Pro Audio Design Forum

... is capable of. I do not get it. Is this the Ib in Ian's jig or the Ib in your preamp ? Instead of removing the servo IC to defeat it for test, the Deboo C can be shorted. The servo common mode output voltage will be maintained at 0V but servo correction is defeated. Doing this magnifies the total ...

... THAT1240 output has a differential gain of 2. The bridge attenuates by 4. Net servo gain seems to be 0.5. EDIT: Looked at this again. Deboo has a gain of 2 so the original net servo gain is "1." I took your suggestion terkio and removed the two fixed lower bridge arms. (20KΩ) ...

... to run without any 1240s. This also allows the servo op amp to be removed for troubleshooting or transistor matching. Better that the differential Deboo, which has a common mode gain of "1" not be "blind" to the actual CM voltage and have to have its CM reference defined by ...

... the same +1mA -1mA current throught the Rfeedback resistors. So with Rf =1K it gives +2V at the op-amp outputs. Finally: When the outputs of the Deboo send +3V -3V to skew the mic preamp, it results in +1V -1V at the op amp outputs, which results in +2V -2V at the THAT1240 outputs The good news ...

... capacitors to be monotonic to step changes. I'd rather use 1% resistors and a single C. I've only found one other reference to the Differential Deboo. There may be more now. For troubleshooting a board that someone has assembled incorrectly having them remove a bunch of ICs is a better option. ...

1) Indeed the differential Deboo is a very interesting circuit. I saw a Deboo integrator needs resistor matching. Some R1*R2/R3 that makes a negative resistor that must equal a fourth resistor R4. Does that need accurate resistor matching ...

... and R16). During my initial experiments I had the servo sense the INA output prior to the THAT1240 stages. There was nothing to pin the floating Deboo servo to ground so the added two resistors were required. Once the servo sense was moved to the final output, and the servo input became pinned ...

... and R16). During my initial experiments I had the servo sense the INA output prior to the THAT1240 stages. There was nothing to pin the floating Deboo servo to ground so the added two resistors were required. Once the servo sense was moved to the final output, and the servo input became pinned ...

... this one goes at 0V the other one goes accuratly at 0V too, thanks to how the two THAT1240 make them. Then instead of a differential symetric Deboo integrator a simple integrator ( 1 op-amp, 1 resistor, 1 cap ) could do the job. In order.. 1) It has to do with setting the Q-point (for Ic) ...

... The circuit above is virtually identical to the original in terms of noise performance. The servo has been updated to a Differential Deboo and a TL431 shunt regulator added to improve PSRR. The design is completely DC-coupled. A high pass filter response is derived by a servo. C7, ...