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how do i build an amp that is very complex and still have it simple to build and cheap? Answered

I need to build a complex amp for cheap and as simple as possible
i need it to
-run speakers at differant ohms safely
-have left and right channels
*-have little distortion
-have 3 inputs
-have outputs that can run at least 6 speakers off of each channel
-have volume control
-off/'on switch
*-portable and have to run of of 9V batteries (as many as it takes)

so how can this task be compleated
could someone help design this?


a complex but simple to build amp?
I believe that's called an oxymoron.

Quite true but what I meant by that was an amplifier tht has a high wattage and gain and volume controls

Complex AND simple? How much skill do you have with building electronics (e.g. what's the most complex thing you made that worked)? L

umm i built a surrond sound set by putting peakers to gerther in a parrallel circuit it work for some time them the amp blew out but i mostly work with leds and other simple circuits

This could be tricky. You might find it easier to re-use / modify an old stereo unit instead. These are things you can find second-hand without much trouble. L

what if i just use 2 amp-chips (one for left + and right +) would that work?

Amp chips? These are usually stereo-modules, usually heat-sunk. As I said: old stereo, you might find one for nowt.


yes isnt what the LM386 is for? its just a small amp that amplifies the signal then use the LM741CM to drive the speakers? http://www.radioshack.com/family/index.jsp?categoryId=2032279&s=null would that work or am i way off?

Yes you could use two of them, but I'd thought you wanted something bigger and more powerful. I've got at least 3 stereo amplifier modules kicking about from old electronics e.g. an STK4132.


That one was out of an old Technics unit, it's pretty good. However, I took it apart because it stopped working properly. It may be that the STK4132 is "knackered" or it's something else (I don't know)


It might help if you described what you're trying to accomplish rather than spelling out the specs. That would give folks more room to suggest practical alternatives. The 9V requirement is the one that's going to kill you, I think. Unless you have a frakkin' huge pile of 9V's, I don't think you're going to get low distortion at any significant volume for any significant length of time. Number of speakers does matter as much as the total impedence number, since it affects how much power produces how much sound at each of those speakers... and thus how much volume you can get before distortion becomes obvious. It also affects how even the volume is from speaker to speaker.

really if i can get an amp that has volume control/2 stereo chanels/ and off/on i will add the inputs with a selector switch and i will have to settle with either 6 ohm speakers or 8 ohm which ever i have more of. then could this be possible

what im triing to do is create an amp that has sound all around the room at once and i want to plug my guitar my tv and my computer in the amp i want the mono guitar to come out all speakers and i want this device to be easily moved from my room to the garage to outside and anywhere else with a volume

your requirements are mutually exclusive!

i put * next to ones that could change or even be excluded but that is waht needs to haapin

Rick Harris is right. You are asking the impossible, and you're asking someone else to do it for you (for free), instead of doing it yourself. You get what you pay for, and cheap does not equal complex.

Running speakers with different ohm ratings is going to be expensive. To do that safely you need an output transformer that has multiple windings that you can wire to different jacks.  Those transformers start at about $45 US and you need two of them.  You can usually run 4 ohm or 16 ohm speakers on an 8 ohm amp if you don't run it wide open.

Left and right channels means look for stereo.

Less distortion means more money.

You can add as many inputs as you want it's just adding a jack, capacitor and resistor or a mixing circuit.  That's up to you.  If you're going to build the amp then I'd get it working on one input and either use a cheap mixing box to feed the amp or add the inputs.

It doesn't matter how many (basically) speakers you put on the output as long as you wire them so that the ohms add up right.

All amps should have volume and on/off controls.

Portable is easy to get but you might have to use something other than 9 volts.


You didn't say how much power you want to have.  If you want to run something off 9 volt batteries look at these amps.  They only have 1/2 watt but some of them sound very good.

If you want more power and a better sounding amp, look for a kit.  Here is an example of a pretty good sounding, high power amp.  It's based around one of the more powerful "amp in a chips".  It's got most of your desires and you can add the inputs.  And the price is right.  You could'nt build one for twice that if you DIY.