IRFP240&IRFP9240 power amplifier schematic

[mos]

Hi, I've searched on this forum and on the internet a power amplifier(250W-300W) schematic with IRFP240/IRFP9240, and I didn't found one.Can you help me with one?
I wan't to use this amp in home but it should have the same performances with PA amp.
Please scuse-me if there are some mistake's, but my English isn't so god.
Thank's a lot, Vlad.

[Magura]

A Pass X-600 would do the job. Look at the thread in the passlabs forum named X-100 back engineered here.

Magura

[rudi]

Here is one for you. been wanting to try it for some time now. but i am sure this will heat up any room.. what I found interresting is the feedback cicuit.

regards
rudi

[carlmart]

Originally posted by rudi
Here is one for you. been wanting to try it for some time now. but i am sure this will heat up any room.. what I found interresting is the feedback cicuit.

The feedback is just using designed around a DC servo, but the chip they are using (TLO71) is not too good for that application. Something like a LF411 should do much better.



Carlos

[bigpanda]

Hi,

You like to try Anthony's AV400 ?

Give me your email and I'll sent it to you. Its too big to be posted here.

[amplifierguru]

These devices, the IRFP240/9240 have around 4-5V , Vgs on, so you will waste this much in supply voltage above Vas losses unless you operate them common source from the rails. A small source R is necessary unless you can match them very well and have good heatsinking and thermal feedback control of their operating conditions. A price to pay but, when you consider that at 250W/8ohm peak voltage is 64V and 5V extra is 300W!


I have a design which will work with cascode input stage. I just need about a week to put the finishing touches.

Cheers,
Greg

[Nelson Pass]

Originally posted by amplifierguru
These devices, the IRFP240/9240 have around 4-5V , Vgs on, so you will waste this much in supply voltage above Vas losses unless you operate them common source from the rails.

I routinely allow that much loss, as the capacitance of the Mosfet
goes to hell below about 5 volts D-S anyway.

[quasi]

I have an Elektor circuit designed for complimentary FETs. I'm at work so I'll post it tonight (8 hours).

This cct from what I recall, runs the P-channel FET on the positive rail and the N-channel on the negative rail. This means that it can run rail to rail eliminating the efficiency issues.

Anyway I'll post it tonight.

Cheers

[amplifierguru]

Yes NP,

The capacitance does indeed go a bit pear shaped - but it's still preferable to clipping prematurely, when it's going to severely distort. IMHO, it's better to have the last few volts in reserve than wasted.

That'd be a good starting point quasi, thanks.

Cheers,
Greg

[quasi]

Ok girls and boys, here is the amp I mentioned 8 hours ago (about).

It seems very nice and with the right layout and components this could be almost any power you want.

Cheers