subwoofer amplifier schematics?????

Flavio88 · 11th September 2005, 12:39 AM

Somebody have some schematics of a simple,high power(180w\4ohm or more) and reliable power amplifier for subwoofer use???
If possible, it does work with +37 0 -37volt power supply.

Thanks

jaycee · 11th September 2005, 01:27 AM

http://www.ampslab.com/c200.htm

You won't get 180W into 4 ohms with +-37V supplies though.

AndrewT · 11th September 2005, 09:07 AM

Hi,
you could build two 50w to 60w into 8r amps using +-37Vdc.
If you bridge them you MAY be able to get 180w into 8r.
The problem to overcome to achieve this is current delivery from both amps.
Let me explain. A 50w/8r amp should be able to give 90w/4r if built with a good PSU and a very good output stage.
A bridged pair will then achieve double power into double the load impedance. Thus you get 180w/8r.
However a good rule of thumb for designing an amp and it's PSU is to ensure it can safely deliver full load into a load impedance about half the speaker load. For a conventional amp this equates to safe power into 4r, no problem usually. But for a bridged amp each output stage thinks it is driving a load that is half the value actually connected across the outputs. This requires both amps to be safe pushing 180w into 2r (non reactive). At peak voltage (28Vpk) it is delivering 14Apk and the PSU must hold up while allowing BOTH amps to use 14Apk each.
Simpler and cheaper to use +-50Vdc to meet your requirement.

eugenio · 11th September 2005, 02:18 PM

try this class d 2 chips solution by national

http://cache.national.com/ds/LM/LM4651.pdf

or Elliott Sound Products sw amps

http://sound.westhost.com/project68.htm

or also thi s for bridging

http://sound.westhost.com/project3a.htm

good luck..
ciao e buon lavoro.
Eugenio

11th September 2005, 12:39 AM	#1
Flavio88 diyAudio Member Join Date: May 2005 Location: Roma	subwoofer amplifier schematics????? Somebody have some schematics of a simple,high power(180w\4ohm or more) and reliable power amplifier for subwoofer use??? If possible, it does work with +37 0 -37volt power supply. Thanks

11th September 2005, 02:18 PM	#4
eugenio diyAudio Member Join Date: Jan 2005 Location: firenze	try this class d 2 chips solution by national http://cache.national.com/ds/LM/LM4651.pdf or Elliott Sound Products sw amps http://sound.westhost.com/project68.htm or also thi s for bridging http://sound.westhost.com/project3a.htm good luck.. ciao e buon lavoro. Eugenio __________________ I love music

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11th September 2005, 01:27 AM	#2
jaycee diyAudio Member Join Date: Apr 2004 Location: Norwich, UK	http://www.ampslab.com/c200.htm You won't get 180W into 4 ohms with +-37V supplies though.

11th September 2005, 09:07 AM	#3
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	Hi, you could build two 50w to 60w into 8r amps using +-37Vdc. If you bridge them you MAY be able to get 180w into 8r. The problem to overcome to achieve this is current delivery from both amps. Let me explain. A 50w/8r amp should be able to give 90w/4r if built with a good PSU and a very good output stage. A bridged pair will then achieve double power into double the load impedance. Thus you get 180w/8r. However a good rule of thumb for designing an amp and it's PSU is to ensure it can safely deliver full load into a load impedance about half the speaker load. For a conventional amp this equates to safe power into 4r, no problem usually. But for a bridged amp each output stage thinks it is driving a load that is half the value actually connected across the outputs. This requires both amps to be safe pushing 180w into 2r (non reactive). At peak voltage (28Vpk) it is delivering 14Apk and the PSU must hold up while allowing BOTH amps to use 14Apk each. Simpler and cheaper to use +-50Vdc to meet your requirement.