Thanks and cheers to you all!
That schematic will work into 8 ohms, but a 4 ohm speaker will overload the amplifier chips.
I would suggest something like a TDA7294 board with an appropriate split power supply, or perhaps one of the many class D boards now on the market.
I did experiment with this circuit before and it fried after seconds under these conditions
But why is that? What info on datasheet should point that out?
TDA7294 seems good, claims about 60w a bit under my goal but still seems like my best choice for now.
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There is no easily available Class AB chip that will handle a 4 ohm subwoofer at 22V rails in bridged mode. You will need a minimum of 4 chips, in PBTL configuration, or a 'booster' type circuit with 1 chip per half - which might actually be unstable.
Most Class D amps should also be able to handle it, but most are single supply or need higher rails.
If its 4 cheap chips i might actually spend the time to do it, so what chips are we talking about? For example can i use TDA2040? Connecting outputs of amps together sounds risky, wouldn't i need to balance them somehow?
For example what do you think about this circuit?
More transparency in active speakers - part II - diyAudio
Do yo think this can supply significantly more power than TDA7294 so it's worth the complexity?
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Have you considered using class-D ? A TI TPA3255 can drive 2 ohms in mono mode to 600 Watts on a 50V supply.
It costs less than $11 in single lot from DigiKey and is not much bigger than a postage stamp and does not need a
huge heatsink due to the high efficiency. Seems like just the ticket for a sub in a car.
The higher efficiency lowers fuel usage and your carbon footprint and reduces climate change. OK that's probably BS.
G²
I liked TDA3255 but unfortunately it's not locally available and my only option is AliExpress to source that ic right now. But class-D sounds interesting, is there any other ics you can recommend? Maybe i'll get lucky and find them locally? 600w is overkill for me 150w is speakers max. And as long as its working stable i don't think mother nature would care for my sound system of all things
. It's cool to have a cool amp though
.
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With a +/-22V supply and a 4 Ohm speaker, LM3886 is your only chance without having to connect more ICs or channels in parallel. As stratus46 recommends, a class D amplifier seems more suited because you need quite some power, heating of the amplifier will be an annoyance and you only use it for low frequencies.
There are divided opinions on if class AB or class D sounds best from the mid-range and up. If it is about getting some bass-kick, I guess most agree that class D is it.
LM3886 is locally available for a reasonable price and seems like a good choice, only its output power rating falls around 40w which is low for my target but seems like the simplest way to drive my sub. Class-D also sounds like a good solution. Can you recommend any particular chip or board?
