Amplifier for subwoofer(s)

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I'm going to build a bridged 4-channel or stereo amplifier for my two subwoofers. Much power, but I don't won't PA - it has to be pure Hi-Fi.

I have been thinking about the LeachAmp, but I'm not sure how it will work with higher voltages than with the standard 2x40v transformer and in low impedance loads (4ohm subwoofer as bridged).

My transformer is 2kW 1x96v, which i'm going to split to 2x~45V - there's possible to lower this to 2x40V, but I'm much more interested to rise this as much it's possible.

Should I forget the Leach and move on to some better circuit (and which is?). What part in the Leach circuit is restricting the possibility to rise the driving voltage - main transistors? Which main transistors would be the best for power amplifier, keeping in mind they should sit without need to modificate (much) the circuit?

I have read that the Leach SuperAmp wouldn't be so "up-to-date" circuit. I would be very interested to here how to add more main transistor pairs to the basic LeachAmp circuit to get more stability to low impedance loads and of course how to rise the voltage durability, so that there's no need to move to SuperAmp. New main transistors have SOA about 80V 2.5A while the original had 50V 5A, does the other part of the circuit handle the "80V"? The problem is when adding driving voltage I lost in capability to drive in the low impedance loads. And that's needed to drive the 4 ohm subwoofer when the amplifier is bridged (the real load as seen by amplifier is dropping sure way under 2ohm).

I read that with newest modifications the LechAmp should drive the 1.3ohm load with it's full nominial power without the need of the restriction circuit. This might be enough for bridged amplifier driving 4ohm subwoofer with 2x40V transformer - or is it?

I'm newbie in amplifier section, but have been messing up with electronics for a while. I would be very thankful if someone could give some specific instructions to how add a pair or two main transistors to original LeachAmp circuit. And the possibility of rising driving voltage is also a little question-mark...

Teemu
 
Linn and Audio Physic are using parallel/bridged IC amps (TDA7293 - Linn, LM3886 - AudioPhysic) in their flagship semi-active loudspeakers to power their subwoofers. So... I guess if it works in 30000+EUR loudspeakers it's not bad solution and it would be much easier and cheaper to make than Leach.
 
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