barefoot
Well-known member
I have an amp configured like the schematic below. It start's up softly, but shuts down with a big transient spike. The transient is definitely coming from the input stage. If I disconnect the 100n cap between the input and power stages I get no transient in the speaker. Also, if I tie the two inputs together, I get no transient.
The power supplies come from external sources, so I have no direct control over their startup and shutdown speeds. And it seems like the +/- 12V supplies collapse much faster than the +48V supply, since the spike is transmitted through the output stage before it has a chance to shutdown.
Any ideas on how to soften the shutdown of the input stage?
I was thinking about putting resistors in series with the +/- 12V supplies then using larger bypass caps to increase the time constant. But maybe this would compromise linearity or add a lot of noise?
Thanks!
Thomas
The power supplies come from external sources, so I have no direct control over their startup and shutdown speeds. And it seems like the +/- 12V supplies collapse much faster than the +48V supply, since the spike is transmitted through the output stage before it has a chance to shutdown.
Any ideas on how to soften the shutdown of the input stage?
I was thinking about putting resistors in series with the +/- 12V supplies then using larger bypass caps to increase the time constant. But maybe this would compromise linearity or add a lot of noise?
Thanks!
Thomas