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Registered Member #152
Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384
well, I need a low-voltage audio amplifier IC that can make nice loud sound with 5-6V in. I tried lm386 and tda2822m (bridge configuration), but none of these has enough output power for me (both have about the same power). The IC should be preferrably cheap (and have little external components, but this is not requied) and work well with 8ohm speaker. I think the bridge configuration is the way to go - is it possible to bridge two lm386's? Any ideas?
Registered Member #152
Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384
I think I found a nice amplifier IC: the tda7052 claims to have an output power of 1.2W with 6v supply voltage iinto 8ohm speaker and requies no external components, except it costs 5 times as much as lm386, it looks promising and I'll give it a try.
Registered Member #162
Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140
At low power the speaker sensitivity seems more important than the amplifier power, e.g. cheap speaker 80 dB SPL 1W 1m, efficient economy speaker 96 dB spl 1W 1m
Registered Member #152
Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384
Simon - the problem here is the available voltage - 4 AA cells and preferrably rechargeable (so thats only 5 volts).
Sulaiman - good point, the speaker I have is from old TV and is the most efficient one I have, but it is not making 90db with 1/4w for sure. I need the amplifier for portable battery-powered speaker (for my mp3 player) so the speaker should be small -> not very efficient
Registered Member #89
Joined: Thu Feb 09 2006, 02:40PM
Location: Zadar, Croatia
Posts: 3145
You could use a sall boost converter to boost battery voltage to something more. You should be able to find some of national's switchers around, or sample them.
They usually require 3 external components + pot if you wish to reuglate the voltage.
Or, you could use more batteries, maybe two 9V's iin series.
Registered Member #162
Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140
With a 5V power supply a 'perfect' single-ended amplifier could give 1.77 Vrms which is 0.39Wrms into 8 Ohms, 1Wrms into 3 Ohms. A 'perfect' double-sided amplifier could give 3.54 Vrms which is 1.56 Wrms into 8 Ohms, 4.17 Wrms into 3 Ohms REAL amplifiers will not do nerly as well.
Rechargeable AA cell can give up to 5A @ 1V = 5W per battery So a battery of 4 AA cells could give up to 20W (for a few minutes) So I'd consider a small invertor and PA ic like TDA2040 (one of my favourites, usually available on eBay)
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Audio amplifier IC
