HOLN POWER-I - Since I decided to name my own projects with the HOLN brand, one of the first projects were to make one 200W power amplifier. Once at my friend's home in the 2007 new year's day, his neighbour just placed huge loudspeakers with forró and funk carioca, we could not hear what we were thinking, and you cannot imagine how this music is horrible, so I told him that I will make a blockbuster amplifier to him. To fight this crap with the pure rock 'n roll music.

    All information I could get, Gerber files, and schematics, are given on the lines below.

    Any suggestions, questions, PLS mail me. I will try to answer what I can.

    These are partially the results I got until now.

Gerber files for the amplifier and Bargraph indicator All for the final version.

Amplifier schematics Here the schematics are of the final version. Diode D19 and C21 were added because in the high peaks, the voltage over the relay dropped to the limit of the relay action. With the capacitor it will be avoided.

Bargraph schematics  R4 & R5 values must be changed accordingly with your power rating. RV1 is only for fine tunning. Is better to use LM3916 instead of LM3914, so you can read in Watts, using a linear scale. LM3914 is voltage scale(linear) , LM3915 is logarithmic VU scale (for dB) and LM3916 is power scale (quadratic).


Printscreen of a 3D view of the project made with KiCAD



 To try to increase the temperature sharing of the differential input pair, I just joined them with thermal grease and one heat shrinking tube. This increased the drift by 20mV with the temperature. By the way, the two transistors were from the same LOT. This might helps, but I did not tested with different LOTs to see if there is too much difference.

On the image above you can see the 2 transistor joined.

Since I could not find a heathsink big enough, the solution was to tie 2 together, and used 2 3/8" screws and nuts.

    There are some mods to be done the original project, but the gerber and sch given above are ok. I did not tested this new files, is up to you if you want.






Almost finished!!!


Now with the black electrostatic texturized painting....

quite agressive appearance...