50 Watt Amplifier
source: unknown

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This is a handy, easy to build general purpose 50 watt amp. The amp has an input for a radio, TV, stereo or other line level device. It also has a phono input for a record player, guitar, microphone or other un-amplified source. With the addition of a low pass filter at the input, it makes a great amp for a small subwoofer.

Schematic

Parts

Notes

1. I know I skipped R4. That is not a problem :-)

2. Distortion is less than 0.1% up to 100HZ and increases to about 1% at 20kHz.

3. I haven't been able to find anyone who sells a suitable T1. You can always use two 24V 5A units in series. If you are building two amps (for stereo), then I would suggest using an old microwave transformer and rewinding it.

4. Q1 and Q2 will require heatsinks.

5. You may have trouble finding U3 because it is discontinued. Please don't email me about sources...I can't find it either. A possible source was sent in by JBWilliams:

Zigma Electronics
8803 Shirless Ave.
Northbridge, CA 91324
United States
Phone: 818-772-7590