400W amp project

Does anyone know where I can find a PCB layout for the 400W amp here? Has anyone built it or know anything about it?

http://members.tripod.com/valveaudio/schematics.htm

(for those concerned, it has nothing to do with the 7200W project. I'm just building this because I have subs for it, and for something to do. It's a lot more sane, and I'll be building it exacly to specs.)

[Edited by Kilowatt on 12-08-2001 at 01:33 AM]
 
I just figured it would be faster and cheaper (not easier though) to etch one than have it shipped from Indonesia. You know it will cost more than $5.00, and I need two of them. I might buy them anyway though if I can't find a layout.

Anyway, I don't see anything too strange in that schematic. Just some resistors, capacitors, diodes, transistors, an one inductor (is that even necessary?, and it's not on the parts list). I can get everything, I've checked.
 

djk

R.I.P
2001-02-04 4:23 am
USA
Just order the board from the author.His price is very reasonable.Don't expect this design to put out 400W unless your supply is very stiff.Expect the drivers to blow up.They are only rated for +/- 50V.Better yet use MJE15030/15031 for drivers and MJ15022/15023 for the outputs.I'm not sure about the BC numbers.Check and see that they are rated for at least 80V or use MPS8099/8599.C18 should be at least a 250V rated part.C15 and C17 should have something around 22µF in parallel with them.The outputs should have flyback diodes across them.Remember either the bias diode string or the bias transistor must track the temperaure of the output stage.
 

djk

R.I.P
2001-02-04 4:23 am
USA
This is a pretty straight forward adaptation of a Leach.The MPS8099/8599 are recommended by Leach and will go up to +/- 75V, beyond that you should probably go with 2N5401/5551 which is what Hafler used in this circuit in the DH500.The B649/D669 are OK up to +/- 85V.
 
People generally like tubes because they add second-harmonic distortion and produce a "warmer" sound.

I think a lot of the stigma surrounding MOSFETs came from when there was only relatively bad mosfet technology, it was used in badly designed mid-fi gear and as a result didn't sound very good.

Modern MOSFETs as well as modern designs incorporating them are very good.

They're also not necessarily more expensive, but even so, we're not talking a huge total cost difference here.

Static sensitive? Just don't be stupid and its not a problem.

Both have pros and cons but for this particular application there seems really to be no reason to dislike a design because it uses MOSFETs.

That having been said, if you just want to use BJTs, sure, go ahead! Just try not to close out some possible good options because of it.