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

[donpetru]

Hello everyone,

It was a long awaited thread who was born from the next thread:
All Hitachi Lateral Fet amplifier for DIY described by Paul Kemble

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 thread mentioned above. 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.

Gerber files of the project below can make available to any user after a modest donation (minimum 20 USD) to my website. Donation can be made by accessing donation button on my website: www.tehnium-azi.ro
After making a donation, you will receive an e-mail Gerber files.

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.

[Mdhara Stavo]

Is this a working amplifier or is it still under test? Would like to try it

[donpetru]

It's just a prototype that any others should be tested. Who want to test it? May work at first, without any changes, or you could even take some practical adjustments.

[dadod]

Originally Posted by donpetru

Finally, I designed a PCB that meet the most stringent design rules.

I would not say so, you should look the threads with discution over PCB layout roles.

[donpetru]

@dadod, let's not say that because I made a pretty good PCB, especially in a short time. Of course you can modify the PCB but it makes no sense, because it's not worth to change something that works.

Anyway, thanks for the reply.

[Samuel Jayaraj]

donpetru, thanks a ton for your contribution to diyaudio. Is this 300 watts into 8 or 4 ohms?

[wintermute]

Hi Donpetru. I have an amp based on the Hitachi application notes. The designers of that amp's PCB at the time said that the layout was absolutely critical, with small changes making big differences (always in a bad way) in performance.

I would certainly say that you may have to try a number of iterations of the layout before you get something that performs acceptably. Of course you may be lucky and get it first go.

Tony.

[donpetru]

@Samuel Jayaraj read this:

Originally Posted by donpetru

Hello everyone,
Audio amplifier can charge 300Wrms into 2 ohms OR 150 ... 170W into 4 ohms with THD less than 0.01% (typic 0.007%).

LATER EDIT: I addition to the quoted words. Input amplifier needs to reach the power output of the above quotation about 0.55Vrms.
Of course, the amplifier can reach 400W/2Ohmi but with distortions greater than those mentioned (in this case THD is below 0.5%, which is within the standard HiFi).

Thanks Tony for the reply.

[lineup]

When looking at schematic, I say this is a very good amplifier.
I think it will work good if being built.

[hpavictor]

I suppose have no need C2 and C9 because LTP is FETs , no bipolar transistors...
Best regards , Victor