1kW MOSFET amplifier - Page 5

AudioFreak · 21st January 2002, 02:19 AM

PassFan,

The amp is Class B or AB so will not have much in the way of quiescent dissipation........

Also the supply is transformerless and each 900W amp will have a seperate power supply .....

blmn · 21st January 2002, 02:20 AM

I think GRollins has made something like a watercooled amp.

Kilowatt · 21st January 2002, 07:55 AM

Actually, it will have one power supply for all 8 channels. It will have a 60A breaker as an on/off switch, 4 150A discrete rectifier diodes, at least 8 200V, 31,000uF filter caps (not much for a brute like this, I know, but it will have a high PSRR, and besides, those caps are huge and expensive), smaller electrolytics, film caps, two MOVs, 20W bleeder resistors (I'd hate to see those caps discharge into a screwdriver!! There wouldn't be a srewdriver left, I'd be seeing spots and have a ringing in my ears for a week!), and possibly two big inductors mounted in a compartment under the rest of the chassis.

I wonder how much tubing I'd need in the heat exchanger for this thing?

AudioFreak · 21st January 2002, 09:42 AM

thats not gonna be anywhere big enough for this amp kilowatt.. on transients this amp is gonna load down like crazy if it doesnt have heaps and heaps of low resistance capacitance in the power supply and because all channels will peak @ the same time, the peak current draw will be in excess of 100A

Jeremy_Wolf · 21st January 2002, 10:18 AM

KiloWatt, I don't know if anyone else has asked this exactly, but what are you going to use this thing for?? Simulating earthquakes, producing 5 hz tones at 140 db? This is a serious amount of power. Of course you could just be doing it for fun which is a good enough answer for me. But if you really need that much power, wouldn't it be cheaper to buy a comercialaly made amplifier setup? I know that a crown ce2000 is rated at 975 watts/channel into 2 ohms and they only cost about 550. Get 4 of these and you have your power requirements, it will only cost 2200 dolars for all 8 channels, all of the protection circuitry is built in, all of the cooling is built in, and to top it all off, there is a warrenty and they only wieigh about 40lbs each.

Not that I want to put a damper on the DIY spirit. Sometimes it is cheaper and wiser to go comercial. It's like designing a robot that can clean dishes when there are 200 dollar dishwashers for sale in every department store. But if this is a just for fun project, then good luck and take plenty of pictures for us all to see.

AudioFreak · 21st January 2002, 01:19 PM

the problem with the above mentioned amp is that it produces 975W into 2ohms.... Kilowatt needs that kinda power into a 12ohm load.

Kilowatt · 21st January 2002, 08:56 PM

Also, the 7200W amp by itself will not cost more than $1000 US to build, not including the outputs I'm likely to blow up, of course.

How much capacitance should the power supply for this have?

PassFan · 21st January 2002, 10:51 PM

Where will you find a 12000 watt transformer for 1000.00?

Kilowatt · 21st January 2002, 11:47 PM

I won't, the power supply won't have a transformer. If you read this whole thread, you'd know that. AudioFreak said that just a few posts back.

haldor · 21st January 2002, 11:50 PM

He's going to use the transformer up on the Utility pole.

I posted an explaination earlier in this thread.

Phil

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21st January 2002, 02:19 AM	#41
AudioFreak Warp Engineer On Holiday Join Date: Oct 2001 Location: Queensland, Australia	PassFan, The amp is Class B or AB so will not have much in the way of quiescent dissipation........ Also the supply is transformerless and each 900W amp will have a seperate power supply .....

21st January 2002, 02:20 AM	#42
blmn diyAudio Member Join Date: Feb 2001 Location: .	I think GRollins has made something like a watercooled amp.

21st January 2002, 07:55 AM	#43
Kilowatt diyAudio Member Join Date: Nov 2001 Location: Harlowton, MT, USA	Actually, it will have one power supply for all 8 channels. It will have a 60A breaker as an on/off switch, 4 150A discrete rectifier diodes, at least 8 200V, 31,000uF filter caps (not much for a brute like this, I know, but it will have a high PSRR, and besides, those caps are huge and expensive), smaller electrolytics, film caps, two MOVs, 20W bleeder resistors (I'd hate to see those caps discharge into a screwdriver!! There wouldn't be a srewdriver left, I'd be seeing spots and have a ringing in my ears for a week!), and possibly two big inductors mounted in a compartment under the rest of the chassis. I wonder how much tubing I'd need in the heat exchanger for this thing?

21st January 2002, 09:42 AM	#44
AudioFreak Warp Engineer On Holiday Join Date: Oct 2001 Location: Queensland, Australia	thats not gonna be anywhere big enough for this amp kilowatt.. on transients this amp is gonna load down like crazy if it doesnt have heaps and heaps of low resistance capacitance in the power supply and because all channels will peak @ the same time, the peak current draw will be in excess of 100A

21st January 2002, 10:18 AM	#45
Jeremy_Wolf diyAudio Member Join Date: Jan 2002	KiloWatt, I don't know if anyone else has asked this exactly, but what are you going to use this thing for?? Simulating earthquakes, producing 5 hz tones at 140 db? This is a serious amount of power. Of course you could just be doing it for fun which is a good enough answer for me. But if you really need that much power, wouldn't it be cheaper to buy a comercialaly made amplifier setup? I know that a crown ce2000 is rated at 975 watts/channel into 2 ohms and they only cost about 550. Get 4 of these and you have your power requirements, it will only cost 2200 dolars for all 8 channels, all of the protection circuitry is built in, all of the cooling is built in, and to top it all off, there is a warrenty and they only wieigh about 40lbs each. Not that I want to put a damper on the DIY spirit. Sometimes it is cheaper and wiser to go comercial. It's like designing a robot that can clean dishes when there are 200 dollar dishwashers for sale in every department store. But if this is a just for fun project, then good luck and take plenty of pictures for us all to see.

21st January 2002, 01:19 PM	#46
AudioFreak Warp Engineer On Holiday Join Date: Oct 2001 Location: Queensland, Australia	the problem with the above mentioned amp is that it produces 975W into 2ohms.... Kilowatt needs that kinda power into a 12ohm load.

21st January 2002, 08:56 PM	#47
Kilowatt diyAudio Member Join Date: Nov 2001 Location: Harlowton, MT, USA	Also, the 7200W amp by itself will not cost more than $1000 US to build, not including the outputs I'm likely to blow up, of course. How much capacitance should the power supply for this have?

21st January 2002, 10:51 PM	#48
PassFan diyAudio Member Join Date: Aug 2001 Location: Central FL	Where will you find a 12000 watt transformer for 1000.00?

21st January 2002, 11:47 PM	#49
Kilowatt diyAudio Member Join Date: Nov 2001 Location: Harlowton, MT, USA	I won't, the power supply won't have a transformer. If you read this whole thread, you'd know that. AudioFreak said that just a few posts back.

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21st January 2002, 11:50 PM	#50
haldor diyAudio Member Join Date: Aug 2001 Location: Columbus, Ohio	He's going to use the transformer up on the Utility pole. I posted an explaination earlier in this thread. Phil