Delay time through power amp?

[sumaudioguy]

Using global feedback there is some delay between the time the signal appears on the first active device and the time the global feedback reaches the feedback active device. Do you all with the simulators or any of the rest with real circuits have values for delay times?

Am getting like 4µs through a 130 watt/8 ohm power amp and wonder how this compared?

Thanks to all for thoughts and info.

 

[djoffe]

A rough estimate

Consider the whole amp as a single pole filter..yes, it's a very rough approximation...anyway...

for frequencies below the three dB frequency, the delay of a single pole filter is 1/(2*pi*f3db). As an example, if the amplifier were 3 dB down at 50000 Hertz, then its delay below 50000 Hertz would be about
1/(2*pi*50000)=3.18 microseconds.

 

[sumaudioguy]

Consider the whole amp as a single pole filter..yes, it's a very rough approximation...anyway...

for frequencies below the three dB frequency, the delay of a single pole filter is 1/(2*pi*f3db). As an example, if the amplifier were 3 dB down at 50000 Hertz, then its delay below 50000 Hertz would be about
1/(2*pi*50000)=3.18 microseconds.

So I have two stages in the amp. The input stage and the emitter follower output stage. The input delay is 2.1µs from input through to the last gain stage output and the double emitter follower output stage is 1.9us. Hummmm.

Thanks for the input. I know there is delay in the device which apparently needs that time added in. The open loop bandwidth of the amp is 85kHz at -3dB with a gain of 95dB. That would be 1.8µs,

Obviously I need to do more testing with other circuits including this new output stage which uses much faster transistors...150mHz outputs and drivers instead of the old 4mHz ones. That will surely be faster.