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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The IC include circuitry to block a lot, for example, prevent a spike or block the signal of the power circuit, short circuit protection and output over voltage protection circuit, out of voltage or overload. The case is not the nicest I just found it sitting around but it works fine and it looks a lot better in real life.
I started by setting up a prototype using the LM chip with regular EI laminated transformers. The most important thing is to make sure that all internal wiring is properly done. The following is a suggested layout-schematic for the power supply: This circuit is very good for a small hifi system in house, with medium overall specifications. Leave a Reply Cancel reply. Using parallel mode on an 8-ohm speaker does not increase power output considerably.
In the years since this started, power op-amps have become a major part of the DIY scene with dozens of different circuits and hundreds if not thousands of builders worldwide. Furthermore, diodes D1, D3, D6 and D8 should then be omitted. This result is shown below: First was a W x 2 Kenwood amp.
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. It is reccomended to use a. To bypass the capacitors, just run a jumper for each of them. Four FE5D diodes are used for rectification. Note that C1 must be non-polar. The voltage gain of the chipamp is determined by resistors R3 and RF, according to the following equation: Lm385 conclude from my experiences that carbon film lm38755 the right choice for the R2-R4, AB carbon composition sounded too noisy and fuzzy, metal oxide too grainy, and from a different circuit metal film too, uh, metallic and zingy.
Gainclone LM3875 PCB
Other details remain off the official record to this day: I followed the Gaincard pretty closely in using the mute switches, the attenuator, and choosing to have the same gain and input impedance. Separate power supplies can be used for each channel if desired. If your speakers are 8-ohm, ;cb only need one pcb for both speakers, with a power output of 50W per speaker.
R4 is soldered directly between the leads of the IC, which is itself tucked underneath the board together with R2 and R5. Typical l,3875, from the LM datasheet: There are some little further: Both boards will be wired in parallel mode, and then the input to one of them will be inverted for more power.
I also have pretty much the same short length of signal path and feedback loop, the latter obtained by soldering R4 directly across the chip leads.
For R1 and R5 I’m not pb. Please note that I will be using the component numbering used here throughout this page, so refer back to this diagram as needed. Figure 2 the internal circuit in LM Both the amplifier and external power supply were cased in Hammond series cast aluminum boxes.
LM Gainclone Amplifier
Attach all the S grounds together, and all the P grounds together, and then connect the two grounds by a single wire. 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’.
This capacitor prevents large DC currents from being sent to the speaker when the input ,m3875 is disconnected. Due pm3875 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 DIYers. Learn how your comment data is processed. This amplifier is compact, looks great, sounds great, has a l,3875 dozen clean watts per channel, and dissipates only 2.
Here is how to wire the board for 4-ohm speakers: The model Gaincard from 47 Laboratories lm875 a 25 Watt stereo amplifier about the size of a video cassette, powered by a large external supply.
Gainclone LM PCB – Electronics Projects Circuits
This image is to be used as a guide while assembling. I never got the combination to work cleanly. This resistor can also be omitted in most cases, which is best determined experimentally. However, if you are absolutely sure that no such risk exists, capacitor C5 can be omitted or shorted, as desired. Power supply parts list: If you do it right the amplifier is completely quiet but grounding can be a problem.