Sunday, August 01, 2021

Power Amplifier Class AB G77

The following is a series of Power Amplifier class Ab G77 by Kartino S., for the embedded features there is an input balance that can be changed directly to unbalance with this additional jumper, then there is a led indicator, speaker delay. DC Protection and input limiter features, this limiter can also be bypassed, by removing this jumper. there are features that adjust DCO and also adjust the bias.

For the final transistor using 8 sets of final transistors. .can use Toshiba, NJW, sanken allegro, etc. can be adjusted to the power supply voltage.

And the following is for the PCB layout design, the dimensions of this PCB are 27.5mm x 7 cm, for the heatsink or cooler later, you can use the 2U size heatsink,  with a length of 30cm.

And I share this PCB for free, the download link can be downloaded at the end of the post.

Power Supply Max 100VDC CT Recommended 90VDC CT. Minimum 10A.

Build and tested amplifier video:Power Amplifier Class-AB G77


Gerber Files: PCB Layout Class-AB G77  Buy PCB at

Sunday, July 18, 2021

DIY Super Powerful Monoblock Car Amplifier Subwoofer - Class-D

DIY Monoblock Car Amplifier Subwoofer - Class-D
Hello, in this post, I will make a monoblock amplifier for subwoofer speakers that use a 12V power supply or battery, which I will later install in the car.

Class-D Subwoofer Amplifier

The following is a schematic of the amplifier block. there are several parts, namely the section for the dc to dc converter, from 12V it is increased to 45-75VDC CT voltage for the main supply of the amplifier, for the protection supply and 12V bias I also made from the secondary output of the transformer, so that it is isolated from the primary power supply voltage for supply ic opamp I use R Shunt + zener which is taken from the main supply. oh yes, for the amplifier, I use a class-d Halfbridge Dual feedback amplifier designed by Mr. Kartino S. For the totem, I use 2 TC4420, and use 4 mosfet. The mosfet that I will use later is 90n20, and I will use the amplifier later to handle speakers with an impedance of 1 ohm and even this amplifier can also be used for 1 ohm and below. for the subwoofer filter, I use the same as the one posted in the tda7294 subwoofer amplifier. For protection, I added a DC protector, an Over-current protector.

12V Class-D Subwoofer Amplifier

The following is the PCB layout that I have designed, the PCB size is 33.7x14.5cm, I made the size to fit the heatsink or cooler from the car amplifier that I have so that it looks like a car amplifier in general. I made a dual-layer PCB design, I will share the layout for free, you can click the link at end of the post. For dual layer PCB printing, I recommend JLCPCB because the price is sufficient and the work is fast, less than 2 weeks the PCB from JLCPCB has arrived at home. 

My primary elco uses a capacity of 6800uf voltage 25V and secondary Elco 1200uf 80V. The inductor for my filter uses an inductor rated at 8uH. I made 2 versions of the PWM, namely the TC4427 totem and the a1015 transistor. Friends, you can also download the PCB layout at the same link. PWM uses the TL494 IC and without using a pin header so it is directly soldered to the mainboard amplifier PCB. The trimpot on this PWM serves to regulate the secondary voltage output.

Next for the converter transformer, I use a green toroid with a diameter of 6.5cm. For the primary winding, I use 1.5mm wire for as many as 6 copies with a total of 6 turns. for the second part, I used 7 duplicate 1mm wires with 27 turns. and for the extra, I use a 1.5mm wire wrapped around as much as 10 turns.

For the fuse, you can adjust the capacity of the battery. my secondary diode uses a mur1560 diode, and 8 MOSFET transistors for the converter I use fdp054n10.

Next we test first whether the converter is working or not, install the fuse on the secondary output. then input the black 12V supply for the red min for the + and this small cable for the brake or remote voltage, for testing it can be jumped directly with the + voltage.

Then turn on the amplifier, if the Over Current led is active, set the trimpot to Over current, turn it to the right so it's not too sensitive.

 If the OCP is off then the protect led will light up for a while, and a small relay will activate. the sign is that the converter is working, and the red led near the speaker relay will also light up briefly and turn off, the led is for the protect indicator on the speaker. protect will work when the speaker is on or delayed, and if the speaker output is more than 3V DCO.

Next, we check the voltage at several points before installing the components, this is the op-amp supply voltage on the subwoofer filter, which is + - 30V and 15V to ground. if it does not come out can be checked on the Zener diode under the R shunt.

then this is the main supply voltage around 56V DC to Ground. This voltage can be set on the trimpot on the PWM board as I described earlier.

And this is the bias voltage and supply protector around 12V DC. if it does not come out the possibility of IC 7812 is damaged, for the TL071 opamp supply voltage on the amplifier section, the voltage reads 25V DC + - and to the ground is around 12VDC. if it doesn't come out it's possible that the Zener or rshunt is damaged. If the measurement point has been met, then we will install the IC before installing the CLass-D mosfet we check first whether the PWM amplifier is working or not, we can check using an oscilloscope, attach the probe to the low side MOSFET gate, and ground to the ground amplifier. Inject the input with the audio generator, then the gate will output a PWM signal with a freq according to the input freq. 

the amplifier driver is already working, then we turn it off first and install the MOSFET. MOSFET uses 4x 90N20 MOSFET.

 then we test again, attach the oscilloscope probe to the prefilter, and ground to the ground amplifier After that, turn it on again, now the PWM has come out, I set the freq at 160kHz, to set it, I can change the value of the resistor with the set freq label. If we hold the input, the duty will widen, this is a sign that the amplifier is working.

For more details check this youtube video:


Full schematic and PCB Layout Gerbe Files  Monoblock Subwoofer Car Amplifier Mainboard + PWM board

Friday, June 11, 2021

Subwoofer Controller Low Pass Filter

Subwoofer controller preamplifier, this circuit functions to filter low tones specifically for power amplifier use with subwoofer speakers, works well which is equipped with a 30Hz-500Hz frequency setting feature, Subsonic Filter feature to remove frequencies below 20Hz, Bass-Booster feature, to increase bass gain. And also volume settings.

Below the Subwoofer Controller Circuit Diagram:

Subwoofer Controller Low Pass Filter
In the circuit above there are 4 pieces of IC Dual Op Amp, IC U10 serves as an input buffer that can be Stereo or mono by entering both inputs with audio sources. So if this subwoofer controller circuit is combined with other tone controls, it will not affect the other preamp circuits.
IC U1 for low-tone frequency filters that can be adjusted in frequency on the potentiometer R45/R10, the R is the same only differs in the PCB design so that it can use 2 types of potentiometers. But I recommend using 20K ohm size.

IC U2 as a Subsonic filter, which can be activated or bypassed on the SUBSONIC switch.
IC U3 as a bass booster to add gain that can be activated or bypassed on the BOOST switch. gain can be set at R55, the greater the value, the greater the gain, and vice versa.

IC can use JRC4558, NE5532, TL072, MC33078, etc.

Here's the PCB Layout for the schematic above, it's working fine.

PCB Layout Subwoofer Controller Low Pass Filter
Tested Video:

PCB Layout can be downloaded in PDF/Gerber file format:


Friday, May 28, 2021

Power Amplifier TDA7294 BTL Stereo

Power Amplifier TDA7294 BTL Stereo

TDA7294 BTL Stereo Amplifier, Often it takes a sound that is strong enough on the speaker (loudspeaker), so that the information voiced can reach the user's ears (listener). Either information in the form of music, news, or audio sound in any form. For this purpose, several manufacturers have produced ICs with a large enough output power (100 watts or more), so that users no longer need to assemble large power amplifiers using transistors. Because one of the advantages of using an IC as a core component is that it only takes a few additional components to assemble an amplifier circuit. 

One of the ICs that produces output with large enough power, but has a small physical size is the TDA7924 with BTL Application.

The following is the TDA7294 power amplifier scheme which is in BTL and already has a Stereo Amplifier:

TDA7294 power amplifier scheme which is in BTL and already has a Stereo Amplifier:

To make it easier to assemble the power amplifier the TDA7294 Stereo elcircuit also adds a single layer and double layer PCB layout, along with the PCB layout.

Power Amplifier TDA7294 BTL Stereo PCB Layout Single Layer:
Power Amplifier TDA7294 BTL Stereo PCB Layout Single Layer:

Power Amplifier TDA7294 BTL Stereo PCB Layout Double Layer:
Power Amplifier TDA7294 BTL Stereo PCB Layout Double Layer:

Video tested TDA7294 BTL Sereo Amplifier

Download TDA7294 BTL Stereo


Monday, May 03, 2021

STK 4132 II PCB Layout Single

Power STK (STK4132, 4142, 4152, 4162,4172, 4182, 4192, II) has been used for a long time, which used to be generally used for high-end brand amplifiers or audio which are said to deserve to be called Hi-fi audio even now. And according to the specifications, this STK 4132 power has THD (Total Harmonic Distortion) or the language is very small, the signal defect is very small, which is at least 0.4%, so it's no wonder it has low noise and linearity of sound or clear audio so it may be very worthy to be called Hi-fi audio.

IC STK4132 already contains 2 power amplifiers that are integrated in an IC, so to make a stereo Power Amplifier with an output power of 40 Watts, just an IC STK4132 is enough.

Here is the complete circuit diagram:


The following PCB Layout STK can be used for IC STK 4132, 4142, 4152, 4162,4172, 4182, 4192, II

STK 4132 II PCB Layout Single

This power amplifier is very suitable to be juxtaposed as a satellite speaker to assemble your own 2.1 audio because the sound is clear.

PCB Layout Master Mixer Single Supply 12V

The master mixer circuit is a series of buffers and an increase in the audio signal gain which can be adjusted by the volume pot. The master mixer is classified as an active circuit that uses a dual op-amp IC and the voltage used is 12 volts. In addition, to amplify the sound that usually sounds very weak/small when inputted to the amplifier, and also as an amplifier from other weak audio sources.
This kit is widely applied to power amplifiers so that the sound will kick even more.
This circuit is very helpful and makes your Power Amp louder.

PCB Layout Master Mixer Single Supply 12VDC  Fixed, The layout of resistors that have no value can be filled as desired, for example, 1K Ohm - 10K Ohm, the resistor affects the gain.

PCB Layout Master Mixer Single Supply 12VDC

Wednesday, April 14, 2021

The Differences Between Converters and Inverters

 Does your business work with electrical devices in any capacity? Then you’re probably familiar with the terms converter and inverter. While these devices have similar names and somewhat similar functions, there are some key differences. But let’s start with the common point—converters and converters both convert voltage. What sets the two apart? Well, converters convert an electrical device’s voltage from AC to DC. Inverters, on the other hand, convert the voltage from DC to AC. Essentially, the two devices work in opposite directions.

The Differences Between Converters and Inverters

Why do I need a converter or inverter?

If your business works with electrical appliances and technologies in any way, it’s crucial to know the difference between converters and inverters. When powering up any electrical device, you’ll want to make sure you’re supplying it with the correct level and type of voltage. That’s where converters and inverters come into play. Almost all electronic devices require converters to run safely. For example, to run a desktop computer, you’ll need a converter to change the alternating current running from a power point to a usable direct current at a suitable voltage. Inverters are a little more complicated. You’ll generally find these devices used to convert energy from a battery, fuel cell, or solar panel to AC electricity, making the energy usable in the electric grid. Uninterrupted power services or UPSs also use inverters to access AC power when mains electricity is unavailable.

All about converters

There are a few different types of converters. These types are:

● Digital-to-digital converters, or DDC

● Digital-to-analog converters, or DAC

● Analog-to-digital converters, or ADC

Digital-to-digital converters change digital data from one type to another. Digital-to-analog converters change digital codes to analog signals—you’ll often find them used in computer sound cards, CD players, and digital music players. Analog-to-digital converters convert analog voltage into digital numbers that represent the voltage or current’s magnitude. 

Converters boast various uses, including converting AC to DC energy, detecting modulated radio signals, and providing polarised voltage for welding. Converters can also perform DC to DC conversion. For example, a 12V to 24V converter can double DC power, reducing the necessary wire size in boat, car, and truck electrical systems. This type of conversion can help businesses save money on wire gauges.

All about inverters

Inverters take power from a DC source, such as a solar panel or battery, and convert it into usable AC power. Inverters are especially useful when travelling, allowing car and campervan owners to power AC appliances such as coffee machines and toasters with a DC battery. As an example, an inverter can ‘invert’ power from a 12V DC battery into 110V AC energy, allowing you use to 110V power outlets. Inverters are also often used for induction heating.


In short, converters change voltage from AC to DC, while inverters change voltage from DC to AC. Converters can also be used to perform DC to DC conversion. With your new knowledge about the difference between these two options, you’ll be able to make an informed choice when purchasing inverters or converters for your business.