Vermes
Advanced Member level 4
The overall concept
An amplifier of small size and power of 50-100W was the aim of this project. Well known system LM3886 was used for this purpose because it is cheap and simple to make. Another reason why LM3886 was chosen is good performance of the tip.
Construction of the amplifier
An old housing from Unitra tuner was used in construction. It was renewed by adding new lacquer. Printed boards were made in a standard thermal transfer method.
Power amplifier drives the teroidal transformer 250W voltage and it is filtered by two pairs of capacitors with a capacity 4700uF. Later, a soft-start was added to the transformer, which is only 250W. Also pre-amplifiers were added in this construction. They were made on systems tl072 and tl074. As the drive system, an old antenna signal indicator was used. The indicator was previously converted and adapted to the construction.
Also input selector controlled by an electronic Izostat was used.
Listening impressions
The amplifier plays much better than for example Diora WS442 and the sound is pleasing to the ear.
Here are some pictures:
Link to original thread – Wzmacniacz na LM 3886
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