[Design in progress] Varimu preamp

Ashayar · Oct 10, 2017

Hello everyone!

Yes, it take me a lot of time, too much passions, and a baby coming really soon

Here are the last schematics of my project.
The last changes I made was to add relays for the input pad, the phantom power etc, and a partition noise killer on each EF183.
Now I am searching for a solution to polarise both EF183 at the same current, I am searching some informations about how to design a variable current sink and I'll put one on each cathode of the EF183 to force them to work at the same point.

I thought about something else. Do you think it is worth it to make a full differential structure?
I am asking this because I saw on the G9 or the Redd47 that it was not differential, and If I decide to use the same idea, I could simplify my structure a lot

See you all!

François

Ashayar · May 3, 2019

Hello everyone,

I finally found some time, and I finished the first full iteration of my microphone preamp

Here we gooo!
I've got to check the resistors power handling, and to select the components, and then I'll be able to create the circuit board.

Have a nice day!

Ricardus · May 3, 2019

Ashayar said:
Hello everyone,

I finally found some time, and I finished the first full iteration of my microphone preamp
Here we gooo!
I've got to check the resistors power handling, and to select the components, and then I'll be able to create the circuit board.

Have a nice day!

Also, people around here like circuit boards. So if this turns out to be a really cool preamp I am sure people would buy boards from you.

Ashayar · May 3, 2019

Ricardus said:
Also, people around here like circuit boards. So if this turns out to be a really cool preamp I am sure people would buy boards from you.

Hello Ricardus,

If it's working well, every source for my version of the PCB will be shared