Biggest amp

[skyraider]

What is the biggest gainclone anyone here has built based on 3875/3886?
Anyone ever went beyond 200 watts? I am planning something for a subwoofer. Kinda looking for 800 watts.

[phase_accurate]

800 Watts approx into 4 Ohms should be feasible, given that U:

-use enough of them in parallel and bridged
-have sufficient cooling
-use a stiff enough PSU

80 Volts peak would give 800 Watts into 4 Ohms. Since you can't go much over 40 Volts supply voltage the last statement would be important.

Why don't you just use a conventional (i.e. discrete) power amp ?

Regards

Charles

[skyraider]

I always f#@k up with discretes. Furthermore, its hard to get the parts needed, treasure hunting is difficult in malaysia. I just want to try to make a monster out of 3886s.
Anyone did it up to 400 watts then?

[carlosfm]

You can parallel several LM3886s.
Then, bridge.
Even then, I can't see how you could get much more than around 200 watts/8 ohms, double that at 4 ohms (with a big PSU).
If all this thing will sound good, that's another story.

[psychosteve]

better off looking at lm4780 or stk4231v. i know the stk will take up to +75v -75v, (for power of 100 watts with +-50v) its gota be worth a look, plus i personly like the package/pin shape. there are a few higher rated ones in the range, but i cant remember the numbers. there are some triple amp chips as well so parallel three amp then bridge to three more in two packages. its gota be good for getting past 500watts into 4ohms.
or just buy a solid state kit, something like a zeta, or one of the kits from E.S.P. rod elliot does some great stuff at not much money. see you soon, steve.. ..

[skyraider]

stk was my first diy, at that time, what do I know about heatsinks? Got it singing for about 5 minutes and thats it
Rod elliot has something for 500 watts. If can I wanted to push it more.. Im considering using LM3875 to drive additional mosfets or power transistors, since it is already a good sounding chip.

I cant remember who made those stks..

[joensd]

I always f#@k up with discretes. Furthermore, its hard to get the parts needed, treasure hunting is difficult in malaysia. I just want to try to make a monster out of 3886s.

At these power levels I doubt you´ll have it easier with IC amplifiers than with discretes.
As already mentioned you can go easily up to 200W with the proper circuit from the BP-application note from National Semiconductor and a nice PCB.
For anything more I´d rather build something like Anthony Holton´s mosfet-amplifiers or the optimos from Randy Slone.
or Rod Elliot´s amp. You can get PCB´s for all of these.
Looking at the prices of the LM38XX´s you´ll be probably cheaper off as well.

[skyraider]

anyone tried one of those class-D amplifiers from NSC?
I found one that goes 170watts, but I cant remember the exact number.
And I guess it is easier to build than parallel/bridged 3886. Still it is too low..

[joensd]

class-D amplifiers

Completely forgot about those.
What about the new hypex-modules?
http://www.hypex.nl

[skyraider]

jens,
whats wrong with class-D subwoofers?
I believe Hypex models are all class-D. UcD400 sounds interesting too..400watts into 4 ohms.