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Return to BlogBattery-Powered Amplifier Known as Ruby
Posted Feb 03, 2012 at 3:59 pm
Figure 1
The circuit has been enhanced from another version of battery-powered amplifier where an input buffer feeding the inverting input and the volume control changed from the output rheostat to the type and placement while reducing the gain potentiometer from 5K to 1K Ohms.
The treble detail that enters the 386 chip is being retained by the input buffer. Nice breakup can be attained by increasing the volume. The amount of available gain is being limited by the gain potentiometer and the cleanest volume can be obtained by carefully setting thevolume and gain potentiometer. This is done by setting the volume potentiometer to maximum and slowly turning up the gain potentiometer. The maximum clean volume can be found on the point just before the sound starts to break up. For overdriving, the gain potentiometer is set to maximum and the volume potentiometer is adjusted. Doing these makes the potentiometers highly interactive.
The buffer is using MPF102 FET but other transistor may also be used such as 2N5457. The circuit was developed with the use of JRC386D although any 386 can be used. The modifications are done in Bass, Pre-set Gain, and supplied Power.
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2 years ago: What type of battery can be used for this circuit? Maybe a variable power adapter may be used so that the voltage can be adjusted accordingly