Decibel Dungeon


Introduction


Starting any new hobby can seem daunting if you don't know anything about it beforehand. Where do you get the skills and knowledge from? Do you have the necessary resources to be able to do want you want to do?
These concerns are especially relevant when the hobby concerned is of a technical nature like hi-fi. But don't be put off; I didn't have any training or experience in electronics and yet I have managed to put together a fairly decent hi-fi system after only a few years of 'doing-it-myself'. I hope to show you that even if you have done nothing like this before, you can do the same.
Obviously, to put down all the information I have accumulated over the last few years is a major undertaking and I have to start somewhere. I intend to elaborate on some of the topics covered on these pages as time allows so bookmark this page and visit it again from time to time.
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Is it Safe?

Safety WarningThere are some aspects of DIY hi-fi that do not require you to get involved with electricity but if you start opening up items like amplifiers and CD players, you will be encountering parts of your equipment which carry high voltages that could cause death, personal injury or damage to property if you are not extremely careful. The mains voltage in the UK is around 230 volts. In some other parts of the world it is 110 volts but this is still enough to kill!
This may seem like a bad way to encourage you to take up this hobby but there is no getting away from the fact that working with electricity is dangerous. But so is crossing a busy road and if you take suitable precautions neither activity need result in a disaster. There are aspects of hi-fi which don't involve dealing with potentially dangerous electrical voltages and maybe it's best for complete novices to start their hi-fi DIY career working with items such as loudspeakers, equipment supports and hi-fi accessories like interconnects.
Many do start with loudspeakers, either modifying models they own or building new 'speakers from a kit of parts or from scratch. Building a pair of 'speakers from a kit was how I 'put my toe in the water' with this hobby and it provided me with the confidence to go on to more adventurous projects.
Once you start either building or modifying mains-operated items like amplifiers you should remember that parts of the equipment contain higher (potentially lethal) voltages while other parts of the equipment involve relatively lower and safer voltages. Often, suggested upgrades to this type of equipment involve you working on the parts with the lower voltages and provided that the item is NOT connected to the mains supply while you are working on it, there is very little danger of getting an electrical shock.
As regards the part of the equipment which involves the higher voltages, you should not even attempt to work on these until you are confident that you know what you are doing. The same goes for any modifications to the mains electricity supply although to put this into context, many of you will have fitted a plug to a piece of electrical equipment with due care and attention and (hopefully) no resulting calamity.
Many of the better books and internet sites which give advice on hi-fi contain their own warnings about working with electricity. (An example at ESP) Take note of them, they are there for your safety. Ironically, it is when you become more confident in your hi-fi skills that you can become a little complacent about the issue of safety. Constantly remind yourself that you don't want to destroy the (probably expensive) equipment you are working on and more importantly, you don't want to cause yourself injury, or worse.
Please note that some hi-fi equipment uses valves instead of transistors to produce gain (increasing the signal strength). Valves operate at very high voltages which are typically twice as high as the 230 volts of the British mains supply. For this reason I do not recommend novices to build, modify or service valve equipment.
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What does it involve?

So what exactly is involved with hi-fi DIY? Well, there are literally hundreds of things that you can do to a hi-fi to make it sound better (and quite a few other factors that you can alter like your listening room).
Maybe we should start by asking what exactly do we mean by a hi-fi system. The diagram below represents a typical hi-fi system and lists most (but not all) of the possible permutations. Media eg, LP, CD, Minidisc, Cassette Tape, Tuner.
Source component eg Turntable, Cd player, Tuner, Cassette deck, Minidisc player.
Amplification eg Integrated, separate pre+power, mono bloc or stereo amplifier.
Transducer, eg loudspeaker, headphones.
Cables, eg Interconnects, loudspeaker cables.
Support, eg equipment racks, loudspeaker stands.

Hi-fi chain

Think of your hi-fi system in terms of a chain, starting with whatever media you are using eg CD, LP, Minidisc. This is where the music signal is stored. To retrieve the signal you need a source component such as a CD player or turntable. Often these source components are known as the 'front end' of the system. The source component retrieves the music signal which then needs to be amplified in order that it is powerful enough to drive the loudspeaker.
The next stage is, amplification. This operation is often (but not always) carried out in two sections known as the 'preamplifier' and the 'power amplifier'. The 'pre' and 'power' stages may be combined in one unit or have their own separate casings and power supplies. In a stereo system (nearly all of them are), there are two 'channels' of signal to be amplified hence we get 'stereo' amplifiers which can amplify both channels, and 'mono bloc' amplifiers which amplify only one channel. There are various reasons why amplifying each channel in separate amplifiers can give better sound quality although this is a more expensive solution as some costly items like transformers and casings are duplicated.
The preamplifier section also has controls for selecting the source (you usually have more than one) and controlling the volume. Sometimes there are facilities for altering the tone (amount of treble and bass) as well, although such controls are usually frowned upon by audiophiles who consider that the extra circuitry further corrupts the original signal.
Once amplified to a suitable level, the signal is sent to a transducer. In the case of hi-fi, a transducer is something which changes an electrical signal into something we can hear, ie sound, for example a loudspeaker or headphones. (A transducer is also used to change sound into an electrical signal as in the case of a microphone). Hopefully, sound comes out of the loudspeaker and, if we're lucky, it bears a fairly close resemblance to the original recording! The aim should be to get that sound as close (or true - fidelity means truth) to the original sound source as possible.
In order to get the signal from one component to the next one in the chain we use cables which carry the electrical signal. The cables used between the source component and the amplifier are known as 'interconnects' while those running between amplifier(s) and loudspeakers are called 'speaker cables'. The main difference between the two is that loudspeaker cables carry higher voltages (having been amplified by the power amplifier).
The final category in the 'system' is the equipment support, whether it be a piece of furniture or something made specifically for hi-fi components. The usual two types of support are the equipment rack for the source and amplification components, and 'speaker stands' which support the loudspeakers.
All these items in a hi-fi system, no matter which of the above categories they fall in to, can usually be modified to produce different results, hopefully better, but not necessarily so! Which you will give priority to depends on several factors:
  • How much it will cost and what amount of improvement you will get for the money. The law of diminishing returns is often a factor to be considered.
  • Your skills. If you have no electronic skills but are reasonably proficient at something like carpentry, you will probably make building a better pair of loudspeakers a priority over upgrading the power supply of your amplifier.
  • Information available. Often you will try something out after hearing about it from others. And like any other activity, hi-fi goes through fads and fashions and you often find yourself caught up in them.
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Getting the know how


This part of the site is aimed at the complete beginner and I make no apologies if I am 'teaching you how to suck eggs'. DIY hi-fi is a fantastic hobby and I feel that more people could (and would) enjoy it if only they realised that it isn't some sort of mysterious 'black art' and they knew where, and how to make a start.
I've already said that you could take up DIY hi-fi and still avoid working with potentially harmful electricity but in reality if you wish to understand what you are doing with the important areas of hi-fi, you will need to have a basic understanding of electronic components and theory. Don't be put off though, I'm not talking degree level stuff here. First an understanding of basic electronic components such as resistors, capacitors and transistors can be got from any of the thousands of books on the subject (many of which are written for schools and are easy to understand). The same books go on to describe enough basic theory to help you understand how you can upgrade your equipment by replacing some of the components.
Easier still, is to try some of the following links to basic electronics education:
If you are really keen, or feel that you need some guidance, why not try a suitable course at the local technical college. Many colleges run evening classes where you can not only learn the theory but be shown how to operate the relevant tools and equipment associated with electronics. Some colleges also allow to you to develop your own projects using college facilities.
Once you get started and decide exactly what it is you want to do, you can then set about finding the information which will enable you to carry out that job. As regards modifying (upgrading) existing hi-fi equipment, you will almost certainly need to get a circuit diagram/repair manual for the piece of equipment in question. Depending on the origin and age of the equipment you may be able to contact the original manufacturer and get a circuit diagram, and possibly some help and advice at the same time.
One good (independent) source of manuals for hi-fi equipment is:

Willow Vale Electronics Limited
Connect Business Park
Bordesley Green Road
Birmingham
B9 4UA
England
Tel: 0121-766-5514
E-mail Willow Vale

or try HERE for a Dutch source of manuals.
Many of the suppliers of parts used in upgrades can also offer valuable advice. Please don't take advantage of these people though, remember that they have a living to make and if you pester them you'll only make them reluctant to help others. I have included links to some component suppliers in the section on modifying equipment.
Of course, you can also look on the internet for help and advice, there's so much of it out there that the only problem is finding the bit that you want. Search engines are a great help here but if you have already found this site, I presume that you know how to use that facility. Remember, it helps to be selective when using a search engine; eg try '+amplifier +modifications' rather than just 'amplifier' on its own.
You could do worse than start off visiting some of the many hi-fi news/chat groups that exist. Here are a few suggestions:
  • uk.rec.audio
  • rec.audio.pro
  • rec.audio.tech
  • rec.audio.tubes
  • rec.audio.high-end
  • rec.audio.marketplace
For further recommendations go to the Links section on this page. While there, you will also see links to some of the other hi-fi sites which I have found most useful.
Patience is a virtue in this game and anyway, if you can get everything thing you want too quickly, you will have exhausted your hobby and be looking for something else to do! I didn't do too badly for information before I had internet access, but now I wonder how I ever managed without it.
Hi-fi magazines are another good source of information on DIY hi-fi. You will find surprisingly few books written on the subject but it may be worth a visit to your local library to see what you can find in the 'electronics' section. Books on loudspeakers are more common and I have listed some of the more useful examples in the section on loudspeakers.
In the UK, there have been several specialist publications for hi-fi DIYers and it's worth looking out for back copies. Some of the UK examples include:

  • 'Audio Conversions' - 16 issues published in the early 1990's.
  • 'Common Ground' - 3 issues published late 1990's then mysteriously disappeared!
  • 'Hi-Fi World DIY supplement' - usually published bi-monthly from mid 1990's and still going.

Update 2007
The hi-fi forums are undoubtedly one of the best sources to get help and information, although some are much better than others. And a word of caution here too! In the land of the blind, the one-eyed man is king. If you are starting out, any idiot offering advice can sound like an expert when often they are not. I'm sorry to say that on most forums you will find at least a couple of guys who think along the lines. "If I post enough times, that makes the expert on this forum." Well, of course, it doesn't work like that, but somehow, by posting enough, they become perceived as the resident expert! So be careful, if you are not sure of something, try and double-check it on another forum. Watch out for anybody recommending that you buy something expensive. Also be wary of the guys who promise hi-fi nirvana if you use a particular capacitor, change your mains cables, or stuff your CD player full of damping material. Again, look out for the extravagant claims like "I changed to this capacitor and it dramatically improved the sound of my whole system!". Most often any change or tweak makes a subtle difference but some guys just can't help exaggerating! Having said all this, I repeat, there is probably no better source of help and information than the hi-fi forums so here is a list of some of the ones that I use: There are many more hi-fi forums, some specialising in a topic such as loudspeakers, or even a particular type of loudspeaker. As ever, Google is your best friend if you need to find information on a particular subject.
I must say here that, almost without exception, I have found everybody involved with DIY hi-fi to be super-friendly and helpful. Once you have built up a small group of contacts you will find that there is always someone to help you if you get stuck, even if it's only to point you in the right direction. I'm not going to list the people who have helped me (as much as I would like to publicly thank them) for obvious reasons. Finding a few thousand emails in their 'inboxes' requesting help doesn't seem like a very good reward for their kindness!
For information on where to buy electronic components (in the UK) please click HERE.
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Getting the skills


Probably the most difficult (practical) skill to learn in DIY hi-fi is that of soldering. Soldering is not very difficult to learn but it should be practised so that you are good at it before you start working on anything important like your (or anybody else's) equipment. Several short books have been written on the subject so check out your local library, or

look here for some soldering tips. Another very good reference on soldering can be found here .

Perhaps you know someone who uses a soldering iron and would be prepared to give you a few lessons to get you started.

TIP - get hold of a piece of defunct electronic equipment, anything will do, an amplifier, CD player, tape deck. Make sure that the item you have isn't worth saving and then set to work opening up the case (making sure it is disconnected from the electricity supply first!). Inside you will be unlucky if you don't find a PCB (parts circuit board) containing a selection of electronic components like resistors and capacitors. Do what is necessary to get this PCB out of the case and, hey presto, you have something to practise your soldering (and desoldering) skills with that doesn't matter if you make a mistake. Spend a few hours practising and you should soon become quite competent. You will probably also have acquired enough confidence to work on some of your own equipment. This is particularly useful for learning how to cope with SMD components too!

SMD stands for 'Surface Mount Device' and refers to components that do not have the usual leadouts that go through holes in the PCB. Instead these components are soldered to the tracks on the surface of the PCB. SMD components are typically much smaller than standard components and make for a much more compact circuit. Usually SMD components are machine soldered to the board at the time of manufacture but it is possible to hand solder them too.
From this stage, many hi-fi DIYers move on to making up their own interconnect and 'speaker cables using their new found skill to neatly solder the appropriate plugs on each end of their chosen cable.
Apart from learning how to solder, there are few others skills to learn for the actual construction side of hi-fi. Of course, if you intend to build speaker cabinets and equipment casings then you will need to have the relevant skills to work with the materials that you choose to use.
There is one more important skill that is required though. That of being able to listen. Yes, I know you are probably not deaf but it's one thing to hear and another to actually listen. With hi-fi we need to learn to undo the automated part of our hearing system, the bit which shuts out things like surface noise on records after a short time. We have to really listen to what's coming out of the loudspeakers, to such a degree that we may not at the time to be able to fully enjoy the music as we do normally.
Nobody is suggesting that you do this all the time, remember the goal is to make our listening more enjoyable, but at times, it is necessary to work out just how a change we have made to our hi-fi system has altered the sounds coming out of it (if at all). In other words, we need to listen more objectively than subjectively. Of course, we all have different hearing to some degree and this will often lead to differences of opinion in hi-fi circles. Once you learn to really listen to your hi-fi you will find your listening skills develop over a period of time to a level where you will be quite surprised at what you didn't hear in the past!

TIP - Try to get out and listen to 'live' music on a regular basis. This will give you a clearer idea of how the music coming out of your hi-fi should sound.

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Getting the tools and equipment


It's very difficult to think of a hobby that doesn't require the use of some tools. Of course, how much you need often depends on how far you want to take your hobby and this is particularly true with DIY hi-fi. For instance, if you take up loudspeaker building then you will need the appropriate carpentry tools. As regards the electronics side, a minimum toolkit would probably include:
  • A multimeter
  • Soldering equipment, an iron and solder sucker
    When I asked members of the London Live Hi-fi Circle which iron they recommended, the result was almost unanimous. Nearly all suggested a 24 volt/45 watt iron made by Weller. Apparently, it is just about the standard iron used by British industry. The more experienced members felt that the extra cost of a good soldering iron was worthwhile.
    Click HERE for full details of a DIY power supply for the Weller iron.
  • A set of small screwdrivers with different blades
  • Needle nosed pliers
  • Side cutters
  • Wire strippers
  • A small pair of tweezers
  • A set of small spanners
  • A set of small size allen keys
  • A miniature electric (hobby) drill and bits

Hi-fi electronics toolkit
Most of your hi-fi toolkit should fit in one box

The above will enable you to do many of the jobs involved in modifying hi-fi equipment. Of course, if you get more ambitious and want to build your own equipment, you will probably require other (woodworking/metalwork) tools to make casings etc. You may even get so involved with hi-fi that you go on to purchase more expensive equipment like oscilloscopes, signal generators and computerised sound measurement systems but you can also achieve a great deal without them. OSCILLOSCOPE - an instrument for measuring items such as electrical currents or sound waves and graphically displaying them on a screen.
SIGNAL GENERATOR - device for generating sound signals of different frequencies and wave forms. Used to test hi-fi equipment.
In addition to the tools, it is a good idea to have 'in stock' items like solder, wire, electrical tape, small nuts and bolts, and isopropanol alcohol (for cleaning), none of which involve great expense.
One question often asked is 'what is the best solder to use'. While this is often a personal choice, a discussion on this subject at the London Live Hi-fi Circle produced the following summary:
There was one reply saying they did not like the 5.5% silver Maplin solder.

"There was one reply for lead free solder and another against the high temperatures required to melt it.

Also liked was the Audio Synthesis 200-010 Silver Solder 10m spool, 8.00 and Wonder Solder.

The most liked solder by far was Multicore LMP (low melting point) with 2% silver."


NEWFor those of you who like to design your own PCB's but don't want to spend a lot on a dedicated program, there is now a good (and inexpensive) alternative in the form of some software which works with Coraldraw to allow you to design PCB layouts. You can read more about this useful tool at The Merlin PCB designer site. You can try Merlin as shareware but with a price of only 12 euros, it's worth trying the full version.
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Is it worth it?


The answer has to be a resounding YES! I divide hobbies into two categories. Pastimes like stamp collecting fall into the first, where the hobby is an end in itself. You collect the stamps, sort them and put them in an album. You can look at them from time to time but you don't actually use them for anything. Hi-fi DIY, like household DIY, car maintenance and wine-making results in something which you can enjoy after the initial process of creating it.
I love listening to music, and did so long before I had anything to do with the hi-fi system that I was listening to, other than buying it. But now my pleasure is increased, enjoying not just the music, but the quality with which it is reproduced and a great deal of satisfaction in knowing that I have had something to do with improving that quality. Sure, there are some low points along the way, when something just wont work properly (or at all) but those times only make it all the more exhilarating when you do produce something which increases the sound quality of your hi-fi.
Personally, I prefer a hobby that will keep me occupied indefinitely and hi-fi certainly does that. Current technology can not produce a hi-fi that will sound perfectly real so there is no danger of finding that you have built a system that you no longer want to improve.
One aspect of hi-fi DIY that is appealing is the opportunity to own a better sounding system for less money. Although component costs are likely to be higher for the hobbyist than a hi-fi manufacturer (they order thousands where we would order one or two), our (spare) time costs nothing. But be warned, it is easy to get carried away and spend a lot of money on experimental projects which don't fulfill their promise. If an audiophile shows an you amplifier he has built and it sounds great, there is a good chance he built a number of prototypes along the way. My cupboard is already quite full with 'previous versions' although I don't begrudge the time and money spent if it has eventually led to a successful project. Thankfully, you can usually recycle many parts into another project and the experience gained along the way is priceless.
One big advantage that the home constructor has over a commercial manufacturer is not having an accountant looking over his shoulder while he is designing a piece of hi-fi and choosing the components to make it with. We also have no overheads and no dealer margin to worry about so providing we don't get carried away with too many prototypes we should always be able to produce something which costs less than the equivalent sounding item bought commercially.
Another point to consider is that there is no such thing as the perfect sound for everybody. That's why there is so much argument over hi-fi equipment. What pleases one set of ears may be irritating to another. When you have a say in the design of your hi-fi, even if it is just on a few parts, you can tune the system to get the sound that you feel is correct rather than the sound that the original designer preferred. If you choose to make your own casework and loudspeaker cabinets, you will also be able to choose exactly how your hi-fi looks (particularly important if you are trying to justify this hobby to your spouse).
So that's the case for taking up what is really an excellent, and absorbing hobby that will give you a lot of pleasure even when you're not actually participating in it. There are many ways of starting off without doing anything too involved. Improving the equipment supports, experimenting with different interconnects and speaker cables, optimising the mains supply, modifying equipment cases, cleaning media, the list is almost endless. Be warned though, this is a very addictive hobby as most of us already involved in it will reluctantly testify to!
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Buying components

For this section, I will have to confine my advice to buying components for those of you living in the UK. If anybody from another country wants to compile a similar section, I will be happy to include it here too.
The sad truth is that it is getting to harder to buy electronics components in the UK from the hobbyists point of view. The larger suppliers like Farnell and RS make things difficult with either minimum order requirements or expensive handling charges for small orders. Maplin, once a great source of everything for the electronics hobbyist has drastically cut its lines as it moves to selling ready-made electronics items and computer equipment.
So, here are the options:
  • Farnell - a large world-wide company. Usually better prices than RS. Minimum order of 20 UKP (before VAT). Large range and quick delivery. Request a (free) CD catalogue and you can browse at your leisure and even make up your orders offline.
  • CPC - a branch of Farnell aimed more at the hobbyist. Smaller minimum order quantities but higher prices and limited range. Orders over 30 UKP are shipping-free.
  • RS (formerly Radio Spares and not to be confused with the US company Radio Shack) - Another large company with a huge range of components.
  • Recommended by Chris Dunn in New Zealand as an excellent source of components with competitive prices and delivery charges, Element 14 could be worth checking out (Chris says that this company may be Farnell under a new name).
  • Maplin Electronics - still have some useful electronic components but watch out for shipping costs unless the order is over 30 UKP.
  • Cricklewood Electronics - a smaller company specialising in those harder-to-find parts like obscure transistors. No minimum order charge and they keep their shipping costs reasonable to.
  • Rapid Electronics - An alternative to Farnell and RS and very easy to find stuff too!
  • Audiocom - a small company specialising in the more exotic components but fairly expensive.
  • The Hi-fi Collective - another smallish source of hi-end components.
  • A UK source of audio capacitors.
  • Greenweld - offer surplus electronic items. Often worth a look but shipping costs will inflate prices on small orders.
  • PW Electronics - more surplus parts at very nice prices! Friendly service and only 2 shipping change and no minimum order!
  • Those of us in the UK can now order direct from Digikey who carry some parts not found at Farnell, RS, etc.
  • Ebay can be a very useful source of parts, particularly when you don't want to place a large order.
  • Of course there is a lot of useful stuff for the hi-fi DIYer on Ebay. Much of it is coming from places like Hong Kong, and as ever you have to be careful who you buy from. One seller that has some very nice products and reasonable prices, is the seller known as Geartown. I have bought from them and can recommend their friendly service. Delivery often takes only a few days and they take customer care very seriously!
  • Another Hong Kong supplier I have dealt with is VT4C run by a friendly guy called Chung who is also a keen hi-fi DIYer. He has collected together a mouth-watering selection of everything the DIYer could want and the prices are very competitive too. Ordering is easy. You select what you want, email him, and he replies with the total cost including shipping (don't forget to tell him where you live).
  • Blair Thompson's audio and electronics web site.
Somebody wrote to me from Malaysia suggesting that for you guys out that way, two reliable sources of components are Mouser and Jameco, both in the USA.

And some even better news!

I have been contacted by Richard Hutchinson of RSH Electronics with the following message:

I run a small electronic components company based in the Midlands, I keep a stock of all the commonly used bits and bobs like 555 timers, 741 op-amps, BC108s, 1N4148s - that kind of thing. If you want 1 resistor you can buy 1 resistor. I also do a range of bargain packs like 20x 8 Pin DIL for 1 and 1000 Carbon resistor selection packs for 4.99 There's no VAT to pay, and our postage is only 2.

Now if that's not good news for those who need the odd resistor or capacitor and don't want to place a large order with one of the 'big boys', I don't know what is! Richard is currently updating his site and working to produce a catalogue with more details of the items that he sells but if you need any more information, ask him and he will try and supply data sheets etc.
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Links


Audio Asylum. An audio discussion group.
An audio review magazine with discussion forums.
London Live Hi-fi Circle. An excellent UK hi-fi circle.
A very good source for audio links compiled by Andy Evans.
Useful reading and links at the DIY Audio Page .
There's plenty of useful technical information at the
ADIRE AUDIO site.
Not entirely in English, but a wonderful source of links, The Audionova site is a brilliant place to start searching for anything hi-fi related.
Richer Sounds - The UK's Hi-Fi, Home Cinema & Flat Panel TV Specialists!. Perhaps DIY isn't for you but you want a cost-effective hi-fi system. Richer Sounds have long supplied real hi-fi bargains and should be the first place that you check prices. Some of their budget stuff will respond well to tweaking and their own Cambridge brand has produced some quality hi-fi.
A truly comprehensive collection of audiophile related links can be found here.
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