Hi,
is there a way to use an dc-servo for an audio-opamp if I use the opamp in inverted mode?
If I would use that walt jung servo (Page 26 / 6.24 Fig. 6.17), one would get a low-pass around 40Hz (39.2k/0.1uF) attanuated by 1M for a given signal.
If there are more, or even more serious drawbacks I'd like to know...
The offset I have to deal with is aprox. 20mV, so I guess it will be next to useless to feed the compensation pins (1/5), right?
So, any hints for me?
Rüdiger
is there a way to use an dc-servo for an audio-opamp if I use the opamp in inverted mode?
If I would use that walt jung servo (Page 26 / 6.24 Fig. 6.17), one would get a low-pass around 40Hz (39.2k/0.1uF) attanuated by 1M for a given signal.
If there are more, or even more serious drawbacks I'd like to know...
The offset I have to deal with is aprox. 20mV, so I guess it will be next to useless to feed the compensation pins (1/5), right?
So, any hints for me?
Rüdiger
Andrew,
I did not mean the servo-F, but if you connect the servos output to the summing point, and feed the signal to that inverted input, the signal in turn sees that low-pass, meaning, only Fs under 40 Hz will pass unattanuated, and that would barley be acceptable.
Rüdiger
I did not mean the servo-F, but if you connect the servos output to the summing point, and feed the signal to that inverted input, the signal in turn sees that low-pass, meaning, only Fs under 40 Hz will pass unattanuated, and that would barley be acceptable.
Rüdiger
Inverting or non-inverting, it doesn't matter.
If you check my gainclone you can see how I have done. The pcb can handle both inverting and non-inverting amps with or without DC-servo.
http://home.swipnet.se/~w-50719/hifi/gainclone
Why don't you test my simulation? I have used the freeware LTSpice from www.linear.com
If you check my gainclone you can see how I have done. The pcb can handle both inverting and non-inverting amps with or without DC-servo.
http://home.swipnet.se/~w-50719/hifi/gainclone
Why don't you test my simulation? I have used the freeware LTSpice from www.linear.com
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A DC-servo is just an active feedback element and this is very pedagogical if you simulate it. You'll notice also that care must be taken if the servo has less supply voltage than the main amp.
What happends if you put out 10-20 Hz at full power? You must deside for yourself lower limit in frequency at full output power when the servo is not yet saturated => distortion.
What happends if you put out 10-20 Hz at full power? You must deside for yourself lower limit in frequency at full output power when the servo is not yet saturated => distortion.
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