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

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.

Thursday, April 01, 2021


 TDA Power Amplifier with Subwoofer filter (active) , this the circuit diagram for TDA7294 Subwoofer:


Sunday, February 28, 2021

Stereo TDA7294 + Stepper High Efficient Amplifier

Hello elcircuit friends, this time elcircuit will post the TDA7294 power amplifier scheme added with the stepper circuit, this stepper circuit serves to increase the efficiency of the TDA7294 amplifier because it uses 2 power supply voltages, namely low voltage, and higher voltage. so the voltage when standby or output is still below the clip point of the low voltage, the medium used to supply the amplifier is the low voltage. and if it approaches the point of clip, the supply voltage will increase linearly (Class-G Amplifier). The following is a schematic of the reference IC TDA7294 datasheet which changed the value of the part so that it is easy to find the components. In the final stepper transistor section, you can use the TIP3055 / 2955, 2SC2922 / 1943, etc.

TDA7294 + Stepper High Efficient Amplifier

To facilitate assembly, elcircuit also provides a PCB file in the form of a Gerber file as shown below. The power in this TDA7294 + stepper amplifier circuit can produce up to 180W. Low Voltage supply 12VAC-25VAC Higher voltage supply 32VAC-45VAC.

PCB TDA7294 + Stepper High Efficient Amplifier


SCHEMATIC Stereo TDA7294 + Stepper High Efficient Amplifier 

GERBER Stereo TDA7294 + Stepper High Efficient Amplifier