DW300 project - one HiFI Audio Amplifier that can run stable on 2 ohm

Thread Starter


Joined Nov 14, 2008
Hello everyone,

DW300 project - which I want to develop it with power supply diagram and other electronic circuits considered relevant - derived from an electronic scheme published by user @wahab on diyaudio.com. Initials DW come from Donpetru Wahab.

In fact, in my version, I presented IRFP240/9240 transistors and added the protection and soft start. After that I changed some values ​​of electronic components to bring them in the optimum functioning of the amplifier. Finally, I designed a PCB that meet the most stringent design rules.

I hope your's enjoy this project that I'm thinking of turning it into a much more laborious project which include: a power supply, input circuits and/or audio preamplifier (schematic and printed circuit). In this respect I'd really like to read some recommendations or opinions.

If you plan to use lateral MOSFET transistors, such as ALF16N20W / ALF16P20W, it is enough to make the following changes:
- replace with a jumpers these electronic components: D101 and R21;
- remove from the circuit components R22 and R23;
- connected in series with the emitter of the transistor Q13 one adjustable potentiometer: 100 or 250 ohms.

!!!! If you think use lateral MOSFET transistors, such as those exemplified above, then I recommend you do not use the amplifier on less than 3 ohms impedance. Do not forget that.

The project presented is a simple prototype, so, depending on the characteristics of bipolar transistors used might to need small adjustments (for example, changing the value of resistor from the bias circuit). This will set in the stage for achieving practical circuit. We can fix these issues - if applicable, remains to be seen - with continued discussion of this topic.

In the second PDF file listed below have submitted plans for achieving copper top and bottom in D.I.Y. regime of the audio amplifier.
The amplifier can be built and in a single layer, replacing the TOP layer with jumpers. In this case, supply routes sits solder.

I think, if anyone wants, to realize some PCB's after pass the practical test of the prototype.


So, the project I would like to extend it will bring them and other useful circuits.

Dw300 project is an audio amplifier with multiple applications, from wide band audio applications and going to the subwoofer's. If you are thinking of looking for a reliable subwoofer amplifier, it is not bad to realize DW300. So, DW300 is an ideal project for subwoofer and not only that. Audio amplifier can charge 300Wrms into 2 ohms OR 150 ... 170W into 4 ohms with THD less than 0.01% (typic 0.007%).

Finally, I would like to read some opinions, a kind of first review, for this project, which can turn into something quite promising. That depends on your's.


Last edited by a moderator: