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anyone help build a subwoofer amp?

  • 06-09-2009 8:50pm
    #1
    Closed Accounts Posts: 13 ✭✭✭ cyberbear


    hey guys,
    im tryin to build an amp!
    i picked up two 200 watt speakers! problem is i dont have an amp!
    i think it would be intersting to build one or two!
    anyone got any hints? ideas on how to go about it?
    any links to sites which could help?
    am i just starting too high? thanks a lot!

    speaker specs: 200w 4 ohm!


Comments

  • Registered Users Posts: 15,953 ✭✭✭✭ cnocbui


    http://www.diyaudio.com/

    I think it would be cheaper to buy an amp, if cost is a factor in your thinking about building one.

    Mains powered amps are usually rated for driving 8 ohm speakers, so a 100w amp should be all you require to deliver 200w to a 4ohm speaker.


  • Registered Users Posts: 6,159 ✭✭✭ ZENER


    cnocbui wrote: »
    http://www.diyaudio.com/

    I think it would be cheaper to buy an amp, if cost is a factor in your thinking about building one.

    Maplin do MOS-FET Amplifier kits up to about 200Watts The kits are cheap enough. The expensive bit is the power-supply and transformer
    Mains powered amps are usually rated for driving 8 ohm speakers, so a 100w amp should be all you require to deliver 200w to a 4ohm speaker.

    There's something wrong with that logic I think. A 100 watt amp > 8 ohm speaker will drive a 4 ohm speaker at higher power, but it's limited by the capacity of its power supply and the electrical characteristics of the output transistors. What you're suggesting is that a 100 watt amp in 8 ohms (3.5 amps approx) can then deliver 200 watts into 4 ohms (7.1 amps approx). I doubt it somehow ?

    Ken


  • Closed Accounts Posts: 13 ✭✭✭ cyberbear


    zener : you are sayin it is possible and worth while doin?
    cnocbiu: how much would an amp cost to buy for theese? how much to build? thanks!


  • Registered Users Posts: 6,159 ✭✭✭ ZENER


    A 200 watt Amplifier Kit is available for about 25 euro in Maplin in Blanchardstown SC.

    This is the trafo required.

    You'll also need a Bridge Rectifier and some large smoothing Capacitors and a substantial heatsink if you intend driving it hard.

    Also note that the RMS output is only 100W into 4 ohms and 70W into 8 ohms.

    Only you can decide if it's worth building, can you manage a soldering iron ? Do you have any experience of electricity or electronics ?

    Ken


  • Closed Accounts Posts: 13 ✭✭✭ cyberbear


    yes i can use a solder iron! ive done some work with earphones and simple circuits but im takin this to get experience! i can get help so i dont think it should be a problem in building it as long as the words arent to complicated! :P


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