Servo for correcting DC offset and drift

I had a requirement to design a DC offset and DC drift correcting circuit for a project that I have been working on. One of the requirements was to correct for amplifier DC offset/drift yet allow the amplifier to operate down to DC with minimum error. I plan to use this in various projects.

The design I choose to use is pretty universal and can be adapted to work with a lot of different amplifiers with minor parts value changes.

If anyone is interested in such a design I can generate some PDF files for the circuit diagram and the two sided printed circuit board along with a short circuit description. This would take me several days since I do have some other thinks that need to get done.

Let me know if you are interested.

John Fassotte
Alaskan Audio

I have had a few minutes to post this on my site. The Leading Audio Amps Site on the Net


Unfortunately I don't find out the appropriate navigation steps. Thank you for advices in advance.
BTW - on page 385 by the book "Audio_Power_Amplifier_Design_Handbook_4th_Edition"
there is to read about the design of DC servos, but there is no advice for calculation of the resistor between DC servo output and the correction input at the LTP.
By commercial products this value goes from 1 Meg-Ohm to 10 Meg-Ohm (in case of jFET's 2SJ109/2sk389) resp. from 50K to 470K (in case of BjT input devices).