Stereo 50 Power Amplifer
Leak power amplifiers required only 125mV for full power output. This is much more sensitive than most other power amplifiers, and be inconvenient when using the power amps with other pre-amps, or when directly connecting a CD player to the power amp. It means that any small amount of noise in these sources can become audible, and the volume control may need to be operated only over a small section of its full action.
A circuit for a low-gain Leak Stereo 50 amplifier has been developed. There are a number of ways of doing this, including replacing the first stage with a low-gain triode. However, the approach adopted here is to:
The modified circuit requires about 550mV for full power output. The modifications are easily implemented, and can be removed later if it is desired to return the amp to its original circuit.