c.2012 Upright Banjo Bass (modifications)

I first posted this bass back in August 2012 and since then I've been playing it now and then to practice on but haven't taken it out to play for shows at all. The Baba Yagas (I'm a member) will be hosting an open mic series next month in a place with very limited stage space so it seemed like time to revise and improve the design so I could use it rather than my big old 3/4 upright (or at least have the option).

The biggest benefit of this instrument is that it can fit in the back seat of any car and is relatively thin front to back (yet it still has a 26" wide rim) which makes storage on-stage about three zillion times easier than that of a true double bass. At the same time it has tremendous volume (between 1/2 and up to 2/3 that of a double bass) and a full, round tone. I haven't played a single "acoustic bass guitar," even nice and giant ones, that can even come close to acoustically getting an upright tone and volume level, which is the whole reason I built this guy in the first place!

However, the original design for this had a few problems that I needed to sort out. I wanted a slightly taller bridge to get more of an upright break angle (and thus increase projection), I wanted to try a resonator back on it (I did and actually found volume and projection suffered and it was clumsier to play), the neck/"dowel" coupling drifted a little bit after a while forcing the strings too close to the bass side of the neck, and the bridge design was good for tone but pushed the head in too much. I knew that was going to be a problem from the get-go, though, with such a huge rim.

I fixed the bridge design by cutting a taller U-shaped base out of maple and installing a flat 1/8" thick piece of spruce to the bottom of it. I kept the spruce long and rectangular to keep with the minimalist look of the instrument. Surprise, surprise -- the bridge is far more stable and the tone and volume improved right away with this mod. Note that I just fit this bridge today so I haven't yet cleaned up the look of it -- I just did a minimal amount of sanding to get it cleaned-up after rough cutting it.

To counter the sideways pull of the strings I installed strap buttons to adjust the angle that they ran at. This centered the strings on the bridge. I may install one for the A string as well, just for looks, as it does not need it. To be honest I could have just installed a cello or small bass tailpiece and just adjusted how it hung on its "tailgut," but I like to have as few moving pieces on an instrument as possible and this also improved back-angle on the bridge vs. a tailpiece design.

I also modified the neck joint area with some added washers to add some extra back-angle at the neck. This helped to make the instrument "feel" more like a double bass, too, with the neck coming back from the body at a steeper angle.

I also finished installing 100% proper banjo hooks for head tightening. This cleaned up the look of the instrument. I was using a mix of big drum lugs and banjo hooks before.

Just FYI, I have an assortment of sized metal endpin stands that can be put on the bottom of the instrument to raise it up if one's sitting on a taller chair or stool, or standing.

The silly "pie pan" 1920s resonator plate is in the middle of the rear as a tiny tone deflector and also as a place to rest one's knee while plying this (the instrument sort of sits sideways between the legs when playing to simulate a "side-straddled" position like when one plays upright. I may yet find a bigger "deflector" that will improve tone as well.

As I said earlier, I really didn't like the huge (of a similar style) aluminum resonator that I had installed over the whole rear at one point. It was too heavy, bulky, and didn't seem to do anything at all for volume or projection. I guess at some point it's better just to push air!

Here you can see the simple hardware store fittings that raise the neck/dowel portion of the instrument off the top of the head. This configuration is oh-so stable vs. a regular banjo dowel design since the strength of the body is carried right through to the end of the strings.

Here's a quick shot in my dirty workshop to compare the size. My upright is a standard 3/4 size, so it's the same size as just about any other regular upright you'd see.

Ok, hope that didn't bore all of you! I know seeing the same thing twice may get old, but it's fun to talk about the little things that make big differences. Tinkering is the best...!

I'm now very happy with the instrument, though I need to find a supplier for flatwound, nylon-core 1/4 size upright or bass guitar strings (this is a 34" scale so those would work, too). I have a set of D'Addario steel core 1/4 size upright strings on it right now, but they just don't feel as nice or fast coming from a nylon/gut-strung upright. Hint, hint: if you know of any -- let me know!


mitch said...

I would love to hear this! And after hearing it, I have a feeling I would also like to know if you would ever build one of these to sell?

Antebellum Instruments said...

Hi Mitch, I'll record a clip for it so you can hear. It's like an upright minus a bit of sustain -- punchier. If you play up the neck doing any sort of jazz runs this can easily outperform a DB there.

And yes, I'd build one to sell -- I would have to look and see what's available as far as parts go to get you the best pricing, though.

Anonymous said...

hi jake,

you may try the nylon core strings that hannabach makes for their acoustic bass guitar (sounds better than most steel string acoustic bass guitars). the set for 30" scale is # 842 MT. but they offer strings for longer scales too.
or ask guadalupe strings (maybe the handcoloured set?).
a british gentleman playing bass for a ukulele duo called the flaming hemorrhoids of hell has built a similar instruments, will try to find a picture.
best wishes from resopal

Anonymous said...


I too would love to hear this, so hope you get a clip up. I've seen photos of old banjo-basses and mando-basses, but never heard either one played.

If you're going to keep trying out ideas along this line, i'd love to hear a fretted bass - I know the Gibson mando-basses had frets, but again I've only seen pictures I've never heard one.

chris said...

Is there a video for this on youtube? i'd love to hear it