Double Bass Inexperienced luthier building an electric cello

[bopeuph]

Hey guys,

I've started a few threads asking questions about this, but I think it's time to start one following my progress, and to ask questions here.

I've been looking around at electric cellos for the last year or so, and while there's a lot of different things I like, nothing has everything. I like the NS cellos with both magnetic and piezo pickups, but I don't like the shape of the instrument. I like the shape of the Yamaha Silent Cello, but no magnetic pups.

I've thought about buying one of these instruments and adding what I like to them, but they are, first of all, not cheap; and secondly, I wouldn't feel right about gouging out instruments at those price ranges and ending up with botched work.

Anyway, I'm starting by collecting the materials. I bought a cello that a kid smashed the top on. The neck and back are still in decent shape. The back would make a good template for the body measurements, and the neck is going to be recycled for the instrument.

My dad has a customer that is really into woodworking, and he has a shed full of hardwoods, so I'm going to pay him a visit and see what I can grab up. I know he likes mahogany, so I might get some of that.

As for the frame, to keep costs and weight down, I think I'm going to make it with a much lighter wood, like pine.

Essentially, I'm going to go with the design those cheap Chinese instruments have, but I am using decent wood instead. Basically, this shape:

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Anyway, I've already been working at getting the neck off. I should have done that before taking the back off; now I have no leverage to slide it off, so I'm trying to loosen the glue as much as possible with the denatured alcohol right now. If anyone has suggestions as to getting the neck off, that would help. I'll post pics soon.

 

[Heifetzbass]

Should this be in the Luthier's Corner?

Anyway, if you aren't using the neck block in your project I would probably cut it out. Use a Japanese dozuki saw. Any remnants of the block can be planed off using a low-angle block plane.

Or if you don't want to do that get yourself a syringe and hot water and start working it into the joint. If it's hide glue then it will dissolve and break out.

Good Luck,
BG

 

[bopeuph]

Thanks, Brian. I figured this is better in the EUB corner since it's an electric instrument I'm building. But you're right about the removing the neck part; that's why I put a post specifically for that in the luthier's corner.

I actually used a chisel to chip the block off piece by piece. There are chips left on the joint, but I would guess that the glue will be loosened easier now. If this is hide glue, it's really strong, but at least the wood on the neck stayed put.

Anyway, the plan is to cut out a joint in the wood of the solid body.

But the next step is to locate some wood. My dad's customer doesn't have any hardwood at the required length, so I'm going to stop by one shop today; but even if they are still open (which I'm not sure), I remember them being expensive, so I might not get the wood from there. I'm in my hometown right now, and there's a yard in Orlando that has a much better reputation, anyway. So I'll look there when I get back in town next week.

I'm thinking perhaps a mahogany middle with maple on either side, about 4-5 inches in width for the main body. Seriously thinking about a taper to keep it lighter. Any suggestions here? Would this kind of lamination be the right way to do it?

 

[Heifetzbass]

Depends on the finish you will ultimately go with. I think mahogany would be a good wood to use. I don't think lamination is necessary unless you don't have the thickness. If you are going to paint over it, it doesn't matter what is underneath, but if you are going to clear coat then I would make attractive wood selections.

BG

 

[bopeuph]

Yeah, going with a clear coat. So a single piece is fine? How thick do I need to go to withstand the tension?

 

[Heifetzbass]

I can measure the thickness of my Yamaha silent cello on Monday.

 

[bopeuph]

Awesome, thanks.

In the meantime, I'm probably going to gather the lumber for the frame, which will be a 2x10 pine board to be light. I'm thinking about making it in one piece and attaching it to the back to add depth for both the feel and for a more secure dovetail joint. I know it would probably be much heavier than attaching the frame to either side, but I like the fixed point much more than a removable piece like the Yamaha.

Thoughts?

 

[scojack]

I would probably go for the maple if it was me, although mahogany would work just as well.
My last EUB was around 2/2.5 inches thick but the carved top made it look much thinner.
You can laminate pieces together if you can't find a piece thick enough or ....if you want to make it look good with a clear coat, stick a nice piece of curly maple on the top. Quartersawn timber is probably best as it's a little stonger and less likely to warp through time especially if it's one piece. I'd probably laminate a few pieces together if it was me.
Just watch the weight

Good Luck and keep us posted !!
Ian

 

[bopeuph]

I was also told I need to pay attention to the direction of the grain. I assume I just want the grain to run lenthwise, parallel to the strings. Correct?

 

[scojack]

Yup that would correct.

 

[bopeuph]

Awesome. Thanks guys. Now that I'm back in Orlando I'm going to swing by this place called Woodcraft later in the week. Both guitar and violin luthiers, including Guitar Factory, recommended them. My dad's customer only had one piece of mahogany at the right length, but about only an inch thick, and we were both too busy while I was in town for the weekend to meet, so I'd just rather shop around.

Anywho, got the neck off; had to saw the button off because I will probably have one on the instrument and needed the pattern of the whole back and the glue was way too strong to weaken. Too bad the back has cracks now; I should have been more careful and worked harder to get it off cleaner to possibly use it on the instrument. I might still use it anyway, so we'll see when I get to that point.

 

[kozmikyak]

Just so you know, what NS Design does with its pickups--there is a piezo tab or disc under each bridge foot, and for good bowed sound they are out of phase with each other, but for good plucked sound they are in phase with each other.

On my Ergo cellos (7-string) I use a "sandwich" of wood/pickup/wood/pickup/wood on each bridge foot, and set up one pair of pickups as in-phase, and one pair as out-of-phase (by turning one piezo disc upside down in the out-of-phase pair, doing it by swapping wires results in ground hum) and wiring the whole ball of wax to a stereo jack, so it can be separately preamped for bowing and plucking. Then the performer can separately route bowed and plucked notes to various effects/board inputs.

 

[bopeuph]

That's actually pretty interesting.

I'm pretty surprised at the cheap Chinese piezo elements you get on eBay--the Chinese electric cello I have has one of them, and it doesn't sound bad at all, especially with fdeck's preamp in the chain.

I was actually thinking about using one of them, and also adding a magnetic pickup for another signal option. I know there are some out there designed for cello, but I am kind of curious to see how, say, a set of Quarter Pounders would sound on a cello. How I want to mount them is a question I have yet to figure out.

 

[bopeuph]

Okay, here's some pics of the progress so far. Not much, but it's great to have it logged here as I go:

First, here's the cello I bought as the basis. The neck is being reused, and the back might be as well. The back is also the template for drawing the shape of the frame.

Here's the cello with its top off. Ooh, la la!

The neck. I had to cut the button off, since I wanted to keep it intact and it was being a major pain to get off without breaking.

Here's the lumber I bought today. They only had one piece of standard maple, and a piece of curly, so I bought one of each, and mahogany for the middle. These are 3/4" thick and 6" wide, if I recall correctly. The sides is just a 2x10 piece of pine from Lowe's, which will be a frame like the picture in the first post. Altogether, the lumber was about $85. Combined with the $75 cello, I'm already up to $160. Didn't think the lumber would cost that much! The hardwood did already come pre-cut and pre-planed, though. Which is great, since I don't have a planer here.

Anyway, I plan to layer it like it is in this pic to have a deep neck pocket for the joint. It's pretty heavy right now, but there's going to be more than half of that wood gone, so I hope it won't really be that heavy.

 

[kozmikyak]

There's nothing wrong with cheap piezo elements. Pickup topology and wiring has a lot to do with making them sound good, as well as properly buffering them with a high-impedance preamp. The elements I use are from inexpensive piezo buzzers.

 

[bopeuph]

That's good to know. I'll definitely come back to that again.

Speaking of pickups, here's a rough design as to what I plan on doing for the magnetics. I am going to build up to the strings with the leftover wood, where I will route out a spot for them. Of course, the "housing" will be contoured and I plan on carving it down to look like a part of the instrument, and not something stuck on randomly. This is going to be tricky, since I'm not really a luthier and there's nobody out there that's tried exactly what I'm doing, as far as I can tell.

Then again, I'm debating on lowering the angle of the neck drastically to be able to mount the pups directly to the body. But how much will that affect the design of the instrument and its playability, especially placement of notes relative to the shoulder bouts? Also, how will that affect the pressure on the bridge for the piezos?

 

[bopeuph]

Okay, FINALLY getting around to gluing the boards together.

Took me a while to collect enough clamps. My landlord has woodworking tools, but his shop area is more of a storage area now, so I have to fish out tools as I need them.

I thought he had a bandsaw, but all he has is a jigsaw. It'll do, but I think using it will be trickier than a bandsaw. I'd cut the pine while the hardwoods are curing, but I think I want to use the clamps to hold the board down while cutting.

Anyway, after the boards are laminated together, I want to cut it to size. Any idea as to how wide the top of the board has to be for the neck pocket to hold steady? I'm thinking about having the top at 3 inches and flaring it out to about 5-6 inches at the bottom.

 

[bopeuph]

So here was a suggestion by a Baby Bass maker:

Cut a hole in the neck heel and add an extra piece of wood down through the neck, and fit it into a carved out hole in the body like a Baby Bass. I would also need to take the fingerboard off and drive a stainless steel wood screw down in there to keep it in place.

Maybe I should have just carved the neck myself from the beginning?

Anyway, here's his sketch:

Here's one that another luthier sent me in a message:

I think that I had a somewhat easier task as I made the neck from scratch. I made a slightly elongated neck as you can se here (very non-traditional):

And to add to the ”non traditional” aspect I screwed the neck (and used glue too of cause) from the part overhanging the ”body”. The screw heads were later on covered by the fingerboard and completely invisible. I used to have a CAD file of this instrument but I seemed to have lost that when I got a new computer… I would gladly have shared that with you. I think I would have approached your build in a similar way, but trying to figure out a way of screwing the neck to the body from the body side, and then hide the access holes with veneer or maybe wooden cover plates

And this is what I was planning. Finally made a sketch of my own: