Installing a Pickup and Preamp in a Yamaha FG700S Acoustic

Fig. 1. Yamaha FG700S

If this post isn't all that informative, that's at least partly because I didn't take that many photos. I was so intent on not destroying the guitar that it didn't even occur to me to take photos until after I successfully cut the first hole. But first things first.

I have an inexpensive Yamaha FG700S, which is a $200 guitar new, but I got mine used for $140. For a solid top guitar, it's hard to beat for the price, and I like this one a lot. However, shortly after buying it, I wished I had bought an acoustic electric. I put it on craigslist so I could upgrade to an acoustic electric, but got no bites. So I bought a $13 piezo pickup, and a $22 preamp and input on ebay. I didn't want to spend too much, because I felt there was a decent chance that I would destroy the guitar while trying to install the pickup, since I had never done this before. And I figured if I liked it, I could always upgrade to a better preamp and pickup.

The part I feared most, obviously, was cutting two holes in the guitar. Measuring and cutting a hole in a flat plane is easy, but the preamp goes on a curved section of the guitar. I measured the preamp housing several times, placed it along the edge of the curve in the guitar body to see where it would fit best. After finding a sweet spot, I used a razor blade to make little nicks in the finish marking the border of the section to be cut out. I then marked the border with masking tape (Fig. 2).

I drilled the corners with a 1/2" bit. I started to use a jigsaw to cut the hole, but the wood was too fragile. It made a sloppy cut. I tried a utility knife to score the border of the hole, and I kept scoring until it poked through. This didn't take as long as expected, and the cuts were pretty clean. I sanded the hole and inserted the preamp. It was a little tight here and there so I sanded it again and it fit. I didn't get photos of the preamp installation, so here is the during and after shots of the input and the after shot of the preamp:

Fig. 2. Cutting the hole for the input. Installed input and preamp.

I did the same exact thing with the input. Then I plugged the piezo pickup into the preamp and stuck it under the bridge.

Fig. 3. About to place the pickup under the bridge.

I should note that the preamp came with as under-the-saddle pickup (Fig. 4). I preferred the kind that mounts inside the guitar under the bridge (Fig. 3, above), so I snipped the input off the former and and soldered it to the latter and used that.

Fig. 4. Cheap under-the-saddle pickup

Everything's in, and although I made the input hole a hair too big (so there's not enough wood in one corner for the screw to grab), it went better than I expected.

DOD YJM-308 Preamp True Bypass Mod

I don't care that much about true bypass, but a lot of people do, so I wanted to put this info out there. I just completed the true bypass mod for the DOD YJM-308 pedal, and it was incredibly easy. I used a 3PDT switch so I will have the option of installing an LED at some point, time permitting.

First, remove the original switch and replace it with a 3PDT switch. Then wire everything as shown in this photo and crude diagram (bottom view, of course):


























































It's hard to make out the wiring in the photo, and the diagram is pretty crude, but between the two of them, you should be able to discern where the wires go.

Put everything back together and that's it. All I have left to do is add the optional LED, and then use some nail polish remover to remove Yngwie's signature and name from the pedal. Again, I'm not a believer in true bypass, but I love this pedal. It was a pleasant $30 surprise (it helps to have a good amp, of course). But I'm not a signature model type -- and if I were, it wouldn't be Yngwie's signature -- so the name is going.

I should also add that the battery just fits. And I mean .00000 tolerance. So it won't bang around the enclosure when you move it.