400W amp project

[djk]

"It'll be some time before
I've got the money to buy enough parts to build a working
version with the parts you suggest," Let me know when you are ready and I'll order some.In the quantity I buy 10 pair for a stereo amp will cost less than $50.

[djss]

I'm selling Leach SuperAmp PCB's. Good design, good reputation. The boards are $25 each and they are a little bit more complicated, but the parts are not too hard to find and if you need any help I can probably manage. Check these sites to see if you are interested:

Remember, the boards are 500W into 4ohms when they are not bridged!

http://djss.hypermart.net/beast.htm
http://users.ece.gatech.edu/~mleach/superamp/

=DJSS=
(djss)(at)(mail.utexas.edu)

[Damon Hill]

djk:

I'm definitely interested in getting the MJ21193/4 transistors:
I was able to buy 10 of the -3s but they wouldn't sell the others
in less than 100s. I only got the 3s because they already
had a broken rail of that part (Active Electronics).

At this point, I'm figuring on 20 of the -4s and 10 more of the 3s;
I'll let you know in a day or several. If we can get a good price
break on a quantity order, that certainly helps. From those I
can select matched sets for my existing amp.

After that, it's finding chassis, transformers and some other
parts. Alas, I definitely don't have the money for those; I just
dropped $600 in car repairs with at least that much more in
deferred repairs, so the most I can hope to do is breadboard
a channel with a lower power transformer.

I need a job, real bad.

[Damon Hill]

Oops, let me rephrase that:

I'll need ten more of the MJ21194s and twenty of the MJ21193s.
I bought ten of the former through Active Electronics for $2.59
apiece (shipping and taxes extra).

And I've named the amplifier; it's bodacious, so it's got to be...

...Bubba.

I'm guess that 5 pairs of output devices are good for 500 watts
into 8 ohms and I might get away with 1000 watts into 4 ohms,
but I'm not counting on it surviving 2 ohm loads without some
serious protection circuitry. I'm thinking more in terms of
swinging a lot of voltage rather than a lot of current.

[JBL]

On that subject with anything higher than 300 watt
mosfet is better. bjt are somewhat to fragile for high power. If you use high power mosfet it's going to be nearly indestructible.

It's said that Mosfet got high distortion but at high power rating this does not really bother.

[AudioFreak]

Originally posted by JBL
On that subject with anything higher than 300 watt
mosfet is better. bjt are somewhat to fragile for high power. If you use high power mosfet it's going to be nearly indestructible.

It's said that Mosfet got high distortion but at high power rating this does not really bother.

Yeah it'll mean higher distortion and mosfet mist unless it is highly biased but @ >300W i dont think your primary concern is absolute hifi quality.

[djk]

"On that subject with anything higher than 300 watt
mosfet is better. bjt are somewhat to fragile for high power. If you use high power mosfet it's going to be nearly indestructible. " A statement that is often made, and never with any proof.The most commonly used MOSFET for this use is the 2SJ162/2SK1058 pair.About USD$7 each.Only 100W SOA at 100V and a maximum die temperature of 150*C.Consider the MJ21193/21194 pair.About USD$2.50 each.Has 200W safe area at 100V and a maximum die temperaure of 200*C.The same amount of money will buy you over FIVE times as much safe area of operation wattage.Of course if you like the sound of lateral MOSFET bass(can you say mud?).Of course the mud is from the 12V drain to source voltage drop at 7A, that means it is like a 1.7 ohm resistor.The bipolar is less than 1.4V at 8A, or .17 ohm, ONE TENTH the loss.

[hugobross]

Kilowatt,

I've got a very nice schematic for you, but it's too big to let it appear in this thread. Look at the link in my new thread.


Best regards,

hugobross.