Ramsey Electronics BN9 Stereo Amplifier User Manual


 
MICROPHONE AND AUDIO INPUT CONSIDERATION
You may choose almost any transducer to convert sound into an electrical signal for your BN9. Some
of the transducers are as follows; ceramic, crystal, dynamic, or even another speaker! You may also
use audio from any other source as well (other than a zillion watt per channel power amp!)
GAIN CONSIDERATIONS
In applications where you don't need so much gain, such as amplifying earphone outputs, you may
wish to omit the pre-amplifier stage. This is done by removing (or just plain not installing) the preamp
transistor and substituting a jumper (made from a scrap component lead) for R1. This allows you to
still get the full 2 1/2 watts of audio output but reduces the total gain to 50. There is no point in feed-
ing the LM380 more audio signal, it just results in poorly distorted audio with no additional power out-
put gained.
TROUBLESHOOTING
Problem: LM380 gets really hot, and then quits!
Solution: Cool your jets! You are probably running maximum voltage and maximum power for too
long. Either reduce the voltage to 10-12 volts or reduce your volume level. You may need to replace
the LM380.