Aleph 5 (4 x IRFP240 per channel)

peter7 · 21st May 2008, 05:37 PM

Hello, I want to build Aleph 5 have 4 x IRFP240 per 1 channel (original is 6 x IRFP240), is it possible? is it need to change some?

Stones · 22nd May 2008, 01:59 AM

ok you have had 61 reads and no response, this happens when you ask a question that a little searching will answer.

The original Aleph 5 had 6 fets, if you lower this to 4 with no other changes you will have one third less current available.
You can find an excel sheet done by wuffwaff that will help you calculate the effects.

I don't feel like you know what voltage or current you need so I can't concisely help you.

peter7 · 22nd May 2008, 05:29 PM

Hello Stones, thanks for your reply, I use +- 35VDC which is original circuit ,some people told me just change the R64-66 & R40-42 from 1 ohm to 0.7 ohm for 4 fets ,is it correct??

Stones · 23rd May 2008, 12:01 AM

There are other ways to change the current but it sounds about right, you know the fets will run hotter than god intended in the original design. Would it not be better to build it with lower rails (Aleph 3, or better yet build the AlephJ) what load are you running into?

karajak · 26th May 2008, 06:32 PM

hi ! i want to use 8 240s instead of 6 for aleph5 with 31,5 V. The use of 1,5ohm resistors is the action correct?

Blues · 26th May 2008, 06:54 PM

With lower supply voltages and more output devices you can keep 1R power resistors for a better performance in low impedance loads. 2A total bias.

karajak · 26th May 2008, 07:30 PM

thanks for the reply.i will keep the 1om resistors.i wonder if this way the temperature per fet is lower?

21st May 2008, 05:37 PM	#1
peter7 diyAudio Member Join Date: Apr 2005 Location: hong kong	Aleph 5 (4 x IRFP240 per channel) Hello, I want to build Aleph 5 have 4 x IRFP240 per 1 channel (original is 6 x IRFP240), is it possible? is it need to change some?

26th May 2008, 06:54 PM	#6
Blues Lightning In A Bottle diyAudio Member Join Date: Sep 2003 Location: The Milky Way	With lower supply voltages and more output devices you can keep 1R power resistors for a better performance in low impedance loads. 2A total bias. __________________ Leap into the Warpspeed wormhole... http://www.6moons.com/audioreviews/warpspeed/1.html

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22nd May 2008, 01:59 AM	#2
Stones diyAudio Member Join Date: Jan 2004 Location: MN	ok you have had 61 reads and no response, this happens when you ask a question that a little searching will answer. The original Aleph 5 had 6 fets, if you lower this to 4 with no other changes you will have one third less current available. You can find an excel sheet done by wuffwaff that will help you calculate the effects. I don't feel like you know what voltage or current you need so I can't concisely help you.

22nd May 2008, 05:29 PM	#3
peter7 diyAudio Member Join Date: Apr 2005 Location: hong kong	Hello Stones, thanks for your reply, I use +- 35VDC which is original circuit ,some people told me just change the R64-66 & R40-42 from 1 ohm to 0.7 ohm for 4 fets ,is it correct??

23rd May 2008, 12:01 AM	#4
Stones diyAudio Member Join Date: Jan 2004 Location: MN	There are other ways to change the current but it sounds about right, you know the fets will run hotter than god intended in the original design. Would it not be better to build it with lower rails (Aleph 3, or better yet build the AlephJ) what load are you running into?

26th May 2008, 06:32 PM	#5
karajak diyAudio Member Join Date: Jan 2008 Location: ATHENS	hi ! i want to use 8 240s instead of 6 for aleph5 with 31,5 V. The use of 1,5ohm resistors is the action correct?

26th May 2008, 07:30 PM	#7
karajak diyAudio Member Join Date: Jan 2008 Location: ATHENS	thanks for the reply.i will keep the 1om resistors.i wonder if this way the temperature per fet is lower?