The Gainclone. Introduction: Background Info: Construction Notes. Introduction. The model Gaincard from 47 Laboratories is a 25 Watt stereo amplifier. Check for Samples: LM The LM is a high-performance audio power LM to reduce the effects of PCB trace resistance and inductance. PCB for 56W Audio Amplifier using LM HiFi Amp. For LM IC. High quality FR4 double-sided, plated-thru and tinned holes, with conformal coating.

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So it is almost a complete IC without additional circuitry, thus leading to yet more user-friendly and convenient.

LM3875 Gain Clone Amplifier Project

The case can be left floating or attached to the signal ground. Separate power supplies can be used for each channel if desired.

The power supply is very simple. This projects have the Frequency response and the total harmonic distortion: After comparing a 4. The DRV inverts and balances the signal so that one of two non-inverted amplifiers amplifiy an inverted signal, pbc allowing bridge mode to work.

This site uses Akismet to reduce spam. The rest is a simple matter of deduction.

This chip delivers unbelievable quality, especially for it’s low power levels. If you do it right the amplifier is completely quiet but grounding can be a problem. I compared a few different amps.


Diodes should be rated to at least 5A. Top Background Information Some things we know for sure: There are some little further: The wiring is done like this: Figure 3 the schematic diagram.

Two ground points are defined, the base of R2 is the signal ground S and the base of R3 the power ground P. Many electronics circuits and projects for learning in simple ways. LM Gainclone Amplifier Indroduction: As a result, you will need to use four amplifiers two boards per speaker and a circuit capable of inverting the signal to one of the amplifier pairs.

Also, the concept is so minimalist that it leaves very little room for major mistakes so you should be able to freely indulge in fearless experimentation with different values and brands of capacitors, resistors, etc. The signal into the ultra sonic filter circuit, which include of capacitor C3 and resistor R3 and R1 To act to prevent the radio noise signal and attenuate RF signal is lower, before the signal will into pin 7 thus this have high gain up to 25 times.

You can also quadruple the power into an 8-ohm speaker. Therefore, you would want to choose an R3 value greater than 4. This image is to be used as a guide while assembling. An extremely low parts count also allowed for a very compact and customizable design, as evidenced by numerous websites, fora and blogs dedicated to audio DIY and Gaincard clones aptly named ‘gainclones’ or ‘chipamps’.


Soft recovery types are probably the best bet. For a given capacitance, a lower voltage power supply gives a softer, more relaxed sound.

I preferred the two big bridges, which sounded more open and powerful, but clearly there is room to experiment. The amplifier schematic is shown in Figure 1. Rather than using one board for stereo, you will need 2 boards, each one running in a parallel mode. Rather than connecting the ground to a speaker, you take the positive output of the resistors from one amp and connect them to each side of the speaker.

Gainclone amplifier circuit,stereo 40W using LM

Figure 4 the PCB layout. Given that this is a very simple and newbie-friendly amplifier, which has been successfully built many, many times with identical or very similar results, your satisfaction with the project should be guaranteed. The amplifier can be used in the inverting mode, as well.

This result is shown below:. Salim Khan 22 May Reply.