Subwoofer Chip Amp - Decision

[hackspider]

Hi together,

The target sub woofer is the Mivoc AWM 124 (4Ohm). The rail voltages are +-35VDC and the goal is something around 100W. First I thought about using a bridged version of the LM7294 but the datasheet mentioned that in bridge mode the load impedance must be equal or higher than 8Ohm. So I need suggestions which (chip-)amp to use with 35VDC, about 100W and is capable to drive 4Ohm loads?

Parallel LM3886 (PA-100) or LM4780 in parallel config maybe?

Another question is: Do I have to build a low pass in front of the sub woofer amp? or do I amplify the whole spectrum?

To give a overview, this is what I'm planning:
5.1 Surround amplifier based on LM3886. All channels (including sub) shall be driven by a single toroid transformer (800VA 25VAC-0-25VAC -> ~35VDC). Every channel has its own PSU (rectifier/caps).
Do I have to consider something driving 6 PSUs at one transformer?

Best regards
hackspider

 

[AndrewT]

build a single chipamp for the +-35Vdc supplies and test the 4ohm bass speaker on it.

 

[richie00boy]

If the .1 output is from a decoder then it should be already filtered for use with movies.

 

[bimo]

Hi together,

The target sub woofer is the Mivoc AWM 124 (4Ohm). The rail voltages are +-35VDC and the goal is something around 100W. First I thought about using a bridged version of the LM7294 but the datasheet mentioned that in bridge mode the load impedance must be equal or higher than 8Ohm. So I need suggestions which (chip-)amp to use with 35VDC, about 100W and is capable to drive 4Ohm loads?

Parallel LM3886 (PA-100) or LM4780 in parallel config maybe?

Another question is: Do I have to build a low pass in front of the sub woofer amp? or do I amplify the whole spectrum?

To give a overview, this is what I'm planning:
5.1 Surround amplifier based on LM3886. All channels (including sub) shall be driven by a single toroid transformer (800VA 25VAC-0-25VAC -> ~35VDC). Every channel has its own PSU (rectifier/caps).
Do I have to consider something driving 6 PSUs at one transformer?

Best regards
hackspider

Almost all comercial AV receiver use one power supply to drive multi channel amplifier. Crosstalk is good if designed correctly (components layout and grounding).

You should consider class D amp for sub woofer. I think it is difficult for LM3886 to drive 4 Ohm using +-35V power supply. You can parallel LM3886 if you insist to use it.