2/21/2014

c.2014 Antebellum "Precision" Banjo Bass




Update: I've recorded a new soundclip that's a bit more accurate tone-wise. Now, back to the original post!

Well, here's "part one" of my newest banjo bass duo: this is the fretted, bass guitar style instrument. I'm calling it a "Precision Banjo Bass" for lack of a better moniker. This instrument has taken a lot of thought to build just right, but I'm super, super pleased with the results. It achieved all of the goals I wanted: stability, volume and punch, easy of playability, light weight (it's only 6lbs 5oz!), and ergonomically it's a very comfortable instrument to play for long periods. It also looks pretty wild.



Update: Since finishing this I've put about 8 hours of play into it as I write this, 2 of which were "on stage" and 1 in a jam. It's simply a blast to play and the crowd response from audience and other musicians is pure joy. One fella came up to me and said, "I love the way your bass looks like a banjo" -- he thought I was plugged-in because there was an amp for our microphones behind me -- and when I told him it was all acoustic and it was a banjo bass, the look of surprise that ran across his face was priceless.

Compared to the upright/double bass version of this same idea that I'm working on at the moment, this "Precision" banjo bass uses more off-the-shelf pieces: namely that Warmoth showcase "Tele" style bass neck with the gorgeous birdseye maple speckled throughout.

The rim is also a pre-tensioned, off-the-shelf 18" Remo "tar" which happens to have their "Skyndeep" goatskin-looking synthetic head and a curious textured finish all around the outside of the rim which further gives the instrument a stand-out look.


The Warmoth neck is nice quality of course -- and a straight "string tree" plus Hipshot tuners give it a snazzy and simple look. The 1 1/2" width (my preference) nut is GraphTech stuff which I used because it'll be easy and slippery for the strings I'm using...

...which are Savarez "classical bass guitar" strings with a nylon core. They're like oversized classical guitar strings. This was a necessary part of this project because #1 they sound warmer than conventional steel electric bass strings and #2 they put less tension on the head than steel strings (a plus for banjo-style instruments) and #3 they cost $15 a pop rather than $100 a pop for 1/4 size double bass strings which would be my first choice. Also, being roundwound, they have more of a "bass guitar" feel and tonality -- more piano than bell-bottomed upright tone.


The frets are giant... which feel perfect with the nylon strings. Note that action is jacked up to about 3/32" at the 12th on the treble side and 1/8" on the bass side. The nylon cores wobble more than steel cores so, just like on a double bass, action needs to be higher than on an electric bass so you can dig into it and avoid fret buzz. Still, because of the nylon strings, the difference is negated as the tension is so light comparatively.


The aluminum trim "waist" is an absolutely necessary part of the design. My last fretted banjo bass was the same size but suffered an awkward feel in the lap due to the rim "slipping" past the leg or pushing the neck too far away from the hands. This "waist frame" is roughly the size of an electric bass and balances the whole instrument on your knee just right. I can't stress enough how important this addition was to making this a viable instrument.


The ribbed aluminum actually looks pretty cool in person. It's very "modern" but, in that strange 50s way, reminds me of old Harmony aluminum-trim guitars. The vintage P-bass headstock shape adds to that, too.


Note also the strap button on the bass-side "wing" which lets you balance the bass nicely off the shoulder. The "wing" like on an electric bass also lets you snug the instrument into your chest so it's good and stable.


I made a mandolin-style rosewood adjustable bridge for the instrument. I've tried a number of different materials -- even softwoods (like brace stock) -- but a lightweight rosewood bridge with wide wings is what worked best. It definitely helps deepen the tone. For extra power, though, using something like spruce brace stock gave a little more cut.

The tailpiece is simply double bass tailpiece cable attached to a rosewood block. It's necessary to use a wood block to secure these nylon bass guitar strings as you don't want the core to get cut over sharp metal edges.


There's a strap button near the middle of the rim's side which approximates the position of an electric bass bottom strap button.


The rim is only 3" deep which means that this feels (in the lap) like playing a tight-waisted mini-jumbo or archtop guitar.


Note: above picture is from a slightly older set of pics in grey weather -- I realized I hadn't snagged this "full back" shotwhen I took the second set!


Here you can see my giant maple "dowel" design. Unlike a regular banjo, the rim itself actually takes zero compression tension from the strings. All of the tension is leveraged over this giant quartersawn (neck stock) maple "body" and the neck that is bolted to it. This is the only way I can get away with using a pre-tensioned Remo frame drum -- otherwise the drum's rim would be under too much tension and the instrument wouldn't be stable. The frame drum design also eliminates tons of banjo hardware weight that would otherwise be necessary.

Note how big the "dowel" is, though -- it's acting here like the solid body of an electric bass.


The lightweight, US-made Hipshot tuners are a nice addition and keep the look elegant. I added a button here for those who want to hang this from the neck. I always prefer "body hanging" myself as there's no chance of neck wobble from leaning/pulling against the instrument, though. Still, the Warmoth necks are heavy-duty and mucho-reinforced and I noticed no movement when I had the strap up here.


I used transparent "gel varnish" which is actually a wipe-on/off poly finish that you can apply in thin coats and then buff out after drying. I love this stuff as it feels almost like playing bare wood and is certainly nice and water-resistant.


Here's a closeup of those hardware-store fittings. The little gadget at the bottom tensions the dowel to the rim just to keep it in place. I could actually string this up without needing an attachment piece here because of the design but isn't it nicer to have the peace of mind?



Neck angle can easily be adjusted during string changes by drilling holes up or down the end of the dowel to mount the "endbolt." The cutout in the rim is standard for use in frame drumming.



A simple strap button holds that plastic-encased steel-cable tailpiece wire in place.

2 comments:

Anonymous said...

Pretty cool

Andreas said...

have you sold it yet?