Looking for 100wpc 8ohm mosfet based PCB

Dougie085 · 1st July 2007, 11:09 PM

I'm looking for a nice Class A mosfet based amp that will do 100wpc at 8ohms. I'd like it to be a PCB that is available somewhere that I can buy right now. Any idea's? Right now the speakers are Klipsch Reference but eventually it will be large 3 ways using RS driver most likely.

AndrewT · 1st July 2007, 11:20 PM

Hi,
The chances of finding a 100W ClassA PCB is near nil.

jacco vermeulen · 1st July 2007, 11:20 PM

If you really don't know: the A75 design by Mr Pass and Mr Thagard.
You can download the two parts of the A75 building manual from Mr P., order the A75 main board from AudioXpress.

Dougie085 · 1st July 2007, 11:25 PM

Well 60 wpc at 8ohms would be enough. And over 100 at 4ohms would be nice.

Dougie085 · 2nd July 2007, 04:27 AM

Is there a BOM for the Aleph 5 somewhere? I've searched and can't find it. I'm thinking of ordering the boards from chipamp.com and building a pair of Aleph 5's.

AndrewT · 2nd July 2007, 07:33 AM

Hi,
ClassA output power is limited by the level of ClassA current available.

If you have a 60W into 8ohm ClassA output and instead connect a 4ohm load the maximum ClassA output drops to 30W.
Use P=I^2*Rload instead of the usual P=V^2/Rload to see the effect of a load change.

djk · 2nd July 2007, 01:24 PM

http://www.ska-audio.com/diy/003.html

GB300D (mono)

Bare PCB US$60 + $4 p&p

Full module kit US$135 + $8 p&p

Built/tested module US$200 + $12 p&p

jacco vermeulen · 2nd July 2007, 02:25 PM

Good one, Dennis.

Dougie,
you can still use IRFP9140s for the full Class A version of the GB300D.
No idea how the Class A version of the 300 sounds, i haven't read of someone constructing one yet, the GB150D in 50 watt A i assembled is excellent value for money and really fast to put together.
Ordering the IRFP9140 is apac on your end.

1st July 2007, 11:09 PM	#1
Dougie085 diyAudio Member Join Date: Nov 2005 Location: Ohio	Looking for 100wpc 8ohm mosfet based PCB I'm looking for a nice Class A mosfet based amp that will do 100wpc at 8ohms. I'd like it to be a PCB that is available somewhere that I can buy right now. Any idea's? Right now the speakers are Klipsch Reference but eventually it will be large 3 ways using RS driver most likely.

1st July 2007, 11:20 PM	#2
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	Hi, The chances of finding a 100W ClassA PCB is near nil. __________________ regards Andrew T.

1st July 2007, 11:20 PM	#3
jacco vermeulen diyAudio Member Join Date: Oct 2004 Location: At the sea front, just under Rotterdam	If you really don't know: the A75 design by Mr Pass and Mr Thagard. You can download the two parts of the A75 building manual from Mr P., order the A75 main board from AudioXpress. __________________ Looks like Sponge Bob has killed another thread.

2nd July 2007, 07:33 AM	#6
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	Hi, ClassA output power is limited by the level of ClassA current available. If you have a 60W into 8ohm ClassA output and instead connect a 4ohm load the maximum ClassA output drops to 30W. Use P=I^2*Rload instead of the usual P=V^2/Rload to see the effect of a load change. __________________ regards Andrew T.

2nd July 2007, 01:24 PM	#7
djk diyAudio Member Join Date: Feb 2001 Location: USA	http://www.ska-audio.com/diy/003.html GB300D (mono) Bare PCB US$60 + $4 p&p Full module kit US$135 + $8 p&p Built/tested module US$200 + $12 p&p __________________ Candidates for the Darwin Award should not read this author.


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1st July 2007, 11:25 PM	#4
Dougie085 diyAudio Member Join Date: Nov 2005 Location: Ohio	Well 60 wpc at 8ohms would be enough. And over 100 at 4ohms would be nice.

2nd July 2007, 04:27 AM	#5
Dougie085 diyAudio Member Join Date: Nov 2005 Location: Ohio	Is there a BOM for the Aleph 5 somewhere? I've searched and can't find it. I'm thinking of ordering the boards from chipamp.com and building a pair of Aleph 5's.

2nd July 2007, 02:25 PM	#8
jacco vermeulen diyAudio Member Join Date: Oct 2004 Location: At the sea front, just under Rotterdam	Good one, Dennis. Dougie, you can still use IRFP9140s for the full Class A version of the GB300D. No idea how the Class A version of the 300 sounds, i haven't read of someone constructing one yet, the GB150D in 50 watt A i assembled is excellent value for money and really fast to put together. Ordering the IRFP9140 is apac on your end. __________________ Looks like Sponge Bob has killed another thread.

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