Portable Amp

[tommy24]

Hi,
I'm totally new to building guitar amps, and i've challenged myself to building a small portable guitar amp. I have a basic knowledge of electronics, but i was wondering if anybody could direct me on where to start. I would ideally like to design the schematic my self, does anybody know of any usefull books or schematics to have a look at to get an idea of how to approach this project and how to get started.

Any help would be much appreciated.

Tom

[J M Fahey]

Hi Tommy.
Google "Ruby amplifier".
It's a great project to start with.
Our friend here, Sergscar, has built a very nice one, the "Scarface" , search it in ssguitar, that will give you some ideas.
Post what you build or any doubts.
Juan Manuel Fahey
EDIT: I've found it
http://www.ssguitar.com/index.php?topic=1091.msg6693;topicseen

[tommy24]

Thanks for the reply. The 'ruby amplifier' looks like an excellent place to start! Sergscar has done an excellent job of making one. I will have a go at making one myself. Il post any pictures of progress or problems i have.

Also could you recommend any jack sockets to use on the project, am i right in saying i require a stereo socket?

The help is very much appreciated. Thankyou.

Tom

[joecool85]

Thanks for the reply. The 'ruby amplifier' looks like an excellent place to start! Sergscar has done an excellent job of making one. I will have a go at making one myself. Il post any pictures of progress or problems i have.

Also could you recommend any jack sockets to use on the project, am i right in saying i require a stereo socket?

The help is very much appreciated. Thankyou.

Tom

Actually, you will want a 1/4" mono jack for your guitar amp.  Good luck. 

btw, I've had great luck running LM386 amps off as little as 4.5v (3 AA batteries).  But they work well with 9v too.  The nice thing is you don't need to change the amp at all to work with whatever voltage.  Just don't go higher than 12v.

[tommy24]

Great, I have been looking at the schematics for the ruby amp and I think i will be Ok with most of it. The only part i think i will struggle with is connecting the 1/4" mono jack socket to the circuit.

Ive tried to attatch the circuit below. My understanding is, there is two connecting prongs on a 1/4" mono jack socket. How do i connect the socket to this circuit.

Many Thanks

Tom

[Brymus]

The tip will connect to the "IN" of the circuit.
The sleeve will connect to the "ground" of the circuit.
have fun

[tommy24]

Hi guys,

I got the 'ruby amp' working! I am very pleased with the results. Firstly i would like to say thankyou for your help and advice.

Secondly I was wondering if anyone could advise on a reasonably priced 3 inch speaker. The one i have used is very cheap, and not of great quality!

Once i have a built the cab i shall post some pictures for all to see.

Thanks

Tom

*8 ohm speaker*

[J M Fahey]

Avoid "modern" cloth/foam/rubber edge spekers, try to get an old speaker , all plain paper cone, pulled from a TV or a car radio speaker, the cheapest radio around.
You don't want a speaker that expects to be driven with 30 to 200W, but one that had to sound as loud as possible with a 1 to 5 watt amp.
Juan Manuel Fahey

[Brymus]

I second what JM said the best SMALL spkrs for a Ruby have been ones pulled from TV
or other AV speakers.
And trust me I have tried several dozen different kinds.
The 5" Jensen Mod sounds good,and just about any 12" guitar spkr sounds fantastic with the Ruby.
PC powered Spkrs dont sound as good as a cheapo TV spkr though,I scrapped some square spkrs from a TV they sounded really good.
Hit your thrift shops, ask friends for dead TVs (awesome for salvaging other components too)
Or dumpster dive...

[tommy24]

Thanks for the advice on the speaker.

I have now completed the circuit and am in the process of building the cab. I will post pictures when complete.

My electronics theory is basic. I am very intrigued in the theory behind the circuit, would any one be able to give me a run down of what is going on in the circuit diagram in relation to the resistors and capacitors.

Any help would be much apreciated!

Tom