Amplifier idea..

Those "killer" puny speakers won't have much output level, and their frequency response graphs disagree with each other and with the printed spec's. How can a 2" speaker that resonates at 150Hz in free air, have a response to as low as 80Hz in a box?
One response curve shows probably a completely different speaker with a wide, smooth response, but the other response curve is all over the place!

I think that Maplin has things all wrong and backwards. They talk about their amplifier module that has a "peak" power of 18W into a 4 ohm speaker. That's only 9W RMS at only one frequency, and probably with a horrible amount of overdrive distortion. It might be 6W RMS or less into a 4 ohm speaker, from 20Hz to 20KHz, at reasonably low distortion.

Maplin also talks about powering the amplifier with a lower supply voltage and a higher load resistance to produce even more output power. Wouldn't that be nice. If you used no supply voltage and a very high load resistance its output power would be infinite!

Yeah, I noticed that :lol:

Dunno why its like that. The thing i'm after is more or less a much better version of this sort of thing:

http://i.i.com.com/cnwk.1d/sc/20649051-2-200-0.gif

Obviously, it'd be bigger, and much heavier, but it'd sound a lot better I reckon too. Already got a seperates Hi-Fi for proper listening, this is to go in my bag, though it looks like it may cost £100 :shock: , and if you right about those amps, then it would'nt be worth it at all.

Re. watts "r.m.s." again.

https://www.davidbridgen.com/watts.htm

David Bridgen said:

Re. watts "r.m.s." again.

https://www.davidbridgen.com/watts.htm

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And it's still irrelevent again!.

Why?

David Bridgen said:

Why?

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Because it's commonly understood as the only accurate way of giving amplifier power ratings, it's easily checked, with very simple test equipment - and it's EASY to understand.

I read your article a while back, and it's basically a discussion of semantics, not a discussion of the actual technique - just that you disagree with the terminology!. You may very well be correct?, but the term has been used for well over half a century and is perfectly acceptable to almost all the world.

I see no point in keep posting the address of your article, learned or not?, when it's only going to confuse the issue?.

Ok, Nigel, I just wondered why you objected.
I shall bear your comments in mind.

Dr.EM said:

Hi. This is a schematic for a bridge amplifier of power 16w, from the web.

It doesn't actually say what the ICs are, but I couldnt help thinking they looked like 386s.

I know they're not, but could you use 2 386 amps in a bridge like this to output more power than one by itself?

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Hate to bring up an old thread, but I was on google searching for some info on bridged lm386s and came across this. The schematic the OP posted is for the lm383, I know it well.

You can easily bridge the lm386, as shown on runoffgroove.com, look at the littlegem mkII.

Interesting this should come up. I did actually try my orginal arrangement with pennies as heatsinks. It worked, with a small increase in volume, the pennies got very hot, chips survived though. Not very practical, but I wanted to know what exactly would happen.

Most audio high-power amp ICs are idiot-proof. They shutdown when they get too hot. NOT A GOOD THING TO HAPPEN IN THE MIDDLE OF DOING A GIG.

TI has a tiny little class-D power amp IC. It is rated at 240 Whats.

audioguru said:

Most audio high-power amp ICs are idiot-proof. They shutdown when they get too hot. NOT A GOOD THING TO HAPPEN IN THE MIDDLE OF DOING A GIG.

TI has a tiny little class-D power amp IC. It is rated at 240 Whats.

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Right...but I don't see a lm383 making it to a gig lol.

joecool85 said:

I don't see a lm383 making it to a gig lol.

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It hasn't been made for 11 years, it's retired like me.

What, the lm383? Only sort of. You can still find them at some places, and besides, you can use TDA2002 chips, they are pretty much identical.