diyAudio (
-   Solid State (
-   -   Servo for correcting DC offset and drift (

alaskanaudio 16th November 2001 03:01 PM

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

Geoff 16th November 2001 03:17 PM


I'm not too concerned about the pcb layout, but would be most interested in a copy of the schematic and circuit description.


alaskanaudio 17th November 2001 03:05 AM

The circuit and short explanation

I have had a few minutes to post this on my site.


Geoff 17th November 2001 10:36 AM


Thanks for posting the details. More reading to do this weekend :-)


tiefbassuebertr 31st July 2013 07:56 AM


Originally Posted by alaskanaudio (

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).

tiefbassuebertr 31st July 2013 08:27 AM

in this case there is an additional thread here on diyaudio:

All times are GMT. The time now is 05:27 PM.

vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright 1999-2017 diyAudio

Content Relevant URLs by vBSEO 3.3.2