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Permalink Reply by Ron "Oily" Sprague on July 18, 2013 at 10:16pm

Groucho, 

You could use the Search function at top right of the page to show you something like this:

http://www.cigarboxnation.com/video/comparing-cbg-pickups

or this:

http://www.cigarboxnation.com/photo/new-neck-fit

or this:

http://storage.ning.com/topology/rest/1.0/file/get/306066179?profil... This is an order of 4 Spectraply bridges with piezo rods that Randy Bretz made for me. The piezo rods sit under the bone saddle in a slot cut into the bridge, and he drills a tiny hole to thread the wire through to connect to the jack, volume pot, or whatever.

Another discussion of how Randy recommends doing rod piezos:

http://www.cigarboxnation.com/forum/topics/first-build-5?commentId=...

Now to answer your questions in order, to the best of my limited, mostly secondhand ability:

• What's better, a piezo disk or rod?  Are magnetic pickups that much better?

There is no better, really. It depends on the type of sound you wanna hear. If you're playing acoustically, then no pickups are needed at all! ;-) Disc piezos are known for extremely high impedance, and picking up every unwanted vibration you can imagine, but they are an extremely cheap way of getting what many people refer to as a vintage sound. Most people install them in one of several ways: couple of layers of double stick tape, so the disc can be moved to different locations under the lid, bridge or neck, for testing or focusing on bass versus treble vibrations; sandwiching between wood, felt, leather, Duct Tape, etc, to reduce feedback; installing in a hole cut into the neck or bottom of the bridge, secured with hot glue or silicone, then with more hot glue or silicone dumped on top of that, for the same reason. Lots of ways to go.

Many people feel the rod piezo is a step up in sound quality, as the string pressure on a rod-under-saddle- build like Randy's transmits the vibes you want, that of the strings. I have several commercial gits and a coupla CBGs that use this exact same technology, to great effect. 

Magnetic pickups are regarded as a further improvement, in that in this case you are transmitting sound not directly by vibration, but through varying the magnetic field of a pole magnet by putting the vibrating string in that field; this sends a small current through the wires of the pup to the jack to the amp, where it can be boosted and shaped for pretty much whatever soudnd you want. There are all kinds of mag pups, from the "pro" homemade kinds that Ted Crocker, Bob Harrison, Skeesix, Elmar Zeilhofer (his Flatpups are loved by lots of builders here - not that all you other pickup builders aren't loved too for your pickups!!! - for their extremely low profile, and thus lack of need to cut a pickup hole in the top), and a host of others too numerous to mention by name here, to "standard" Fender-type single coil pickups, used in a variety of creative ways, to P90s and mini-humbuckers. Search around, and you'll begin to see what I mean.

• How do you prep a box & neck to install a magnetic pickup and where should it go?

Depends on the type of pup. As you can see from the vids and pics above, many builders put a mag pup in the traditional neck location for a bluesy warm tone, while others place it down near the bridge for a brighter tone, while others do both. Some cut a slot in the neck to accept the pup, others go a step further by installing wooden wings to that so that the pup height can be adjusted (I think Dan Sleep may have a vid showing this, and I know he has pics of some of his builds that show it - chekc out his Profile page), pretty much every one who does that type of install cuts out a pup-shaped hole in the top; the list of ways to do this is endless. Same for piezos discs and rods, except those are usually hidden out of sight beneath a saddle, bridge or lid. Some are embedded in the neck itself, others are attached as described above.

• Do you know where I can find instructions for installing a magnetic pickup?

Look around the site. There is a pickup Group here on CBN, and another one which has wiring diagrams from Seymour Duncan and other commercial builders showing how to wire them up. All fo the aforementioned pup builders, plus guys like The Phrygian Kid, Craig Mayhem, etc can tell or show you how they have installed and wired up theirs.

• Do piezos only work well in bigger/deeper boxes?

They work in any kind of box, or any other place where you want to transmit vibration. Smaller boxes tend to give you a much quieter, more banjoey or mandolin sound, all else being equal, while larger deeper boxes tend to give you warmer, deeper tones. Scale length, strings, tuning all become highly important when looking at box size. 

• Do I need a magnetic pickup if I have a smaller or harder box?  Do they work well on larger boxes too?

Need? Not necessarily. Depends, again, on what kinda sound you're looking for (an endless quest, trust me. That's why I have 20+ gits and 10+ amps in the house, while others are even more addicted to the quest for tone. :-) But a mag pup can seriously improve the tonal capabilities of, especially, a small, quiet box with a thick lid. Yes, they also work well on larger boxes, too.

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Permalink Reply by Groucho on July 19, 2013 at 2:48am

Wow.  Thanks for the all the info!

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Permalink Reply by Skeesix on July 19, 2013 at 6:47am

I include installation instructions with my pickups.

Skeesix

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Permalink Reply by Gary Merrithew on July 19, 2013 at 11:54am

 When I make CBG for friends I use magnetic pickups, that way I know they can plug into about any amp and not deal with the piezo howlin or feedin back. That being said, a piezo for 3 bucks and a quick trip to radio shack is pretty hard to beat if you want to play through a really clean channel. The last couple piezo builds I did, I used styrafoam , cut a hole in it and duct taped the crap out of it, and glued it in, it did help with the feedback,,, a little ;). I'm rambling sorry,,,, uh,,,, yea what Ron said go with that :)

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Permalink Reply by Randy S. Bretz on July 19, 2013 at 12:04pm

I`ve used mag pickups on a few builds, but I still like rod piezo`s as my number on choice for builds. Easy install, no grounding of the strings to worry about. They sound just as good as some mags. Can make awesome looking bridges to go with the look of the build. Plus there`s no feedback like the piezo disc`s can make when put inside the box.

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