Surround Amplifier

soundNERD · 10th July 2004, 12:17 PM

I have always wanted to build a 5-channel surround amp. Now I think I'm ready to finally start. But, I need some reccomendations on what chip to use. I want close to 200W per channel so it has plenty of power to keep up with the explosions in movies. The front needs to be able to drive 2 ohm speakers and the center and rear are 8 ohm. I was originally thinking of using the bridged OPA549 PCB design I already have. But, to drive a 2 ohm it would need 3 of those bridged boards paralleled together. So 6 boards for the front and 3 for the rest. That's 12 chips in the front and 6 in the back or 18 chips total. I would like to use less than that if possible.

What chip is simple enough to use and to make the boards for them myself, yet also provides enough power and is able to drive demanding speakers? Should I just go with the opa549 and make that many boards?

Tsanford · 10th July 2004, 12:51 PM

IMHO, 2 ohm loads are a tall order.

If it were me, I would reconfiguring the front 2 speakers say for at least 4 ohms. This would save you a lot of chips and troubles.

Honestly i've never made a chip amp (yet), but from what I have read here on the forums. A 2 ohm reactive load would possibly make the protection circuitry on the chips kick in once they got good and hot, as the load can go much lower than nominal.

I am just getting into this again after 15 years so consider this a newbie opinion at best.

Good luck to you.

soundNERD · 17th July 2004, 02:44 AM

is anybody here?

please recommend a good chipamp for this task.

mrrao · 17th July 2004, 06:10 AM

use transistor .

soundNERD · 17th July 2004, 01:25 PM

too complicated...

Well, actually, is it possible to use a single high power transistor? I have some On Semiconductor MJ15003 and MJ15004 High Power Transistors. How much power can I get using those? And, how would I use them?

mrrao · 19th July 2004, 02:31 AM

yes very complicated.
because high voltage.
abvert smoke out.

B.I.G · 19th July 2004, 02:27 PM

HIGH VOLTAGE ====> HIGH POWER

YOU can get about 150W/4ohm with one pair of mj15003/4

tiroth · 19th July 2004, 02:30 PM

Really? I thought that was way outside SOA for a single pair.

soundNERD · 20th July 2004, 02:02 AM

could that pair of those transistors drive 2ohm, even 1ohm?

Would somebody mind helping me build this by designing a schematic?

soundNERD · 22nd July 2004, 01:25 AM

anybody??

10th July 2004, 12:17 PM	#1
soundNERD diyAudio Member Join Date: Sep 2003 Location: Illinois	Surround Amplifier I have always wanted to build a 5-channel surround amp. Now I think I'm ready to finally start. But, I need some reccomendations on what chip to use. I want close to 200W per channel so it has plenty of power to keep up with the explosions in movies. The front needs to be able to drive 2 ohm speakers and the center and rear are 8 ohm. I was originally thinking of using the bridged OPA549 PCB design I already have. But, to drive a 2 ohm it would need 3 of those bridged boards paralleled together. So 6 boards for the front and 3 for the rest. That's 12 chips in the front and 6 in the back or 18 chips total. I would like to use less than that if possible. What chip is simple enough to use and to make the boards for them myself, yet also provides enough power and is able to drive demanding speakers? Should I just go with the opa549 and make that many boards?

10th July 2004, 12:51 PM	#2
Tsanford diyAudio Member Join Date: May 2004 Location: Atlanta Georgia Area	rough load..... IMHO, 2 ohm loads are a tall order. If it were me, I would reconfiguring the front 2 speakers say for at least 4 ohms. This would save you a lot of chips and troubles. Honestly i've never made a chip amp (yet), but from what I have read here on the forums. A 2 ohm reactive load would possibly make the protection circuitry on the chips kick in once they got good and hot, as the load can go much lower than nominal. I am just getting into this again after 15 years so consider this a newbie opinion at best. Good luck to you.

19th July 2004, 02:27 PM	#7
B.I.G diyAudio Member Join Date: Mar 2004 Location: Home	HIGH VOLTAGE ====> HIGH POWER YOU can get about 150W/4ohm with one pair of mj15003/4 __________________ B.I.G

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17th July 2004, 02:44 AM	#3
soundNERD diyAudio Member Join Date: Sep 2003 Location: Illinois	is anybody here? please recommend a good chipamp for this task.

17th July 2004, 06:10 AM	#4
mrrao diyAudio Member Join Date: Jul 2004 Location: shenzhen city	use transistor .

17th July 2004, 01:25 PM	#5
soundNERD diyAudio Member Join Date: Sep 2003 Location: Illinois	too complicated... Well, actually, is it possible to use a single high power transistor? I have some On Semiconductor MJ15003 and MJ15004 High Power Transistors. How much power can I get using those? And, how would I use them?

19th July 2004, 02:31 AM	#6
mrrao diyAudio Member Join Date: Jul 2004 Location: shenzhen city	yes very complicated. because high voltage. abvert smoke out.

19th July 2004, 02:30 PM	#8
tiroth diyAudio Member Join Date: Dec 2001 Location: Pittsburgh, PA, USA	Really? I thought that was way outside SOA for a single pair.

20th July 2004, 02:02 AM	#9
soundNERD diyAudio Member Join Date: Sep 2003 Location: Illinois	could that pair of those transistors drive 2ohm, even 1ohm? Would somebody mind helping me build this by designing a schematic?

22nd July 2004, 01:25 AM	#10
soundNERD diyAudio Member Join Date: Sep 2003 Location: Illinois	anybody??

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