Okay so my first attempt at a solid state amp, justneed some help basically. The thing that got me into the idea was the 'Best amp that I've very heard' thread. Looking to build something similir but i don't have that budget! So I came up with the rquirements of this amp:
Needs to be dual channel
100Wrms per channel to 8ohm (but want to be able to drive 4ohm too)
For the cooling and the case design of the amplifier I'm want to use TO-220 package style MOSFETs.
I want a active two channel low pass filter output for a sub.
Realistic budget of £200 just for the electronics not chassis or connectors.
I don't want anything like balance, bass control ect. just a simple power amp!
Looking at space I want to stick to the size of a 2u rack case.
If someone could point me in the direction of some schematics and pcb layouts if possible it would be great help!
I have most probably forgot something if someone could point be where would be good!
Thanks
Boscoe
Needs to be dual channel
100Wrms per channel to 8ohm (but want to be able to drive 4ohm too)
For the cooling and the case design of the amplifier I'm want to use TO-220 package style MOSFETs.
I want a active two channel low pass filter output for a sub.
Realistic budget of £200 just for the electronics not chassis or connectors.
I don't want anything like balance, bass control ect. just a simple power amp!
Looking at space I want to stick to the size of a 2u rack case.
If someone could point me in the direction of some schematics and pcb layouts if possible it would be great help!
I have most probably forgot something if someone could point be where would be good!
Thanks
Boscoe
Member
Joined 2009
Paid Member
That doesn't have TO-220 output devices.
For the sub out unfortunately it's a little more complex than first glance, take a look at the sub-woofer controller project on my website.
Also I have a TO-220 MOSFET amp that I designed somewhere and it worked really nice, I can dig out the schematic and PCB design if you want.
For the sub out unfortunately it's a little more complex than first glance, take a look at the sub-woofer controller project on my website.
Also I have a TO-220 MOSFET amp that I designed somewhere and it worked really nice, I can dig out the schematic and PCB design if you want.
I found all the stuff out, I remember now I was going to do some tweaking to the layout to improve ease of build. I'll try and get that done over the next few days. I can also put a kit together if you are stuck for the bits.
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Hi,
100W into 8r0 would be equivalent to 200W into 4r0.
That would need between 600W and 800W of FET output devices.
2pair of irfp240/9240 (To247)would just about do it. 3pair of other 120W to 150W To220 FETs would be a sensible starting point.
You would struggle to get 40Vpk (100W into 8r0) at the output of a FET source follower amplifier from a 35+35Vac transformer, so you would probably use a 40+40Vac transformer. You would need ~400VA to 800VA to meet the 200+200W target.
100W into 8r0 would be equivalent to 200W into 4r0.
That would need between 600W and 800W of FET output devices.
2pair of irfp240/9240 (To247)would just about do it. 3pair of other 120W to 150W To220 FETs would be a sensible starting point.
You would struggle to get 40Vpk (100W into 8r0) at the output of a FET source follower amplifier from a 35+35Vac transformer, so you would probably use a 40+40Vac transformer. You would need ~400VA to 800VA to meet the 200+200W target.
Quasi's NMOS200 amp would fit the bill I think. IS there any particular reason to use TO-220 mosfets and not TO-247 ? Anyway, he accommodates both with his extremely neat design 
Nmos200 - Quasi's DIY Audio Site
Nmos200 - Quasi's DIY Audio Site
It is capable of over 100W easily, I went for 150W. You should choose the rail voltage depending on your speaker impedance.
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