Holton separate power supply for imp/output!

B.I.G · 15th February 2005, 04:41 PM

i would like to use separate powersupplys for the imput and output of the amplifier .... the imput pws should be about 5v higher than the output. i heard this could make the amp more eficient! is that true ? why is that ?

B.I.G · 15th February 2005, 04:43 PM

oh i forgot it`s for Holton`s 400W symetrical amp http://www.aussieamplifiers.com/down...ed%20AV400.pdf

Mr Evil · 15th February 2005, 04:52 PM

It is true. It's because MOSFETs need a certain voltage between gate and source to turn fully on. If the driver stage has the same voltage rails as the output stage then the gates can only ever be taken up to rail voltage at most. This means that the sources (and thus the output) will only be able to reach Vgs less than the rails.

With higher rails for the driver stage then the gates can be taken above the output stage rails and thus the sources can reach very close to the (output stage) rails, effectively increasing efficiency.

Be careful not to drive the gate too much higher than the source though, since it will damage the MOSFET.

B.I.G · 15th February 2005, 05:08 PM

woow quick reply ! ! wahat you are saying makes a lot of sense ... about to high VGS the amp already has a zenner between gate and source

15th February 2005, 04:41 PM	#1
B.I.G diyAudio Member Join Date: Mar 2004 Location: Home	Holton separate power supply for imp/output! i would like to use separate powersupplys for the imput and output of the amplifier .... the imput pws should be about 5v higher than the output. i heard this could make the amp more eficient! is that true ? why is that ? __________________ B.I.G

15th February 2005, 04:43 PM	#2
B.I.G diyAudio Member Join Date: Mar 2004 Location: Home	oh i forgot it`s for Holton`s 400W symetrical amp http://www.aussieamplifiers.com/down...ed%20AV400.pdf __________________ B.I.G

15th February 2005, 04:52 PM	#3
Mr Evil diyAudio Member Join Date: Aug 2004 Location: Behind you	It is true. It's because MOSFETs need a certain voltage between gate and source to turn fully on. If the driver stage has the same voltage rails as the output stage then the gates can only ever be taken up to rail voltage at most. This means that the sources (and thus the output) will only be able to reach Vgs less than the rails. With higher rails for the driver stage then the gates can be taken above the output stage rails and thus the sources can reach very close to the (output stage) rails, effectively increasing efficiency. Be careful not to drive the gate too much higher than the source though, since it will damage the MOSFET. __________________ http://mrevil.pwp.blueyonder.co.uk/

15th February 2005, 05:08 PM	#4
B.I.G diyAudio Member Join Date: Mar 2004 Location: Home	woow quick reply ! ! wahat you are saying makes a lot of sense ... about to high VGS the amp already has a zenner between gate and source __________________ B.I.G

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