M100 - 100W Audio Amplifier [prototype project]

Thread Starter


Joined Nov 14, 2008
I have attached below a recently developed prototype project. This is an audio amplifier 100W/4Ohmi in two versions:
- M100A with transistors MJL3281/1302;
- M100B with transistor MJ15003/15004.

In PDF attached below you can see the two versions PCB.

Some useful indications for the correct construction of the project:
- To achieve PCB, print one page (5 or 7) on a glossy photo paper using a laser printer. Set the print menu option "Actual size" and the page size will be A4 landscape;
- Pads hole diameter of 0.6 W resistors and transistors in TO-92 case is 0.7 mm;
- After you have made the PCB holes, above all, fit jumpers (J1...);
- After installing jumper, then mount resistors and other electronic components.

The project can be downloaded from here (I could not attach it on http://forum.allaboutcircuits.com because the project has more than 1Mb):
I attached an image with simulated circuit diagram of the amplifier.



Joined Mar 24, 2008
Please use .zip to pack this file. I tried to download it, the hosting site is very suspicious. We will work with you, but material must be hosted on AAC.

Otherwise I will have to remove this thread.

Thread Starter


Joined Nov 14, 2008
Thanks for accepting this project.

On the issue of downloading the file above, I have mediafire.com account and I downloaded the PDF file without any problem. So no need to worry, mediafire.com is a secure website, never caused problems. If upload limit would be higher on this forum, then I would upload the file here.

However, I do not understand this part:
...but material must be hosted on AAC.
can you elaborate?

Then, if there is no another solution, I archive the PDF file in ZIP format but I still do not understand where to upload (which website?)!


Joined Nov 25, 2009
We need you to upload all the content and documentation for your project as attachments on this thread.
This way we can be sure that the links won't be broken in the future and that people won't use this site to promote their own sites.

So, please, upload the content in this thread.

The file size restrictions can be viewed in the Upload Manager pop-up window, in the "Go Advanced" advanced message editor.


Joined May 11, 2009
I have some questions regarding the heat sink(s) What kind of °C/W (thermal resistance)values do you recommend. Perhaps you have some links for datasheet regarding this matter


Joined Mar 24, 2008
Please read the rules of the Completed Projects forum.

When posting a project please include the following information:

  1. A clear title that describes the project appended by the word 'Project:', for example "Project: 555 Audio Oscillator".
  2. A list of parts, equipment, software used.
  3. Details of any theory, references or information that may be applicable.
  4. Any schematics, source code, etc.
  5. A short description of what to do.
  6. In the interests of manageability and security, project files/code/schematics must be locally stored. Links may be used to provide supplementary information, however they must not provide the substance of the project.
This project does not meet the above requirements. Therefore I am moving it to the Projects Forum. If you want to resubmit this entry please rework this thread to meet the requirements, then drop one of the moderators a PM pointing to it. If it is acceptable a moderator can move it back to the Completed Projects forum and clean up notices and suggestions (making them invisible).

All documents must be hosted locally. AAC allows for attachments and albums, use them. You Tube video links allowed, but they in no way constitute proper documentation.


Joined May 11, 2009
I noticed that you have already attached document above and I don't think it's nice that you cut the cover project.
The PDF file I created using virtual printer 995.
Regarding the heat sink, may be used, for a single channel, a heat sink like this (~30 Euro pcs. with VAT):
The front page alone took about 9 MB. By removing this the rest of the document could be posted here. For further discussion.
I have many Ebooks several hundred pages and tons of figures. And they are many times in the range 5 MB in size. I have also made quite picture intensive publications in MS Word. With a lot bit-map pictures. And then made a PDF. They all have been smaller than your document. So I am puzzled why the first page require so many MB. You will for sure be able to get the size down a lot. Work with the picture format. The hosting site used. Was not very user-friendly either. I use rapishare much less nag.
However this is your project. And you shall of course have all credit for it. Then you have managed to get the size down in order to post it here. I will of course delete my posting.