@pleurodesis Here’s the box I put it in - I had this leftover from many years ago - didn’t need the innards. Fits so firmly, it doesn’t even need screws! I drilled the holes in the bottom plate to make room for the jacks, knob, and switch.
Here’s an overhead, to get the general layout. One thing I did was put the output jack on the right, and the input jack on the left. You can see the curvature of the wiring to adjust for my preference.
Here’s two closer shots, just to make sure you can see how easy this circuit actually is. All you’ll need to get for this are:
- 9V battery
- 9V battery connector
- Two (2) 1/8" input jacks
- One (1) On/Off switch, so the circuit doesn’t suck battery juice
This pre-made circuit is all SMD, so those prongs are pretty much all that I can work with, which is why I bought this. It’s cheap, takes a bit of time to arrive from China, but it is LOUD. It has the power to drive the electret mic, then it just boosts the volume. Relatively clear, but not perfect. It’s like a really nice tape-recorder microphone preamp. I read about how many people do not like the LM386 chip, but it works for me. My ears are noisy, so it sounds like real-life to me 
I’ve got a couple more of these coming my way, and I plan to get a smaller box, use a smaller switch, and to mount the circuit board/knob better (may do that today, anyway). Heck, I might even wire the microphone IN the box, so it’s less gear to carry and/or, I’ll make a mini-mic out of just the metal end of a guitar cable.
I think this circuit is possibly dependent upon the quality of the electret you use. Not like you need to go buy a Primo or a Panasonic, but my WM-54BT sounds really nice to me. If you can hear the backyard recording, it’s what I wanted to hear.
