Search found 67 matches

by ilya
Tue Jan 19, 2010 8:37 am
Forum: Pro Audio Design
Topic: Old: A Direct-Coupled Input-Capacitorless Active Mic Preamp
Replies: 212
Views: 316051

Re: A Direct-Coupled Input-Capacitorless Active Mic Preamp

Wayne, thanks for comments. I've uploaded an updated circuit with a differential servo. The image is too big to post in the forum, so I linked to the PDF instead: http://www.dontsov.ru/DIY/DCPreamp/Main_preamp_circuit.pdf It just occured to me, that maybe I should take the signal to the inverter AFT...
by ilya
Tue Jan 19, 2010 5:41 am
Forum: Pro Audio Design
Topic: Old: A Direct-Coupled Input-Capacitorless Active Mic Preamp
Replies: 212
Views: 316051

Re: A Direct-Coupled Input-Capacitorless Active Mic Preamp

Wayne, thanks for pointing that out. I've checked the specs for regulators and they show a typical load of 3.5mA for regulation. I've adjusted the circuit as follows: http://www.dontsov.ru/DIY/DCPreamp/PSU_update.JPG Here's the PCB layout if anybody's interested ;) http://www.dontsov.ru/DIY/DCPreamp...
by ilya
Sun Jan 17, 2010 4:14 pm
Forum: Pro Audio Design
Topic: Old: A Direct-Coupled Input-Capacitorless Active Mic Preamp
Replies: 212
Views: 316051

Re: A Direct-Coupled Input-Capacitorless Active Mic Preamp

Wayne,

Thank you very much for the comments. I'll make the corrections you pointed out.
Meanwhile, here's the quick preview of the PSU board. I think it's tougher than the preamp itself...

Image
by ilya
Sun Jan 10, 2010 1:27 pm
Forum: Pro Audio Design
Topic: Old: A Direct-Coupled Input-Capacitorless Active Mic Preamp
Replies: 212
Views: 316051

Re: A Direct-Coupled Input-Capacitorless Active Mic Preamp

I've put up the preamp schematic with another servo suggested by Wayne. Here it is: http://www.dontsov.ru/DIY/DCPreamp/DC_pre.JPG Let me know if there are any glaring errors in the circuit... EDIT: I'm going to place as much controls on PCB as possible. I think I'll go for Grayhill 71PCB right angle...
by ilya
Fri Jan 08, 2010 5:44 pm
Forum: Pro Audio Design
Topic: Old: A Direct-Coupled Input-Capacitorless Active Mic Preamp
Replies: 212
Views: 316051

Re: A Direct-Coupled Input-Capacitorless Active Mic Preamp

JR, I've played with the fullwave circuit and tried to substitute inverter or LED driver with a BJT. I must conclude that I'm not very proficient at circuit design and I'm not ready to modify this excellent circuit to get rid of an op-amp. I think I'll go with the existing circuits as building block...
by ilya
Wed Jan 06, 2010 3:52 pm
Forum: Pro Audio Design
Topic: Old: A Direct-Coupled Input-Capacitorless Active Mic Preamp
Replies: 212
Views: 316051

Re: A Direct-Coupled Input-Capacitorless Active Mic Preamp

Wayne, I think that negative peak detector would suffice. However, these circuits both waste an IC "real estate": in the first one it is 1 unused op-amp and in the second it's 1 unused comparator. The last circuit you proposed looks very reasonable. But returning to the first one, I thought that may...
by ilya
Tue Jan 05, 2010 5:21 pm
Forum: Pro Audio Design
Topic: Old: A Direct-Coupled Input-Capacitorless Active Mic Preamp
Replies: 212
Views: 316051

Re: A Direct-Coupled Input-Capacitorless Active Mic Preamp

Wayne, I'm looking at this preamp and I like it more and more. I'm thinking of building something like a 4- or 8-channels pre (hope to fit it in 1U case) and I'm leaning towards your design. I thought that some sort of "Signal" and "Clip" indicators would be useful, and I remember the circuit you su...