We were complaining about all the problems with piezo pickups when the idea for this standalone pre-amp came to me. It's deceptively simple... a $17 acoustic guitar pre-amp with a hacked input becomes a great EQ and signal boost. And it's all housed in a cigar box!
First of all, here's how it sounds...
I built this prototype in less than one hour. Here's how to do it:
(*Note: a piezo rod pickup is included with the pre-amp. We'll need this!)
Here's a quick overview of the process. We'll get into detail with photos after the video:
STEP 1: Cut a 3.5" x 1.5" hole in the box to fit the pre-amp. You can use a coping saw, carpenters knife or a Dremel rotary tool with a cutting disk.
STEP 2: Drill two 3/8" holes in the box, one for each guitar jack needed.
STEP 3: Take the rod piezo out of the pre-amp packaging. Using wire cutters, cut off the rod piezo pickup from its wire. Cut closest to the pickup, leaving the longest length of wire possible.
STEP 4: Pull back the ground wire sheath to expose the lead wire. Strip off 1/4" of the lead wire's insulation.
STEP 5: Solder the ground sleeve wires to the ground prong (the inner, circular portion of the jack). Solder the lead wire to the other prong (the lead prong) of the jack. This is now our hacked pickup wire and will become the input jack.
STEP 6: Insert the 1/8" plug of the hacked pickup wire into the receptacle of the pre-amp unit.
STEP 7: Install both guitar jacks to the cigar box. I would recommend positioning the hacked wire (Input) on the right side of the layout and the the black plastic jack (Output) on the left side. Also insert the 9 volt battery at this time.
STEP 8: Mark your input and output jacks accordingly. I used a woodburning pen. You could use paint or any other method. (Remember, this pre-amp in the photos is a prototype. My next one will have a cooler layout, better graphics, a carrying handle and feet!)
OPTIONAL- ADD A HIDDEN GUITAR PICK CADDY: If there's extra room in the box, you can glue an Altoids tin to the bottom. I simply used a hot glue gun to attach the bottom of the tin to the inside bottom of the box.
-Shane Speal, 2016
Good idea Shane.
It would be a good idea to have one in a pedal chain/pedal board too.
Very helpful. Thanks for posting this. I have been kicking around the idea of building a stand alone preamp, and this just cleared up any questions I had.
Is it a standard 1/8 (3.5mm) mono audio TS on the piezo? I'd almost rather get the solder yourself male connector and make up the 1/4 F to 1/8 M cable and use the piezo on the git...
It's always better to install the pre-amp directly in the guitar...however, many of us have CBGs with plain pickups and no pre-amp. This stand-alone unit allows us to properly EQ and boost those older guitars.
What I meant was, instead of cutting the piezo wire, will the pre-amp accept a 1/8" (3.5mm) male end plug?
I have a few ideas rattling around the empty corners of my noggin about saving the piezo intact for something else.
All the ones I had were 2mm not 1/8 inch. They are available from many hobby electric shops. YMMV
Neato and uber sound too. Looks like an awesome bit of kit to confound the muggles even more and enrage purists of the sacred, store-bought axe. I must give this a go. Thanks Shane, and all the best with your online concert too.
Wait'll you see what I did with a beer can...