High power subwoofer amplifier

[Tekko]

Heres a sketch for a high power subamp i plan to build just for fun:
http://i.imgur.com/WMYI3.png

[ingenieus]

Looks good, but the part numbers on the circuit are hard to read. Could you give us a large version?

The placing of the compensation caps around the pre-drivers is not something that is seen everyday, but if it works then it works.

[Tekko]

Without them i had a small sub millivolt oscillation in the simulation.

Heres a larger version of the schematic, the output transistors are MJW21195 and MJW21196 but i don't have simulation models for these yet.

http://i.imgur.com/xJHfp.png

[Bensen]

Be carfull with the power simulation.
You have to devide the power by 2.828 (2x 1.414) if you want to have the rms power, LTspice is using maximum voltages and maximum currents.

[Tekko]

Yes i know and my power supply is rated at 500VA so 300W RMS is the max practical output power if even that.

[Nico Ras]

Originally Posted by Bensen

Be carfull with the power simulation.
You have to devide the power by 2.828 (2x 1.414) if you want to have the rms power, LTspice is using maximum voltages and maximum currents.

Why 2.828. it is simply 2;

√2 x √2 = 2 not 2.828

[Nico Ras]

This amp will clip due to your transformer running out of gas. If you had an +800VA you would be looking more at 560 watt "rms" into 4 Ω resistive load.

[Bensen]

Originally Posted by Nico Ras

Why 2.828. it is simply 2;

√2 x √2 = 2 not 2.828

Indeed, you're right!

[Tekko]

Atleast it clips before the SOA of the outputs is exceeded. And i will never ever reach anywhere near clipping anyways, any of my amps are lucky to make it past 5 watts as i live in a apartment.

I don't use a sub in my system so this build is only for fun, just like all my other projects.

[Nico Ras]

You are well inside the SOA.