dr pepper
Advanced Member level 1
A receiver I threw together using an Lm380 for the audio amp is misbehaving, it goes unstable at anything other that quiet volume levels.
Without the speaker connected it shows no oscillations on the 'scope, and a little RF, the detector (AM) filter isnt removing all the Rf.
So I tried a larger cap on the detector filter, but had to go so high the audio is really muffled, same goes for restricting the bandwidth of the amp by using a cap across the i/p's as per the datasheet.
So I bodged it putting a choke as per a passivle crossover inline with the spk.
What would be a cleaner approach to this, preferably without resorting to an op amp.
Without the speaker connected it shows no oscillations on the 'scope, and a little RF, the detector (AM) filter isnt removing all the Rf.
So I tried a larger cap on the detector filter, but had to go so high the audio is really muffled, same goes for restricting the bandwidth of the amp by using a cap across the i/p's as per the datasheet.
So I bodged it putting a choke as per a passivle crossover inline with the spk.
What would be a cleaner approach to this, preferably without resorting to an op amp.