Wed. Jun 19th, 2019


PCB design – Electronic circuit modules collection

How do I assemble power amplifier?

4 min read

How do I assemble power amplifier?

Selection of PCB ...
PCB model I chose was the mono. The reason is that mono is more to consider routing topology so that the output tends to be more stable, while the stereo more to the artistic layout.

How do I assemble power amplifier?
How do I assemble power amplifier?

R1      100K
R2,6   30K
R3,7   560
R4     10K
R5      1K
R8       2K2
R9       4K7
R10,11,12 100    100
R13,14 300         300
R15,16,17,18      0,5ohm/5W
C1,7,8                 100nF
C2,4,5,6              47uF/50V
C3                      100pF
C9-12                 3300uF/50v-1200uF/50v
D1-5                   1N4148
D6-9                   1N5402
Q1,2,4                 A564
Q3                       D438
Q5                       B507
Q6                       D313
Q7,9                    MJ2955
Q8,10                  2N3055
T                          30V-0-30V 10A

Modif version Low voltage (32V):
1. Replace capacitor 100nF to 22nF (special OCL 150W)
This is to filter out infrared signals inaudible bass and likes to annoy /
vibrate-vibrate speaker leaves.
2. Replace the bottom 47uF/50V elko capacitor-central (resonant capacitor) with 22uF/16-50V
Functions the same as no.1, and help raise the pounding bass signal (suitable for all bass  tones).
Two points are expected to keep the leaves shaking bass speakers from excessive
without reducing the production of sound (bass-treble-med).
3. Parallel R 100K with kramik 1nF (input to ground)
It is important for signal stability, reduces noise that may be entered, reducing the level of
damage the speaker / twiter and as a limiter so the output is more powerful

Modif version High voltage (42-47V):
4. Move the right foot 10K resistor to ground
This is to save electricity, and spare him from the heat
5. Elko capacitor power supply
2x4700uF 63V (max 45V transformer ct), 4700uF/80V (for voltage over 45V ct)
6. Replace 3rd elko with 47uF/100V
7. Replace the 2N5401 transistor A564 (middle base)
Transistor D438 replaced with MJE340.
D313/B507 replace with MJE340/MJE350 (inverted mounting)
Sanken Power Transistors using C2922 (preferably two sets per speaker)
8. Offset voltage of around 100mV, the power is common in OCL. To reduce it,
parallel resistor 560 (left) with around 2K ohm trimpot. Tegah two legs and edge together,
position toward the center to avoid short. Adjust trimpot so that the voltage offset
close to zero
9. Wiring for power transistor as short as possible

10. Remember, take the ground path of CT elko speaker power supply (return to zero)

Conclusion …
In the experimental version of the Low voltage
Clear, the bass is quite kicking and fluffier, the speaker leaves more stable than before dimodif.

High voltage experiments
Enough kick, stable, thick bass, lower distortion,. Suitable for speakers with a diameter of 15 “or more.

Should modif until ver low volt only (transformer 32V ct) because many false predriver transistors, eg mje350/mje340 and B649A/D669AC, this transistor physical resemblance but print different.
Keep in mind one can invite transistor transistor predriver damaged faulty driver as well, while the driver took power transistor transistor for broken anyway. Damaged power transistors usually are not alone but invites her partner (weakest) to broken anyway. Because of the small transitor fake faulty transistors can ruin all!!! Using fake transistors is not good at high voltage, before transitor on faulty signaling gasping like faltering in heavy load, smooth and less signal power output fell!!!

First grab box measuring amplifier for layout TRANSFORMER, POWER, AND PROTECTOR ELCO. Then make a hole for the bolt (drilled) in accordance with the above components.
The next step transformer plug, and attach with screws and connect with 220 V AC input current via buttons / switches do not forget the main safety fuse is also installed. Perform measurements on the output of the ac currents by lighting transformer transformer without diode / elco. Once the plug diode brigde okay with elco 6800 mf (this perwer Power supply for amps), connect from the output transformer 25 v / d 35 v, and also plug the elco diode IN 4002 and 2200mf 25v (power supply for tone control), continued from output 12v transformer s / d 18v.

After installation is complete now turn the power supply we measure the DC output voltage of the power amps for +35 V and-35V, for tone control +12 v and-12v.

For the next step attach the power module (POWER amp 300 W) the current input connection with power supply, then test by installing sepeaker in output and turn it on!. then test supplay after okay, then touch both audio input with a finger when sounded like a buzzing sound, meaning OKAY.

For the next step attach tone control with a stick / pot insert into the hole and attach the front panel amps potensio nut to tighten. And connect the input voltage to the power supply, connect the audio output to the power input module and also connect to the audio input with RCA inputs through ROTARY JACK switching. Do not forget the test also with audio (from DVD PLAYER or the other).

The next step protector pairs of speakers, connect the input current of the transformer 18 v ac, connect the input and output of the power module to the speaker terminals out. after testing was done by lighting protector, normally the indicator light flashes then stops and the relay will turn on.
Then test again with the use of multi tester (on a scale to x1 ohms input and output protector).

Then test all circuit with an audio input to the amplifier and loudspeaker pairs, when it is heard loud / clear 150W AMPLIFIER means finished.


4 thoughts on “How do I assemble power amplifier?

  1. Dear sir,
    What is the actual power consumption of this power amplifier circuit? (Not modified version)


  2. Wht kind of heat sink suitable for this? 1/2 inch aluminium 8inch is suitable for this?.I had make this quality is super hums.but the case is when I plunged without any audio signal it becomes heat in 4minuts. So what’s the problem sir??

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