Does anyone know a bridged design for 12v rails?

[mpmarino]

Hi!

I'm putting together a high efficiency speaker system. Nothing drives me crazy more than AC hum. When you are using ~107dB altec drivers AC hum is hard to avoid

This whole thing is just a crazy idea

I am considering putting together a 12v+12v battery plant.

I wanna run the horns on a Pass mini A with 12+12 rails (total 1.5A draw). This should give me ~7-8 watts on a 107 dB horn. adequate IMHO.

The woofer is not yet specified but I expect to use something around 95-97dB. I'd like to find a nice sounding bridged solid state AB design to get the most out of the rail voltage of 12+12.

Is it possible to get decent power out of such low rails - that sounds nice? If so, could you point me in a direction.

Thanks a lot

[Bone]

Why don't you bridge a pair of LM1875s. This will give you about 15/16 w into an 8 ohm load at 12-0-12. It is not advisable to use a 4 ohm speaker however as you will overload the chip.

[mpmarino]

Thanks very much for the suggestion Bone. However, those big bugs just don't do it for me for some reason. Also, one of the woofers I'm looking at happens to be 4ohm - so......??

[AndrewT]

Hi,
there is a bridged ClassA amp somewhere on this site.
It is from a recent magazine article. One of the designers regularly posts here. I seem to recall rails around 20V. It may work at lower voltage.

BTW,
a CRC or CLC supply removes much of the mains hum/buzz.
You should not need to go battery power to eliminate hum.