DBZ - Bolero Croc Skin
So, I have this beautiful guitar, a Dean B. Zelinsky, "DBZ" Bolero Croc-Skin. It plays extremely well, it sounds great. I bought it in August 2009 and had in mind a couple of modifications DBZ did not plan to make at the time I placed my order.
The finishing of the guitar is absolutely fabulous, with a unique crocodile skin-like wood carved arched top. the neck is tight-fitted, contributing to a great sustain and nice, crisp, clean sound, with the power to saturate any amp thanks to two humbucker pickups, providing a nice sound palette.
The guitar is originally fitted with a Graph-Tech bridge it seems, and has simple 3-way switch, volume and tone controls.
I wanted a more extended sound palette and combinations; I also wanted to replace the original tuners with locking tuners.
The first change is quite easy: change the original Sperzel tuners with locking tuners. Sperzel makes the same tuners in locking version with the same tuner knobs, cool... Xavier Masson from Willow's SARL, the France representative for DBZ at the time I purchased the guitar... they seem to no longer exist :(, was kind enough to get me the locking version of Sperzel tuners. Thanks!
I installed them in a snap. I just had to drill a little deeper some of the positioning holes that receive tuner positioning pins. Now, strings are easier to change!
The next change is a little more challenging: installing piezzo pickups to get a "near" electro-acoustic sound. I already have this option from Fishman on a custom James Trussart guitar, and looked for an equivalent setup as I like the sound combinations I can get from having both magnetic and piezzo pickups. I remembered having a problem with some of the transducers of the tele-bridge (this was back in 2003) and Joe Barbieri of Fishman was very helpful, providing effective support. Turns out Fishman doesn't seem to have a gold-color "tune-o-matic" bridge to fit the Bolero Croc-Skin. I found one at Graph-Tech, with its respective preamplifier.
With a plan of disassembling several elements on the guitar, I took a look at the internal wiring of the guitar.
"Basic" I would say, yet effective and nothing I could complain about but maybe a little bit of hum when touching some areas of the guitar. I thought I could rewire this with shielded wiring and shield the control cavity while at it.
Humbuckers are -by construction- shielded so no need to shield the pickup cavities.
A quick look at the two humbuckers reveal a single output, when there are more possibilities such as reversing the pickup halves phases or use only one coil (coil-tap). I decided to make a few modifications to the magnetic pickups, so I could get reverse-phase as well as a single-coil tap out of the two humbuckers... more sound combinations. The idea is to gain access to all the coil endings, using a 4-wire shielded cable.
This actually implies dismantling the two humbuckers, a little tricky but quite feasible. First remove carefully the golden cover from the pickups; you'll need a good soldering iron to melt the solder on both
sides of the lid, under the pickups. Then expose the coils by removing the protective tape; this reveals the hot (black), ground (black) and middle connections (white) of the coils.
Using a 4 wire shielded cable, the coil connections can be extended to the pots cavity, without picking up noise. I decided to use a 4 wire shielded cable, but this can also be achieved with a 3 wire . Carefully solder and isolate the wire leads from the coils with the shielded cable wires (red = hot, green = hot-end, white = ground-end, black = ground).
All done!. The pickup is put back together with protective tape, putting back all the paraffin, and the pickup cover.
Resolder the cover, and heat gently the pickups to help the paraffin find its place again.
This needs to be done on both humbucker pickups.
And now for more challenging stuff!
Installing a set of piezzo pickups typically requires some woodworking and soldering... There's nothing complicated, but basic and good skills at woodworking and soldering are needed. If you don't feel comfortable in doing it yourself, have a pro do it for you. On a Bolero Croc Skin (or any guitar by the way) this requires a little bit of planning and a lot of care. It is very easy to scratch the varnish, miss a spot, and a wrench or a screwdriver slip and rip off some of the guitar finishing, etc... So careful, slow, ... and think twice before drilling!
The good news is that piezzo pickups come with plenty of text, pictures and step by step installation notes from the manufacturer. This makes things easy, but will not prevent from small mistakes. The Graph-Tech set I installed here exists in several variants. James Markus at Graph-tech was quite helpful in getting me to select the right set. Do not hesitate to contact the piezzo manufacturer before placing an order, they are very happy to help and generally answer quickly.
Check that you have everything you'll need before starting, and that the tools you will have to use are in good condition. Compare the bridge to the one already in place to validate if it will fit.
START! Remove strings, place it on a soft support (avoiding scratching the wood finishing), Remove the original bridge, and most likely the bridge pickup. There will need to be a way to route the wires from the piezzo saddles to the guitar control cavity. In most cases, this means drilling in the guitar body.
Drilling the body of the Bolero Croc Skin requires double thinking. Do not use woodworking drill bits!, or the Crock Skin carved wood will split around the hole you are trying to drill, ruining the job. See on the right... I stopped just before too late! No real harm done, I glued back the split wood bit.
Because of the carved surface of the Bolero, use a (new) metal drill bit! and slowly drill a hole, just at the center of the bridge position. The diameter needs to be large enough to let the 6 wires and connectors go through (one at a time).
With a wood bit this time, a perpendicular hole is also drilled from the bridge pickup cavity towards the hole just drilled under the bridge. The two holes must meet to enable the wires to route into the pickup cavity.
One by one, the wires are routed through the holes, into the pickup cavity. Then to the guitar control cavity. It may be a good idea to remove the pots and wires before if you plan to rewire the guitar anyways, this will make the whole job easier. Copy the intonation from the original bridge to the new one, this will make the guitar re-tuning easier and faster. The bridge is set in place, but not the way it is on the photo shown here! One of the little things that are not mentioned in the pickups documentation and you have either to know or to find out somehow.
Once I had reassembled everything, I was not satisfied with the piezzo sound (thin, kind of absent). I contacted Graph-Tech, and Morgan Ahoff from Graph-Tech support team confirmed me by looking at the picture on the right my bridge had the wrong orientation. The intonation screws need to face the magnetic pickups (which is not that usual as far as I know). I changed this later and sure enough the sound is quite different (I mean... much better).
The saddles are pre-mounted on the bridge and are balanced to match the EADGBE strings, so reversing the orientation is not a good idea.
One more drilling moment through the guitar body... The piezzo volume will have its own pot. Again, use the right drill bit, depending on your guitar finish. A wood bit may be the best (go very slowly with these...) or your worst enemy in the case of a carved surface as the one of the Croc Skin.
I did not make the same mistake... and this time used the right drill bit.
Now on to some soldering. The Graph-Tech booklet that accompanies the bridge and preamp from Graph-Tech has lots of drawings and explanations to connect the wires for the piezzo saddles and combine magnetic and piezzo. The pre-assembled wires are quite helpful too.
In my case, I wanted to have a lot more changes than just installing piezzo pickups, which is why I worked on the magnetic pickups. I combined reverse phase, single coil tap and piezzo, with the help of three pots with a ON/ON switch on each of the pots. My best source for HW is Stewart MacDonald, great and fast service, great support, quality and dependable stuff.
I include the schematics for the new magnetic wiring. Nothing complicated here, but you need to put a lot of attention in soldering the wires together or to the pots, carefully identifying what goes with what before soldering. You don't want to come back to this again and again... Make sure you use shielded cable! and connecting all the grounds, including the ground wire connected to the guitar metallic parts in a single point. In my case I used the top of one of the ON-ON switches.
Note that I also shielded the cavity with adhesive copper foil, before re-installing the guitar electronics.
One special note: although the Graph-Tech set comes complete, I had to change the Graph-Tech pot by a different one, as the arch-top of the Bolero Croc Skin needs a long shaft pot. I could not find a 250K long shaft, but a 500K works fine for Graph-Tech. I just duplicated the original wiring, using the original wires from Graph-Tech.
The control cavity quickly becomes very busy... with things back in place and all wires soldered, it's time to restring the guitar and check for the new sounds. Check the reverse phase on the magnetic pickups work as expected, the single coil tap, volume and tone controls, no hum. The magnetic volume to the min, check the piezzo, mix the magnetic pickups, check magnetic reverse-phase, etc... All all right? Great, otherwise, back to schematics, wire verifications, or as in my case, understanding why the piezzo sound was not as expected -This needs to get in bold face in the documentation Mr Graph-Tech! -.
When all done, it's time to re-tune the guitar correctly, reset the strings height to comfortable levels, re-tune the intonation, and play!
A Thank you note: to Dean B Zelinsky for a fabulous guitar, Jeff Dale (DBZ) and Xavier Masson (Willow's) for helping me in the acquisition of the guitar all the way to France. The staff at Stewart MacDonald for a great selection of products for guitar repairs and modifications, and James Markus and Morgan Ahoff at Graph-Tech for their support and help. You can check out the sound of the guitar (and the JamesTrussart as well :-) ) on many tunes I played with daily-blues.
Note: I described here what I did. The author cannot be held responsible of any wrongdoing would you try to bring similar modifications to your guitar.