Need help with a push pull amplifier problem

[unclejed613]

just remember when troubleshooting that your rail voltages "walk" with the audio. it makes for a "whiskey-tango-fox" moment the first time you stick a scope on the rails and see them following the audio...

 

[furlow]

Finally a schematic. Notice that this can be pretty much the same as Furlow's original circuit. It needs a bit of refinement (emitter resistors, trim the bias, lower the supply to something reasonable like +/-40) but it would *work*.

one quick question I intend to use more then one amp from the same transformer (which to let you know i hunted down a 25-0-25 300va on ebay so would give ruffly 35-0-35 dc)....

just remember when troubleshooting that your rail voltages "walk" with the audio. it makes for a "whiskey-tango-fox" moment the first time you stick a scope on the rails and see them following the audio...

..... you mention the rails voltages "walk" with the audio which gives me the impression that if I tried to use this configuration with more than one amp circuit there would be problems?

 

[unclejed613]

"..... you mention the rails voltages "walk" with the audio which gives me the impression that if I tried to use this configuration with more than one amp circuit there would be problems?"



each amplifier needs it's own power supply secondary. it doesn't necessarily mean they need their own transformer, but because it reduces cost to use off-the-shelf transformers, that's usually how it's done.