavy metal surfaces, not electronics. Also avoid soldering guns: these are too clumsy for use on modern small electronics, and they’ll likely overheat the board and components. Finally, avoid the new “cold heat” battery-powered irons; they’re a cute idea, but as discussed in the links below, the implementation leaves much to be desired.
The best places to get good pencil irons are specialty electronics supply shops, both in the real world and online. The pencil irons available at Radio Shack and home improvement stores are generally of poor quality. They tend to have broad tapers so they’re unsuited to delicate work, they become difficult to clean over time, and I’ve seen their tips shatter when cleaned too many times on a damp sponge even though this is standard practice. This isn’t to say that you can’t use one of these irons, just that it won’t last very long and it will be frustrating to use.
You can pay as little as about $9 for a decent pencil iron. Even with a good stand, you should be able to keep it under $20. Higher quality irons add fast-heating ceramic elements, burn-resistant cords, grounded wiring, antistatic construction, and various levels of temperature control. A high-quality iron will also be designed to be repaired, rather than replaced. There isn’t much that’s worthwhile between about $25 and nearly $100. You have to cross that gap before you start getting into the decent-quality temperature-controlled soldering stations. If you can’t afford to make the jump, my advice is to stick with regular pencil irons.
Standard pencil iron tips are either conical or chisel shaped. (Also called “needle” and “screwdriver” tips, respectively.) You can get them in various tapers and widths. I’m partial to chisel tips since they have more surface area for faster heating. Bigger is generally better, up to the point where the the tip is wider than the surfaces you’re trying to join. For instance, the pins on chips in DIP packages are about 0.05" wide, and the pads on the board are rarely bigger than 0.075" in diameter. If this is the smallest thing you solder, a chisel tip in this range would work well. My inclination would be to stay toward the lower end of that range, to be able to solder the occasional smaller part. The bigger the tip, the more likely you will create solder bridges between pins. Don’t neglect the possibility of having several tip sizes on hand, to tackle different jobs.
If the iron doesn’t have temperature control, the wattage and tip size determine how hot it gets. You want an iron that will melt the solder readily, but won’t burn your board or damage heat-sensitive components. For standard non-adjustable pencil irons, something in the 15W to 30W range will work best. The smaller the parts you will be using, the closer to the low end of that range you want to be. (The wattage of a temperature controlled soldering station will typically be much higher than 30W, but the temperature regulation makes this irrelevant.)
There are many types of solder. The three main variables are the alloy type, the thickness of the solder wire, and the type of flux it carries.
The cheapest type of solder for electronics is 60/40 solder — 60% tin, 40% lead. I don’t like it, and I can’t recommend it.
A nicer alloy is 63/37. This is a “eutectic” blend, which means it transitions straight from liquid to solid without a pasty state in between. With non-eutectic solders like 60/40, you have to be careful to keep the joint still while it goes through this pasty state or it may not form properly. If the solder joint doesn’t solidify properly, your project may not work at all, and even if it does, the joint may fail in the future.
If you want to get exotic, there are various blends with silver, varying from about 2-4%. Some of these have significantly higher melting points than standard solder and many are non-eutectic, so they may be harder to use. The advantages are that silver conducts better, joins to various metals better, and is better for surface-mount work. My favorite such blend is 62/36/2: it’s not horribly expensive, it has enough silver for SMT work, its melting point is reasonably low, it’s readily available, and yes, it’s eutectic.
There are also no-lead solders. Some are created to ease the environmental impact of lead in today’s throw-away electronics. But beware, there’s also plumber’s solder, which is lead-free for more direct health reasons, but which isn’t suitable for use in electronics. (More on plumber’s solder below.) I’ve only used one no-lead blend myself, a high-silver (4%) type which I use for joining materials that don’t accept regular solder readily. It has a pretty high melting point, though, so it’s not really suitable for general electronics work. The advent of RoHS has me thinking about trying some of the newer lead-free blends made for electronics, if only so I can report on it here, but I haven’t gotten around to it yet. You’re on your own for now if you live in a country where your only choices are lead-free.
You might be asking whether it’s environmentally responsible to continue using leaded solders. As a DIYer, I keep almost everything I build, throwing out only that which is completely hopeless. The rest I can fix, give away, sell, or keep in my personal little museum of past projects. Sure, some of this will end up in the landfill eventually, but DIY is such a tiny piece of the electronics world that it cannot be significant. It’s arguable whether solder even poses a real problem, so it’s doubly dubious for hobbyists to avoid use of leaded solder. The only risk lead poses for DIYers is that you may forget to wash your hands after finishing a project. We use leaded solders in electronics because they work. If you live in a country where leaded solder is not yet banned, I recommend you hoard a little for personal use. A pound or two will suffice for a lifetime of projects for most DIYers.
The choice of thickness is a personal preference, but it also depends on what you’re building.
For most electronics work, I prefer 25 or 32 mil wire. (About 0.6 to 0.8 mm.) Thin solder wire is easier to handle and it is easier to make lightweight joints with it. If you use too much solder on a joint, you risk solder bridges. Plus, you can’t really “maneuver” thick solder wire: you have to hold it by the spool and poke with the extended wire at the iron, instead of guiding the bare solder wire to the iron.
That said, I do keep a half-pound spool of 62 mil (1.6 mm) 63/37 solder around for use on large connectors: RCA cables, XLR jacks, IEC power connectors, tube sockets... Being able to dump the solder on in buckets makes the project go a little smoother.
You can find solder as thin as 15 mil (0.4 mm), which is really only useful for fine-pitch surface-mount work. The cost of solder per pound goes up as the thickness goes down, so I can’t see much reason for a DIYer to use such solder.
Flux is a gooey or liquid substance in the core of the solder wire that removes oxides from the surfaces to be joined and helps the solder to flow while it’s still liquid. (Burning flux is the source of the smoke and smell of soldering.) If the solder can’t bond to the metal surfaces or the solder doesn’t flow well, you get a bad joint. Molten solder actually doesn’t flow very well on its own; flux is absolutely essential.
There are three main categories of flux: rosin, water-soluble, and acid.
You can rule out acid flux immediately. It’s made for plumbing, where they need it to eat through a thick layer of copper oxide very quickly. It eats circuit boards pretty well, too. Don’t use it for electronics.
For general-purpose hobbyist work, I recommend rosin flux. There are several kinds. The main variables are the “activity” of the flux (how good it is at removing oxides), whether it’s clear or colored, whether it’s conductive, and how tough it is to remove from the board. The ideal for maximum ease of use is a mildly-active, clear flux that’s non-conductive so you can just leave it on the board. Myself, I clean my boards no matter what kind of flux I’m using, just as a matter of course, so I don’t pay too much attention to the type of rosin in the solder I use. If you want a recommendation, I can say I’ve been happy with Kester 44, but I have no particular loyalty to it.
Water-soluble fluxes are primarily for use in high-volume electronics assembly applications. Electronics assemblers go through so much solder (and thus so much flux) that the environmental problems involved with the solvents necessary for cleaning rosin fluxes poses a real problem. The downside of water-soluble fluxes is that they are acidic: not nearly as acidic as the flux in plumber’s solder, but enough to be a problem. This is fine in industrial work, where everything they make is cleaned, tested, and installed, likely never to be touched again. In DIY, you may remember to clean the board after it’s complete, and you may even do a good job of it, but you might forget to re-clean it if you decide to go and start tweaking the circuit again. This is DIY...we tweak. I’d rather use a flux I don’t absolutely have to clean, so if I forget or I don’t do an excellent job, it won’t matter.
Unless you’re perfect, you will need some kind of desoldering tool to desolder components and remove excess solder.
Some people like to make a big debates about desoldering pumps (a.k.a. solder suckers) versus desoldering braid. I find both useful, for different reasons. I use braid for almost everything except for clearing solder out of a thru-hole in a circuit board after the component is out. Because you can’t sanely use a desoldering pump if you don’t have easy access to both sides of the board, sometimes I’ve had to use braid for clearing a hole, too. Braid is also useful for cleaning up excess solder. If it sounds like I’m in favor of braid, I am, but within their limits, desoldering pumps are the best way to clear solder out of thru-holes.
A useful hybrid is a desoldering iron (I use RS 64-2060), which heats the joint and then lets you suck the solder up into the iron’s hollow tip without removing the iron. It will cost you $10, or about the cost of a basic solder sucker and a 5' spool of braid. Because one hot object on my crowded bench is enough for me, I only use the desoldering iron when braid and the solder sucker both fail, or I’m doing mass desoldering (read: scavenging dead electronics for parts).
When your project is completed, you should clean the solder flux off of your board. My method of choice is to use a stiff-bristled toothbrush and some form of pure alcohol. I load the toothbrush up with lots of alcohol, use this to wet the board surface thoroughly, and then scrub it vigorously for several seconds. Then I blow the fluxy alchohol off the board with a can of compressed air. With small boards, one cleaning is sufficient, but with larger boards you have to repeat this process a few times to get all the flux off.
The only truly pure alcohol available is synthesized for chemical lab use, and is therefore quite expensive. Everything else is some form of “natural” alcohol and therefore has some amount of water and impurities in it. The higher the percentage of alcohol, the faster it will evaporate and the less junk it will leave behind on the board. It really is worth your while to seek out alcohol of 99% purity or higher. I’ve tried 90% isopropyl, which theoretically should be pretty good stuff, but it still left behind visible residue.
You can get high-purity alcohol from Radio Shack and Stanley Supply & Services. Radio Shack has small bottles of alcohol for tape head cleaning (44-1113D) which will cost you about $1 per ounce. At Stanley Supply & Services you can get a gallon of 99% isopropyl for about 20 cents per ounce including shipping, but then you have to figure out what you’re going to do with a gallon of alcohol. :)
An alternative to alcohol are the various defluxing solvents. They’re usually no faster than the alcohol and toothbrush method, but they’re guaranteed not to leave behind a residue and they usually come in spray cans with brush attachments so they’re easy to use. I find occasional use for them because the liquid doesn’t evaporate quite so fast, so it can be useful when I need a little more time to work than pure isopropyl allows for, such as with large boards. Isopropyl does the trick for me most of the time, though.
A basic meter measures voltage (AC and DC) and resistance (ohms). All but the cheapest meters also have current (amps) metering. When you want to talk about just one function of a meter, you refer to voltmeters, ohmmeters and ammeters.
There are two classes of meters: analog and digital. Analog meters are traditionally called VOMs: volt/ohm/milliammeters. Digital meters are also called DMMs: digital multimeters. Both are useful for DIY audio.
DMMs are the most popular, because they’re generally easier to use than analog meters, have more features, and are more accurate.
Better DMMs can “auto-range,” meaning that they will automatically find the right measurement range for you, instead of making you pick it from 3-5 ranges on the dial. This is analogous to the difference between automatic and standard car transmissions: an automatic tries to guess the right gear for you, whereas a standard transmission requires you to pick the gear you want when you want it. Autoranging is convenient, but like a car with an automatic transmission, there’s a downside: it raises the cost of the meter, and the meter takes some time to “hunt” for the range. Better autoranging meters will let you force it to use a specific range when you need it, so that it delivers the measurement quicker.
Another advantage to DMMs is that they handle negative measurements naturally. When measuring voltage or current, an analog meter requires you to hook the leads up the right way, or the needle will try to go backwards, which on most meters means the needle just sits at the 0 position, indicating nothing. A DMM will simply display a negative number.
The main advantage of an analog meter is that they react quicker than DMMs: your typical DMM only updates its display once or twice a second, and sometimes an autoranging DMM will “hunt” for a few seconds to find the correct range. Analog meters react almost instantaneously. This can make them more useful when looking at a voltage that’s varying, as you can see the trend visually. With a basic DMM, discerning the trend of a changing voltage requires that you do a lot of quick arithmetic in your head. More advanced DMMs have what they call an analog bar graph which helps a bit in this regard, but it’s still not as intuitive as a true analog meter.
It is not essential that you get a meter, but it is highly recommended, for many reasons:
The primary reason to have a meter is that without one, troubleshooting is reduced to sheer guesswork. No fun at all.
Second, it’s quicker to use a meter to measure an unknown resistor, capacitor or inductor than decipher some of the more arcane value codes in use. Also, some parts are mislabeled or unlabeled.
Third, an ohmmeter is useful in figuring out cable and connector pinouts. The alternative is to find the connector’s datasheet, which may not exist or may be difficult to read.
Finally, some people like to match components in one stereo channel to the corresponding component in the other. See this article for more details. Executive summary: it’s expensive to do this right, which is why this is the last reason on this list.
For advice on how to choose a meter, see my article How to Buy a Multimeter. (Much of its contents used to be here, but it got too long, so it now stands alone.)
Most projects will require hookup wire. The gauge you use depends on the project, but I find 24 to 22 gauge to be the best balance between size and workability for general use. 22 gauge is just barely small enough to fit through protoboard holes when tinned. I generally go up to 18 gauge for power supply work, though. (Higher numbers mean smaller wire; larger wire can carry more current without getting hot.)
Some people like stranded wire, and some like solid. There may be a sonic difference, but to me the main difference is that solid wire is stiffer and thus harder to work with, so I prefer stranded wire.
There’s also the matter of the insulation type. You can get basic PVC-coated hookup wire almost anywhere, but I go a little out of my way and spend a little more to get irradiated PVC. Irradiated PVC is thinner for a given level of short circuit protection, and it doesn’t shrink when heated, as regular PVC does. This property means that regular PVC insulation creeps up away from a solder joint while you are working on it, which is annoying and can cause problems. If you want to get a little fancier, you can use Teflon-coated wire, which also doesn’t shrink when heated, plus it’s a better insulator and moisture barrier than irradiated PVC. As a consequence, it costs more.
If you’re not looking to get exotic, the wire itself should be copper. Copper wire is often plated with another metal to prevent oxidation. With PVC insulated wire, the plating is solder, usually called “tinned copper”, even though it isn’t really pure tin. They can’t use solder with Teflon-insulated stranded copper wire, though, because the melting point of Teflon is higher than the melting point of solder, so the wire strands would fuse together if they did it that way. Instead, they usually use silver, because it’s the best balance between high conductivity and low oxidation. You also sometimes see nickel plating, which trades conductivity for even lower oxidation, a bad tradeoff for typical audio use, since silver oxides generally aren’t a problem. If you want to get exotic, you can get pure silver wire instead, but it can cost $5/ft!
There are many other tools that come in handy. I find frequent use for picks/probes (Radio Shack part 64-2227 or 64-1941), “helping hands” (RS 64-2063), a hot glue gun, hook adapters for meter probes (RS 270-0334), alligator jumpers (RS-278-1156), an X-acto knife, and a Dremel tool. Another recent acquisition I’m really happy with is a solder spool holder; they work like a Scotch tape dispenser for common 1 lb. spools of solder. ( More >>)
I won’t try to recommend casework type tools. For that, you should read Apheared’s Guide to Project Casing Tools.
If you don’t yet know how to solder, watch Watch Tangent Tutorial #2.
Always remember: good tools are an investment, not an expense. If you buy cheap tools, you get to replace them next year. If you buy quality tools, you get to hand them down still in working order to your grandchildren.
Looking for a great first-timers’ DIY project? Continue to the companion article...
Removed tool kit tables. They were continually out-of-date, inobjective, and kind of beside the point of the article anyway, which is to teach you how to pick your own tools.
Rewrote much of the bits on solder and flux types. Also, a lot of general clean-up and polishing.
Extracted most of the multimeter material out into its own article.
Updated Radio Shack part numbers and prices.
Rewrote most of the sections that I didn’t change in the edit 3 weeks ago, and changed some of those again, too.
Made the section links easier to use.
Reworked the sections on meters, and removed the “pre-assembled tool kits” section.
Almost completely redid the tool kits: checked part numbers, removed the Radio Shack mail order part numbers, and added Allied part numbers. Several clarifications, as well.
Updated the article to reflect my current opinions and the add information and tips I’ve discovered since the last update.
Major update: added the tools tables, and added a lot more info on how to choose soldering irons and solders. A more balanced presentation overall, more accessible to the person who doesn’t want to spend very much on tools. (Poor misguided souls...)
This article is copyright © 2001-2013 by Warren Young, all rights reserved.
|Updated Mon Sep 22 2008 12:14 MDT||Go back to Audiologica||Go to my home page|