Pro Audio Design Forum

Interesting.. I seem to recall another inspection of Deboo here a while back... One concern is that the noise of the following differential section is not LP filtered or attenuated by the integration capacitor. This is probably already attenuated by ...

... a THAT1570 or THAT1583 in a design without the digital gain controller and needed a servo. ...So I came up with a fully-differential form of the Deboo Integrator we used to servo the THAT1510. You may recall that the THAT1510 provides a single-ended output to feed the servo but requires a differential ...

... not be required. I'm looking at what it would take to use a 1570/1583 in this application. I think I've come up with a "differential" Deboo servo. I need to test that on a separate board. My girls are coming by for Thanksgiving today. I might be able to talk my daughter Robin into ...

... correcting the imbalance. Turns out the servo is correcting a huge current imbalance from the ECM8000. I'm seeing ~ +/- 7V at the outputs of the Deboo integrator. With dynamic mics it's <<10 mV. The ECM8000 requires a servo correction current of ~127 uA. As expected, the correction current does ...

... again I did a bit of work on the idea of replacing the differential integrator with a noninverting integrator (apparently first suggested by Deboo, it's basically a Howland current generator with a cap to common). I've done this before but never analyzed it in detail. It turns out that with ...

... values. From left to right are the passive common mode integrator (orange cap), 1510 preamp (buried under the gain switch leads), OPA2272 "Deboo" non-inverting integrator (orange cap), LME49720 low-gain offset trim stage and common mode servo and finally the flying rail power stage. ...

Visit this post "Servo with Non Inverting Differential Output using a Deboo Integrator."

viewtopic.php?f=6&t=14&start=114

... same for a given value of C. It appears to shift up an octave I suppose because the Thevenin equivalent is halved due to 1M||1M in the 1C "Deboo" vs. 1M for the 2C integrator. I doubled the C value to keep the resistor values from getting too big for an offset-compensated bipolar op ...

I like the real pole in it's input, not so sure about the positive feedback but I need to re-read that Deboo thread...

JR

... not be optimum with preamp's that have input coupling capacitors.) https://www.ka-electronics.com/images/jpg/Servo_Non_Inverting_Differential_Out_Deboo_BW.JPG Servo with Non Inverting Differential Output using a Deboo Integrator Link to printable copy: https://www.ka-electronics.com/images/jpg/Servo_Non_Inverting_Differential_Out_Deboo.JPG ...