Rattling Fretless A-string

[BeenDown139]

i have a 30-year old fretless 5-string essence (affectionately known not-disparingly as the 'cheap bass' at castle BeenDown) that has a persistant A-string buzz between the about 3rd and 7th positions whenever the neck or action gets a little out of whack.  in fact, whenever i start getting a transition from mwahh to ZZZZZ in hte A-string is when i know it's time to get out the bass tools and do some tweaking.  this A-string anomaly is what keeps me from having the low action on this bass that i enjoy with my other fretless.  this is my gigging fretless.  it's been getting worse lately.  current setup is very slight relief in the neck, strung with TI flats.  i've always wondered if there wasn't a wierd spot on the neck, but it doesn't look unusual there.  what i did notice when i was digging into this is that the slots in nut for the A and D strings look unusually deep.  i raised the nut about 1/32" after i took this shot.  it helped somewhat, gonna play it in and see where it goes from here.

my question is - do the slots for the A and D string look deep?  all my other basses have about half the string above the slot.  the problem with raising the nut (or the bridge for that matter) is that it affects the other strings as well, which may not be desireable.

any thoughts/suggestions would be welcome.

[sonicus]

Perhaps a small increment higher of a bridge adjustment on the low register side of the bridge as well ,for a possible improvement ? I once silver soldered an overly deep brass string nut slot on a non Alembic instrument. It was then possible to bring the height of that string to desired specifications .

[JimmyJ]

Action is trickier on a fretless, for sure.  I think you're right, the A and D may be a bit deep - at least compared to the G.  I would suggest maybe cutting down that G-string saddle slot so that you can raise that side of the bridge a bit.  Sonicus did it the hard way by adding material to a slot but I would do it the lazy way by taking material away from the others.    

Here are a couple pics of a 12" radius cardboard guide I once made when trying to get the nut slots right.  This would also work at the bridge.  And while the goal is to get the bottom of the strings to match the radius, since the string gauges also taper I figured checking the tops was close enough.  And it worked pretty good.

Jimmy J

[BeenDown139]

Here are a couple pics of a 12" radius cardboard guide I once made when trying to get the nut slots right.  This would also work at the bridge

this may sound like a stupid question, but...
are all alembic fingerboards 12" radius? 

raising the nut made a big difference.  it didn't really affect the action on hte other strings and the A-string's still got a little more mwahh  than the other strings.  but the buzzing's gone.   i'm gonna let it ride for a while to see if it's worth chasing further.  i don't want to do anything that i can't undo if i screw it up.

by way of contrast, here is the nut from my other fretless, AKA the A-bass. it's a shop night bass with a series II body.  this bass plays perfectly up, down and across the neck.  the string spacing's a little narrow for my liking but i let it slide.  i never really looked at the nut because i never really had to.  kinda like to hear the story behind this:

[Songdog]

Those nut slots are... capacious!

What do you know of the A-bass's history? Perhaps someone had Rotosound tapewounds (65 75 100 115) on it? Or set it up for BEAD?

[StephenR]

When the bass was made the nut slots would have been cut for the strings someone indicated they wanted to have on the bass when the build was finished. I would imagine that Alembic nut slots have more variation due to being essentially custom orders and builds. Production basses from one of the major manufacturers would all be the same based on what nut slot size  they thought would cover a wide range of string choices.

Sounds like you found a solution for now.... play on!

[BeenDown139]

...What do you know of the A-bass's history? Perhaps someone...

it's a shop night bass with a logo and serial number.  i got a partial build sheet from the serial number lookup.  i'd like to think the original owner/builder (i think i'm the 2nd owner not counting the shop i bought it from) was a bass player like me and built it fit his playing style and hands.  it sure plays nice.

When the bass was made the nut slots would have been cut for the strings someone indicated they wanted to have on the bass when the build was finished....

based on the way this nut looks i'd be inclined to guess it was one that was laying around, or an experiment or a rescue from the scrap bin.  however ya slice it, it works so i'm not touching it.

here's a video i posted earlier of me doing a playalong on the A-bass.  i'm mostly in hte left channel, bass in stereo mode, mic pointed between the speakers. i was originally looking for an unlined series 5-string with the trimmings.  since one never really popped up, i took a gamble on this one.  it has to be heard in person to really appreciate the tone this bass has.  the essence is a very nice bass but can't touch this one tone-wise.  it's got a B-string and it's my bar-hopper elsewise it woulda hit the auction block long ago.  the A-bass only leaves the house on special occasions.

[BeenDown139]

my cover band crashed but i may get picked up by a jazz band but it'll be a fretless only gig.  since the A-Bass doesn't leave the house, it's up to the cheap bass to get me the job.  which means i gotta deal with this A-string rattle once and for all.  i rummaged around in the shop, came up with some copper foil from an electronics project, folded it up to make about a 1/32" shim and put it in the slot under the A-string.
it raised the string just enough to kill the rattle.  the string sound now feels balanced from string to string.  kinda restored the radius, just enough that i can feel it a little.  so i'm gonna call it a win.  not touching the other slots.  can't make it permanent because the string sits right over the locking screw for the nut.  i don't change strings that often on this bass so it's the next owner's issue.