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Converting an Acoustic Guitar to a Bass, and String Selection
- Thread starter CTGull
- Start date
I've gotten the idea of taking a cheap (read: crappy acoustic guitar shaped object) and trying to make a 30" scale bass with it, for the heck of it. Some are probably right to cite concerns about tension, but I'm not certain that at 25" or 25.5" you're ACTUALLY going to see a real increase in total tension. But don't get me wrong - I haven't done any math either.
You could move the bridge 5" farther away (adding a bridge plate underneath. But the intonation would be off all over the neck since the frets were located for a 25" scale. There are calculators out there to figure out the fret positions. It would be interesting to see how far off the notes would be. I'm guessing it would probably be ugly.
Probably fairly ugly indeed, 30" is a fair bit bigger than either 25.5 or 24.75 or whatever scale the manufacturer decided to come up with for whatever guitar it was. I know there are two numbers floating around for fret scale calculations. One of them was 18 - the other one was 17.817. My first instrument I just went with 18, because I honestly didn't know any better. Most instruments since were 17.817. In a nutshell, just calulate the distance between the nut and saddle (the scale length), by dividing it by either of those numbers, subtract that from the total, and lather rinse repeat as necessary. To my understanding now, one works towards compensating even further for various things, but honestly I was never a pro and I've been out of that game for a pretty long while.
edit: I wrote out that technique pretty crappily - what I meant was, divide the total scale by either 18 or 17.817, that would be the point of your first fret. Subtract that distance from your total scale, and continue for as many frets as necessary.
Here's my acoustic guitar-to-bass conversion, featuring a tall saddle and a tailpiece made from a hinge and a hard drive cage.
So far, I can use any strings that will fit the tuners, I just bend the strings to a 90 degree angle before I cut to length.
Sounds pretty good, but might try amplification next.
So far, I can use any strings that will fit the tuners, I just bend the strings to a 90 degree angle before I cut to length.
Sounds pretty good, but might try amplification next.
No worries. There's plenty of crazy goings on here. Those are more in my skill set then pretty stuff anyway.
BG side is mostly pretty accepting of any weird whackery. You might get told why one may not work well, but it will often be a "voice of experience" post in that case by someone who tried it, not "never do this because it's not the done thing." The DB side luthiers are more easily bent out of shape, as a rule, but not all of them.
I'm fond of nylon tapewounds, and have heard good things about using them on ABGs (though I don't know with short-scale ABGs if there are more issues with them) but I haven't built an acoustic yet, and when I do (I actually have a project inching closer to the stove though not actually on a burner yet) it's likely to be either flatwounds or full-on DB strings (also flatwounds), as my current band is really into me using the bow on the DB, and the acoustic project thing will be a different take on the DB, functionally, with a slightly different form-factor for easier transport, and perhaps some mechanism to save my fingers the current issues I'm having (trigger finger and not really being all that fond of pretending I'm good at fretless-ness) while sticking to the basic low register (I hardly touch the G string as it is.)
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My suggestion is to either buy a Taylor baby bass or base your build on that specific bass. Because it’s a guitar scale bass guitar.
For a one off use I have used round files from the hobby store that taper down to a point. I use calipers to find the spot on the file that corresponds to the chosen string gauge and wrap masking tape there. I file the slot going up to the taped section and use an old roundwound string to lap in the slot with a tiny bit of abrasive cream.
That's a good point. I have many of those files. Depending on the string gage I can rock some of my existing nut files to open the slot slightly. The only one I can't cover is the E, at .090" or .095" (for the LaBella CB40's or CB60's). All the small round needle files I have are .120" dia. and taper very quickly. That would work great for the LaBella Silverbacks or flat wounds. I would have to get .095" nut file @ $17.77. Not bad. That drops the estimated cost to build the bass at about $100. Not bad.
The hard part is deciding on what vintage Yamaha to use. I wanted to use a smaller 000 size, to match the YamaGull. But a larger dreadnaught would certainly give more low end and output. That's more important. They're all spruce plywood tops. I'll be sure to select one with mahogany plywood back & sides.
If you use the String Tension Pro website you can check the tensions at the shorter scales. But that only works for steel strings. They don't know the tensions of the LaBella nylon core strings. I'd think if you know the diameter of the nylon core you should be able to calculate the tensions pretty close. Unfortunately, the String Tension Pro isn't working for me. I select the scale & tuning, but at the screen for the End Type/Construction/Material after selecting Bass Ball End it doesn't give me any options for Construction. I can't go any further. Tried Chome, IE & Edge.
You obviously aren't the curious type who likes to fix & build stuff. Those who try and fail have learned more than those who never tried at all.
I was going to mention that also. Before I got actual nut files I made due fairly well with needle files and a set of welding torch tip cleaners. As long as the slots angle down towards the headstock and the strings have plenty of wraps so they put a decent downward pressure on the nut bass strings seem to do ok if the slots are a little loose. Not flopping around in the nut but you can get by with less then perfect in a pinch.
I was thinking just to check the balance of various string sets. I checked one set yesterday and I think the tensions varies from 12 lbs to 18 lbs!!
Unlike the 6 string guitar. A slightly loose nut slot can cause the string to buzz. Especially if it's not sitting right at the front edge of the nut. Been there, done that. More than once...
