MOSFET Amplifier IRFP240/IRFP9240

[VIPINSAINI20]

My contribution for this amplifier.

Can you share your Assembled boards pictures and your experience with this amplifier,
And
Please share any information related with building this one

 

[nigelwright7557]

Here is my old design for 240/9240 output amp.
It uses the 1980's Maplin lateral mosfet circuit updated to use 240/9240 mosfets.

 

[steveu]

Here is my old design for 240/9240 output amp.
It uses the 1980's Maplin lateral mosfet circuit updated to use 240/9240 mosfets.
View attachment 1074719

That's almost the same as the LTC spice example "100W.asc"

 

[nigelwright7557]

Maplin used the example circuit in the lateral mosfet datasheet.
It wasnt perfect as some amps oscillated a bit.
The small pf caps were a little too small for good stability.
I increased the size of them slightly for my circuit.

 

[alain98]

9240 and 240

are not complementary, look at the curves.

These are switching devices and its properties are not suitable for linear amplification

You only have to use N Channel Switching Mosfets. Build the same amplifier with just N-Channel IRFP240 and you will hear the difference

Then you will throw the 9240/240 Mosfet amp in the bin

Hello NMOS,
If we change IRFP924O for IRFP240 in this amp, do we have to make others change on the schematic?
Thanks in advance for your reply.

 

[Zen Mod]

differentiate N vs. P polarity

 

[steveu]

Hello NMOS,
If we change IRFP924O for IRFP240 in this amp, do we have to make others change on the schematic?
Thanks in advance for your reply.

Obviously, yes. It's like the expression "two left feet". Two N channel devices like two NPN is (usually) called Quasi complimentary, where the negative output comes from a CFP aka Sziklai, that use a PNP or P-channel driver. There is also the Circlotron topology (and similar) which are completely different and requires several independent floating power supplies, per channel hence not popular. Matching output devices can cancel even harmonic distortion, but that is contrary to phyco-acoustics that favors even harmonics. Instrument amplifiers deliberately create even harmonic distortion to improve the musicality of the instrument. This works because instrument amplifiers do not mix the sound of different sources. There is a You-tube video about Pass amplifiers where they recommend setting a bias offset to favor even harmonic distortion rather than the minimum distortion. Poorly matched complimentary devices may outperform Quasi designs because the speed and phase response are critical to stable feedback. Exicon makes Lateral MOSFETs especially for linear amplifiers and apparently the results are spectacular, but I can't speak from experience. The results using the IR devices can be very good, so cost and availability may be the deciding factor.

 

[audio25]

,

122

 

[prasi]

MOS200 II

MOS200B

whats the difference between these two and which version is working amp?

 

[cook77]

Can I use this diagram for +/-56V to get +/-15V for preamp?

Use this PSU circuit...

S

 

[taghy]

Hello. Does the 2016 Titan hv23 amplifier have a PCB?

 

[vargasmongo3435]

I do have it but is just an idea that I had a few years ago I never tested I was just doing more layout practice those years

 

[stocktrader200]

I use a zener with irfp240 irfp9140 works just fine. Still is ok when over biased to 7.5v
5.6 works great.

 

[meanman1964]

How much power ( Watts ) would this version have with 75 Vdc rail voltage by 8 Ohm ?

 

[adason]

Did you read the first post?

 

[meanman1964]

I was hoping to get more output power by adding more power fets .

 

[adason]

I use less than one watt at normal listening level.
You can not add more outputs unless you beef up drivers. Possible, go for it.
Or get behringer or lab gruppen.

 

[meanman1964]

Adamson , did you build the HV23 ?
I need a extra power amp to drive my OB speakers.

 

[adason]

Who's adamson?

 

[meanman1964]

I mean you adason , just a typo