Homebrew Amp?

[E]

Hey, i'm new to the guitar in general but in hopeful research for my first guitar buy i've come across you guys when looking at how to make an amp. Clearly enough people have done it, but there doesn't seem to be any 'definitive guide to everything' that a lot of other hobbies have on the internet. So what do i need to know? I've managed to deduce that it consists of three main parts; the preamp, the power amp and the speaker (which seem to be conveniently on Maplins) but other than that i'm pretty much clueless as to what i need to do. So can you point me in the right direction? Cheers

[J M Fahey]

Hi E.
Go step by step.
Read about and build an LM386 amplifier, such as the Ruby, that will give you a lot of hands-on experience.
Later build some of GGG's or other sites pedals, and use them as preamps for your Ruby.
You can then upgrade to some TDA 2003/2006/2030/2050 amplifier, with increasing power outputs, from 10 to 30W.
You can then upgrade to an LM1875 or LM3886 amp, with very loud 50W RMS, enough for any practical stage use.
You will learn, hands-on, along the way.
Once you feel strong enough, you can buy por peanuts or get for free some troubled or dead amplifier and mount your own concoctions into its chassis and cabinet, using its power transformer and speaker if suitable, and end with a very good looking amp.
Meanwhile, download the excellent Teemuk's book on SS amplifiers, but read it slowly, it contains tons of info.

[E]

Woa, that's wierd. First time i've used this username...

Anyway, thanks for the info - would i be right in assuming that the Ruby would work without a preamp? I still seem to be encountering the same problem (probably down to my rubbish googling skills) that i can't seem to find anything that actually tells you what to do, is there or is it an experience/knowledge based thing?

[Minion]

Well the first thing you gotta learn even before building anything is how to read a schematic and learn what all the symbols in a schematic mean , then you got to learn the basic uses for the most common components like resistors, capacitors, diodes , transistors , IC"s ect ...... A simple kit for a Pedal is a good start especially one that has documentation that not only explains how to build it but also explains how the circuit works , PAia kits are good that way and they have so good designs which you can learn a lot from building but are a bit too expensive in my opinion .....
There are also some good cheap kit on e-bay , they are short on documentation but high on Value ......

One of the most Valuable things is to have a friend who knows his/her electronics who can help you understand things and to bounce ideas off of , which is one thing I never had ....

I personally spent over 6 months reading and doing research before attempting my first project , which by the way was a Simple Microphone preamp (Green Pre) which turned out to be a lot more difficult than I first thought it would be , I had to etch my own Circuit boards and source my own parts and i knew very little but the project was a success but not very pretty .... That was about 5 years ago and since then I have built Most of the Mic preamps in my Studio , Built my studio monitors , built a couple simple EQ"s and designed a simple active electronics circuit for bass and guitar which I have built and sold close to 50 of to friends and other musicians, at $35 a pop I have made a few bucks at it , Ive also built several guitar and bass amps from 15w up to 100w, Many sucked but every new one is better than the old one .......


Good luck

[tonyharker]

Why not try a noisy cricket?  There should be enough info here < http://www.beavisaudio.com/projects/NoisyCricket/#Intro >  to tell you what to do.

[E]

Why not try a noisy cricket?  There should be enough info here < http://www.beavisaudio.com/projects/NoisyCricket/#Intro >  to tell you what to do.

Would that be a better option than the Ruby? Would it be possible to do with an inbuilt speaker? And how are those ultra simple smokey tone amps they have at the bottom?

Is there a guide to all the terms i should know somewhere? I reckon i could read the circuit diagrams - it's not too long since i did it in school.

Oh, and if it's not too much to ask could somebody have a look on Maplins to see if they have everything required? Only i can get a discount there... what sort of tools do i need? Obviously a soldering iron which i've been meaning to buy for ages but other than that i'm not entirely sure.

Thanks for all your help, i appreciate it

[pyromaniac_]

Why not try a noisy cricket?  There should be enough info here < http://www.beavisaudio.com/projects/NoisyCricket/#Intro >  to tell you what to do.

Would that be a better option than the Ruby? Would it be possible to do with an inbuilt speaker? And how are those ultra simple smokey tone amps they have at the bottom?

Is there a guide to all the terms i should know somewhere? I reckon i could read the circuit diagrams - it's not too long since i did it in school.

Oh, and if it's not too much to ask could somebody have a look on Maplins to see if they have everything required? Only i can get a discount there... what sort of tools do i need? Obviously a soldering iron which i've been meaning to buy for ages but other than that i'm not entirely sure.

Thanks for all your help, i appreciate it

The Noisy Cricket is basically the Ruby amp with some modifications. It got a tone control and an grid switch which the Ruby doesn't, but except that they are about the same, and in my opinion they also about sound the same. Which one that is best it's up to you. With the noisy cricket you could probably get more different sound out of it, but require more components. And yes it could done with an inbuilt speaker as well.

The smokey amp looks a lot like the Little Gem amp, and would probably sound about the same. Check out this thread; http://www.ssguitar.com/index.php?topic=1456.0 or www.runoffgroove.com for some soundclips of the Ruby except you haven't heard it before.

Some people doesn't like the smokey/little gem amp because the input impedance of the lm386 chip is too low for guitar. And therefor the the noisy crikcet or ruby amp which got an FET buffer in front of the lm386 may sound better, more "spark" in the sound and so on, but personally i think the Ruby/Smokey amp sounds satisfying

[E]

Okay, thanks. I might have a go at both seeing as the Smokey can fit into a pack of playing cards sized enclosure.

When building a full setup do you have to match the maximum output of the amp circuit to the maximum output of the speakers? Also, how would a 'full range' setup cope? Say with a woofer, a loudspeaker or two and a tweeter. Or does it have to be just a woofer? On the subject of drivers why aren't horn speakers used? They should be quite efficient...

[E]

You reckon one of these 386 amps would drive 3W into 4 Ohms? Just i pulled two of these "ST 77FS-AN" drivers from an old set of PC speakers, seems a shame to waste them. Would they sound any better or worse than a 1W 8 Ohm Mylar driver (what i was planning on using). They're about 7.5cm in diameter.

Also, anybody have any idea where i can find enclosures in the UK? I'm having a bit of trouble... thanks

[joecool85]

You reckon one of these 386 amps would drive 3W into 4 Ohms? Just i pulled two of these "ST 77FS-AN" drivers from an old set of PC speakers, seems a shame to waste them. Would they sound any better or worse than a 1W 8 Ohm Mylar driver (what i was planning on using). They're about 7.5cm in diameter.

Also, anybody have any idea where i can find enclosures in the UK? I'm having a bit of trouble... thanks

I would use the computer speakers, I have had great luck with them on several Little Gem builds.  As far as enclosures, the sky is the limit.  I have used a small wooden box from a craft store, a computer supply (gutted first) and a clip-on pocket radio for cases for these small amps.  I have an old router that doesn't work that is going to be one eventually, as well as some old dead computer speakers.

[J M Fahey]

Tupperware type plastic food containers are a goldmine.
Cheap, easy to drill and cut, available in any size, translucid to show off your skills 8|, what else can you ask for?
As another option, check "Scarface" here.
As yet *another* option, IKEA shops  are interesting too.
Check the SSGuitar contests (hint hint)

[rowdy_riemer]

Like Joe, I just recently used an old ATX power supply housing. I have no idea about the UK, but here in the U.S., radioshack sells a cool little aluminum enclosure. I've used them for a Ruby amp, a couple of preamps, and for my "Proto Box" (has a small solderless breadboard inside and various holes drilled for pots/jacks). I'd be willing to bet similar enclosures are available at any electronics supply store. These ones on the maplin site, http://www.maplin.co.uk/Module.aspx?ModuleNo=1728, look similiar, but if you're ordering enclosures, I guess there are some better ones.