45W Single Chip Amplifier by LM3876

[guclusat]

This circuit is based on the National Semiconductor LM3876. This device is capable of delivering as much as 56W of continuous average power into an eight ohm load with 0.1% THD from 20Hz to 20Khz. Be sure to provide an adequate heat sink for the package.
Use log pots for volume, bass and treble. A stereo amplifier can be built using ganged pots and a Stancor 402 transformer instead of the 401.
Note that the delivery of power to the speakers is primarily a function of the power supply voltage and capacity in Class A amplifier. In our case, we’re using a +/- 33 volt volt supply which is designed around a Stancor RT401 transformer. Use extreme caution when working with line voltages

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[uydudoktoru]

LM3876 Gainclone Amplifier

The amp is based on the Project 19 PCB, so uses a pair of LM3876 (or LM3886) power opamps, run from a ±35V supply. I used a cut-down P88 preamp PCB because I only wanted one preamplifier stage, but the entire board can also be used. Alternatively, the P19 amp can be run at higher gain than normal, alleviating the need for a preamp at all. The down side of this is that the noise level will be higher, and background noise may be audible with efficient speakers and/ or very quiet surroundings.

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