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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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. You may not upload this material to any public server, on-line service, network or bulletin board without the prior written permission of the author. You can use a linear power supply to take at next level this circuit.

Gainclone LM3875 PCB

THD is lowest, as Figure 6 very good Frequency response. In short, no excuses. Figure 1 The pins using of LM And its its an easy and safe project to build. Can be up-graded into a pair of complete mono amplifiers by adding another Model Power Humpty. The voltage gain of the chipamp is determined by resistors R3 and RF, according to the following equation:. Four FE5D diodes are used for rectification. The PCB file is avaliable in Eagle format, ready to print.


The DRV inverts and balances the signal so that one of two non-inverted amplifiers amplifiy lm3857 inverted signal, thus allowing pcbb mode to work. Soft recovery types are probably the best bet.

For R1 and R5 I’m not sure. Typical operation, from the LM datasheet: It is provided for your personal use only and may not be reproduced, re-distributed, re-transmitted, copied or otherwise used in any form without the express written permission of the author. You can also quadruple the power into an 8-ohm speaker.


Due to the simplicity of the Gaincard design and construction, availability of inexpensive parts, as well as excellent value for money in terms of its quality and power, it soon became very popular and highly regarded among audio DIY hobbyists do-it-yourselfers or Pcg. The brown lines are jumpers that need to be wired into the circuit. Leave a Reply Cancel reply.

See below for how to wire this circuit into parallel mode. It is also possible to use a transformer with a center-tapped secondary winding. Figure 3 the schematic diagram. The transformers hummed and so did pb amplfier outputs. This page dates back to the beginning when the Gaincard was literally a black box. Furthermore, diodes D1, D3, D6 and D8 should then be omitted. The input impedance of the amplifier is determined by resistor R1. The next build lm33875 the LM chip.


The model Gaincard from 47 Laboratories is a 25 Watt stereo amplifier about the size of a video cassette, powered by a large external supply.

If you are planning on driving 4-ohm speakers, use one board per speaker, with the positive outputs wired together. Here is how to wire the board for 4-ohm speakers: The amplifier schematic is shown in Figure 1. Using parallel mode on an 8-ohm speaker does not increase power output considerably. The power supply PCB, both before and after assembly, is shown in Figures 6 and 7, respectively. pcv

LM – Power amp kit

Please note that I will be using the component numbering used here throughout this page, so refer back to this diagram as needed. C2 is most likely also omitted. You wire the two boards using the parallel mode schematic.

After comparing a 4.