Pro Audio Design Forum

Today we have better opamps available but I'd still put that preamp [P100] up against all comers.

You like that one better than the P10? Probably a better question posed in that thread but I had to ask.

OK, you made me look. I had a hunch I'd find it in the phono preamp post. For the benefit of our readers it's A2. R17 and C9 form the passive input LPF. R14 and C11 form the output LPF. http://johnhroberts.com/P100.gif There's a lot of LF gain in A1 which makes the Vos requirements of A2 far less de...

The LT1012 is only 0.1 V/uS. I do like the idea of the passive LPF ahead of the integrator. My old servo has a passive LPF in series with it's output too I think I used that in a 1512/1570 summing amp similar to the SSM2017 application note. Too bad (affordable) BIFETS lack the DC precision for many...

It's about 3X faster SR (0.8 V/uS vs. 0.3 V/uS) than an OP07 which work fine as servos. (Though the OP07's DC performance could be better which is the point of this post.) I wouldn't be nervous about using this part in an integrator with <<< 20 Hz cutoff having to slew a few 10's of millivolts. You ...

Just saw the press release for these in Planet Analog. They have 36V capability, low Vos, fairly low Ib, low drift and are available in singles, duals and quads. If available and resonably priced (both big "ifs") these might make good servo amps particularly when duals are needed. http://w...

Thanks for the update Waveterm. My Lowes sold out of those 60W Feit A19s a few weeks ago and I have not seen them since. Glad you found some. The A19 40W Feit's seem to still be available. On the upside Lowes seems to have good stock of the GE 62180. Those and the Philips are beautiful in table lamp...

You may recall all of my noob' questions last year pertaining to this idea. In my spare time I went ahead and designed something, and then had a colleague (ex-Digidesign engineer) write the code for the DAW control. I built a prototype, and am now taking it around to studios for test drives. I did ...

If trying to mimic classic transformer mic preamp sound, it seems you want a step up transformer not a simple 1:1 to fully capture the characteristic transfer function. I agree. And as you also point out then you have this added gain and high impedance loading requirement. At that point the 1570 is...

OK, just had some more coffee. T-bias isn't going to raise the differential resistance, just the common mode which doesn't help the transformer loading.

Thank you Wayne and JR for your answers. I have another question, perhaps risking to be burned on fire or killed with stones, but here we go.. =)) I think you may mistake us for some other place :-) I think RE6B is mis-drawn WRT the transformer secondary in the figures. You're really going to have ...