Two channel portable balanced mic preamp

[ricothetroll]

Have you already built it? It's a good thing you can use Vactrols (why two?), even if I would have put them to control the gain of IC7A.

No I haven't yet. IMHO, you have 2 solutions with IC7A :
- You use the vactrol across R5+gain pot, but the efficiency is then dependent of the setting of the gain pot
- You use the vactrol to replace R40, and set it always ON when no limiting occurs. This eats a lot of current...

In my case I had to practically develop a limiter, using THAT's 4315 and with help from their support. If it works fine, it might end up as a limiter AN at THAT.

Is you S/N still correct with low level mics ? (worst case scenario would be an M160 for example) As someone here said, you have to set the gain of the first stage very low to be sure nothing could overload it. It then ruins your S/N for low level signals.

 

[carlmart]

We are developing our pcb yet, so I can't say how the present settings will work.

But I have used this same setup with a previous preamp, using an SSM2017, and it worked quite well with dynamic mics. But I never tried any M160 or any ribbon types.

Though it will be my first experience with a limiter.