to-3 transistor on aleph-x

tze-hao yen · 13th February 2005, 02:23 AM

hi every body is there any posible to use a more powerfull to-3 metal caze trasistor for the aleph-x so we don't have to martch so many pair s of FET to get hi power aleph-X

kilowattski · 13th February 2005, 10:38 AM

Sure, if you can find TO-3 case HEXFETS with acceptable electrical specifications there is no reason not to use them.

Nelson Pass · 13th February 2005, 06:40 PM

An IRF250 is a lot like 2 IRF240's in a case, but less than
twice the dissipation capacity.

tze-hao yen · 14th February 2005, 12:15 AM

hi but if i am using 3X4 mosfet currently how can i adjust the bais? right now i think i am have an 12 amp Ip so what i am looking now is that going to be like 16 amp if i put 8 irf-250?(2x4)

GRollins · 14th February 2005, 12:38 AM

Working out the bias with TO-3 devices will be exactly the same process as with any other case. Start by determining your load and target wattage. Determine how much voltage and current you will need to achieve that wattage. Then use enough devices to spread the heat around so that you aren't burning up output MOSFETs. There's no magic number of output devices. Feel free to add as many or as few as you need for your system. Just be aware that if you start building a really hairy amp, say 600-800W or so, the front end will begin to run out of steam. Since most people would have trouble living with the roughly 4kW of heat that such a pair would generate at idle, I don't think we'll see too many amps of that size built.

Grey

tze-hao yen · 14th February 2005, 02:24 AM

i only want about 150 watt 4 ohm ? what will be the voltage and current?

tze-hao yen · 14th February 2005, 02:39 AM

so 150watt 4 ohm will be like 34.6volt and 8.6Amp?is that +and - supply voltage and 8.6 is the current you going to read from the amp meter right?

kilowattski · 14th February 2005, 11:29 AM

Download the AXE 1.2 spreadsheet and plug in the numbers. The spreadsheet will do the calculations for you.

Leolabs · 15th February 2005, 10:54 AM

Does Japanese MOSFET suitable for this project????

13th February 2005, 02:23 AM	#1
tze-hao yen diyAudio Member Join Date: Jul 2004 Location: brooklyn	to-3 transistor on aleph-x hi every body is there any posible to use a more powerfull to-3 metal caze trasistor for the aleph-x so we don't have to martch so many pair s of FET to get hi power aleph-X

13th February 2005, 10:38 AM	#2
kilowattski diyAudio Member Join Date: Aug 2003 Location: Long Island, New York	Sure, if you can find TO-3 case HEXFETS with acceptable electrical specifications there is no reason not to use them. __________________ ----------------------------------------------- Kilowattski

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13th February 2005, 06:40 PM	#3
Nelson Pass The one and only Join Date: Mar 2001	An IRF250 is a lot like 2 IRF240's in a case, but less than twice the dissipation capacity.

14th February 2005, 12:15 AM	#4
tze-hao yen diyAudio Member Join Date: Jul 2004 Location: brooklyn	hi but if i am using 3X4 mosfet currently how can i adjust the bais? right now i think i am have an 12 amp Ip so what i am looking now is that going to be like 16 amp if i put 8 irf-250?(2x4)

14th February 2005, 12:38 AM	#5
GRollins diyAudio Member Join Date: Feb 2001 Location: Columbia, SC	Working out the bias with TO-3 devices will be exactly the same process as with any other case. Start by determining your load and target wattage. Determine how much voltage and current you will need to achieve that wattage. Then use enough devices to spread the heat around so that you aren't burning up output MOSFETs. There's no magic number of output devices. Feel free to add as many or as few as you need for your system. Just be aware that if you start building a really hairy amp, say 600-800W or so, the front end will begin to run out of steam. Since most people would have trouble living with the roughly 4kW of heat that such a pair would generate at idle, I don't think we'll see too many amps of that size built. Grey

14th February 2005, 02:24 AM	#6
tze-hao yen diyAudio Member Join Date: Jul 2004 Location: brooklyn	i only want about 150 watt 4 ohm ? what will be the voltage and current?

14th February 2005, 02:39 AM	#7
tze-hao yen diyAudio Member Join Date: Jul 2004 Location: brooklyn	so 150watt 4 ohm will be like 34.6volt and 8.6Amp?is that +and - supply voltage and 8.6 is the current you going to read from the amp meter right?

15th February 2005, 10:54 AM	#9
Leolabs diyAudio Member Join Date: Dec 2004 Location: Bukit Mertajam	Does Japanese MOSFET suitable for this project????

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