113 Watts at 8Ω Op-amp input MOSFET Power Amplifier Project

Project 62 utilizes an op-amp in the front-end input stage with ZTX753/ZTX653 BJT drivers coupled to the paralleled-complementary IRF640/IRF9640 power MOSFETs.
Project 62 is based on an article written by Reinhard Metz, published in the April 1992 issue of Radio Electronics magazine, who kindly gave permission to use his article as a reference. Even though the project is more than 30 years old, the output stage is a remarkable and innovative design that deserves attention.
The power output of the amplifier is about 113 watts at 8 Ω with ±45 VDC power supply rails. The power output rating was acquired by measuring the voltage across the 8Ω dummy load when a 1KHz 0.495Vrms sine wave signal is applied to the input of the amplifier.
An 8-pin IC socket was intentionally populated in the prototype so that other types of op-amps (OPA604, TLE2071, TL071, and TL081) could be evaluated.
Overall, granting that the audio power amplifier design was developed more than 30 years ago to date, the revisited project did not disappoint but rather resulted in an exciting build after all!

[@stevesmyth4982]

Interesting that there are no low value (

[@buildaudioamps]

Thanks for your comment. Please read buildaudioamps.com/project-5-mosfet/ I have built the prototype of this project in 6/12/2014. I'll try to revisit this project using an Exicon ECX10P20/ECX10N20.

[@jamesadvincula477]

bro I hope you publish your work or make a pdf copy on it

[@bazrazin1]

how do mosfet o/p stage work, i had built 3055 & 2955 complementary push pull stage, a mosfet is not a linear device like a BJT.

[@buildaudioamps]

You can read all about it here: buildaudioamps.com/project-52/ and view about it here: kzbin.info/www/bejne/e3m3lYGOmclpgK8

[@ncuzdvarga4918]

Where to find schematic and pcb for the project? Thank's

[@buildaudioamps]

Send a request to [e-mail]

[@nearchd504]

Is there any benefits of mosfets in output stage over transistors?

[@buildaudioamps]

You can read all about it here: buildaudioamps.com/project-52/ and view about it here: kzbin.info/www/bejne/e3m3lYGOmclpgK8

[@nearchd504]

@@buildaudioamps thanks, I will read it

[@AaSound97]

good

[@smurali60]

super

[@iceberg789]

built any germanium amp ?

[@buildaudioamps]

Thanks for asking. Yes, my first transistor amp build was an all-germanium transistor. An OC71/2SB175 input tone control preamp connected to a 2SB178 driving an input phase splitter transformer then 2x AD149 or 2SB449 TO3 power output transistors driving the 10-watt output transformer. Thermal runaway was its problem. It was fun, then came the silicon 2N3055/2N2955.

[@iceberg789]

@@buildaudioamps interesting. if you still have that, pls post a video.

[@buildaudioamps]

I apologize and hope you'll understand that the amplifier project you are asking about is no longer relevant and has no value for dissemination. To date it is an outdated technology, IMO, and will not meet the current quality and performance in comparison to the easily available and affordable silicon transistors.

[@iceberg789]

@@buildaudioamps right. but still has some value among retro enthusiast community & guitar amp users.

[@smurali60]

BOM please

[@buildaudioamps]

It's always available by request at [e-mail]