Pro Audio Design Forum

The advantage of the Birt is that the second op amp's noise appears in common mode, not differential. (Assuming good R match.) Interesting, good to know. Otherwise, I see no advantage in the Birt. We've talked a lot here about the advantage of passive input poles on servos which the non-inverting &...

the two amplifiers can be thought of as being in series I see a Birt topology. I do not use the Birt to make differential outputs from differential inputs. I use twice the same op amp circuit, one to derive Outa = K x ( Ina - Inb) the other to derive Outb = K x ( Inb - Ina). This is perfectly balan...

This is to use at the inputs of a mic preamp, for -hopefully- CMRR enhancement. Is this, good ? https://www.mouser.fr/datasheet/2/410/media-346070.pdf It is not specified as a CMC, but it has 1:1 turn ratio, is small, is specified over 20Hz 50KHz I was unable to find Common Mode Chokes, clearly made...

The relays are latching type. OK, to be honest, I quickly gave up figuring out this contraption. IIRC the author doesn't go into the "why" but I think it would shed a whole lot of light on his motivation. Could be the author doesn't know the "why", his motivation being to have s...

Relay-Based ON/OFF Flip-Flop Remembers State During Power Failure http://www.electronicdesign.com/analog/relay-based-onoff-flip-flop-remembers-state-during-power-failure https://www.electronicdesign.com/sites/electronicdesign.com/files/IFD2671_Fig1.png https://www.electronicdesign.com/sites/electro...

Thanks for these reviews on ADA4522-2 and OPA2189 for dual DC servo uses. Giving more than datasheets. Good to know about beats from asynchronous clocks, an effect one can hardly guess beforehand. BTW: Which dual servo do you use ? A differentiel Deboo integrator ( that has one cap ) or a more usual...

Thanks for your answers.
I forgot I do have a microchip PIC developement kit Unused for so many years.....
It might very well support what I need for audio projets.

@JR. Wonderful, I am glad to see a DSP with a DAC built in, a perfect solution for this and many more.

EDIT: I spotted dsPIC33F 4 bucks !
Can you recommend a kit with a DSP and DAC, I could play with, plug and play ?

This thread revived an old time where I struggled with LF oscillators for measuring distortion with the double T bridged filter. The best I achieved was nothing to praise, distortion measurements capable of 0.1 %, that was good enough for me. I remember the struggle to achieve an amplitude stable an...

I just discovered the LMP2021. It has very low offset and it is pretty quiet. http://www.ti.com/lit/ds/symlink/lmp2021.pdf Fantastic Vos. Trouble is, for me, I need +15V -15V op amps. I just couldn't get the choppers quiet in my circuit, though they are also working for me. How bad is it ? How to c...