Want to build a crappy 50W max mono amp. ideas?

[Zemo]

Hey guys, I want to build an amp to power this: http://www.partsexpress.com/pe/showd...number=299-028

I'd plan on going stereo in, mono out, and straight to this. It only need 50W of power at max, and it really doesn't have to sound good....it doesn't make sound!

What's the chiepest possible amp for this kind of thing?

Maybe skip the powersection and buy a wallwart that outputs maybe 20V DC?

[ashok]

You could use a NPN/PNP power BJT pair running in class B or on the verge of Class AB ( base to base voltage of 1 volts or less).
Connect direct to the power amp output ( speaker leads ) and with split (+/-) supplies. A wall wart's voltage might drop rapidly , especially at LF , and produce hardly any power into the "bass shaker". Only hitch here is that you might not be able to set the level on the bass shaker independant of the volume level.
That can be arranged with some extra circuitry.
Cheers.

[Zemo]

wow, that is probably very helpful....but about 95% of it is over my head....I understood this part:

A wall wart's voltage might drop rapidly , especially at LF , and produce hardly any power into the "bass shaker".

Hope you wouldn't mind explaining a little more?

what is a NPN/PNP power BJT? what is class B? what is class A/B?

and yes, I'd need to be able to control the level independant of other variables.

schematic? detailed description? anything? thanks!

[tpenguin]

I would recommend an amp based on the LM3886, with cheap components used throughout. I would use the 48VCT 3A transformer PE sells, at least 2000uF per rail, and set the gain to your liking. I don't think clipping should be too much of a concern with a "tactile transducer," but I'm not really sure. I'd say for all the parts put together, you're looking at about $50. For cooling the chip, a passive heatsink from a slot-1 pentium 2 or 3 would work quite well if you can find one cheap or salvage it from an old computer.

[r0cket-]

Originally posted by Zemo
What's the chiepest possible amp for this kind of thing?

Well, not to step on your DIY bug, but you'd probably be better off just finding an old receiver at someone's garage sale for $5 and using that.

[meat]

BJT is a bi-polar transistor.

NPN/PNP refers to the type of transistor it is or how the transistor behaves.

better description

web site explaining different classes of amps

[peranders]

Maybe a Gainclone amp built by LM3886, 68 watts out.

What is your budget?

[Hybrid fourdoor]

Originally posted by r0cket-

Well, not to step on your DIY bug, but you'd probably be better off just finding an old receiver at someone's garage sale for $5 and using that.

The only problem with this is that not many recievers (old at that) have a "Main Amp In". I suppose that plugging the Preamp out into say, CD, might work, but you may clip the reciever if the input level gets too high. Adding a resistor could lower the input level, then just turn the volume up (on the shaker reciever) to compansate.