Mic Preamp Specs

I think there's an audiophile or 2 listening. So now its time to brag.

I've finished designing my mic preamp on paper. Gonna order some parts and build a prototype.

So basically here's all of the specs on it:

Power Supply: 15VAC, low ripple, low noise. It will feed 48 for phantom power as well as, obviously, powering the preamp circuits. It will have a seperate auxiliary power for "noisy" things like LEDs and such.

Backplane: I'm making a modular preamp. Essentially the chassis will consist of the power supply and that's about it. Each module will plug into the backplane with a 15-pin connector.

Back panel: Each module will have an XLR in and 1/4" phone out. The in is "mic level" (see below) and the out is line-level.

Front panel: Each module will have:
- Level: The final level out
- Gain: The mic gain. The sound will be a function of gain and level of course.
- Input Impedence: 500-ohm or 2K-ohm.
- +48V Phantom Power
- High pass (select to cut at 160Hz or 1KHz)
- Low pass (select to cut at 160Hz or 1KHz)
- LED VU bar
- Clip LED

I'm going to put it all in a 2U rackmount enclosure with enough spots for up to 16 mics. I expect each module to cost me about $10 - $20 in parts, so no need to go straight to the 16.

I'm really excited to put the thing together. I look forward to doing the build. I'm coming in with a 15VAC AC/AC adapter because, well frankly I'm not comfortable doing the transformer / mains thing. Scares the hell outta me to be honest.

When all is said and done, I'll have a studio-quality preamp that would probably cost a good $10,000 if I were to buy retail. No exaggeration.

Next will be my mixer. I'm looking forward to that too. :)

I'm Such a Nerd

When I was a kid I was a nerd. Everyone knows that. I was picked on in elementary school. No biggie.

In my 20s I was a geek. And I was damn proud. Dot-coms were all the rage and suddenly it became cool to be a geek. Everyone was a geek.

In my 30s I'm back to being a nerd.

(Google your way around if you don't know the difference between a geek and a nerd.)

So in all my nerdy glory... well, let me back up a bit.

I like music. I like recording music and playing with that kinda stuff. However, the necessary equipment is expensive. Very expensive.

So what's a nerd to do? Build your own!

So last night I put the finishing touches on my headphone amplifier. Cost me all of $8 or so to build.

Tonight I'm going to work on my microphone preamp. That is, an amp that brings the mic to line level so it can go into a mixer. I've played with a couple of mic preamp circuits that I didn't like so I'm going ultra-nerd, grabbing my calcuator, and throwing down some mad algebra to design my own mic preamp circuit.

I'm such a nerd. But that's why you love me.

Hey SMGSI Dave, everything ok? Earthquake, that is....