Electronics > Projects, Designs, and Technical Stuff
Fet preamp circuits for dynamic microphones
Bassman59:
--- Quote from: computerlen on August 02, 2020, 11:30:09 pm ---I find it easier to send schematics at computerlen@hotmail.com. I won't be coming back to this site for another few weeks.
--- End quote ---
Ask here, engage here. I don’t know why anyone would want to continue this as a private discussion.
Zero999:
--- Quote from: fourfathom on August 02, 2020, 09:16:33 pm ---
--- Quote from: Zero999 on August 02, 2020, 08:51:56 pm ---A BJT input amplifier is better for low input impedances, such as a dynamic microphone. A J-FET input amplifier, is better for high input impedances, such as a condenser microphone.
--- End quote ---
I'm just curious, how would a common-gate JFET compare in the low-Z case (source is the input, drain the output)?
--- End quote ---
Since the voltage noise is between the gate and souce, it won't make any difference to the noise voltage, whether it's common gate or common source.
computerlen:
I would like to converse via my email address about my circuit design. I can more easily send the wiring diagrams back and forth to the more knowledgeable tech about my ideas of improving the circuit. Also, if that tech is is willing to go to the trouble of writing to me directly, I am happy to share the schematic. I really do not want too many people to see this diagram.
magic:
--- Quote from: Marco on August 02, 2020, 11:53:25 pm ---A BF862 is so low noise in the audio band it simply doesn't matter any more.
--- End quote ---
That might be true.
Just the Johnson noise of a 150~200Ω dynamic mic is more than 1.5nV/rtHz.
Do they make refrigerated mics to cut it down? :-DD
Zero999:
--- Quote from: computerlen on August 07, 2020, 10:39:00 pm ---I would like to converse via my email address about my circuit design. I can more easily send the wiring diagrams back and forth to the more knowledgeable tech about my ideas of improving the circuit. Also, if that tech is is willing to go to the trouble of writing to me directly, I am happy to share the schematic. I really do not want too many people to see this diagram.
--- End quote ---
The downside is no one else can see any of the schematics and make suggestions/corrections. Suppose you and I discuss this via email and I make a few mistakes in my responses, you probably won't spot the. Now consider the same scenario, but on the forum, where everyone else can read and correct my errors.
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version