Fretless 4001: intonation/setup issue, need help

Setup, repair and restoration of Rickenbacker Instruments

Moderator: jingle_jangle

Re: Fretless 4001: intonation/setup issue, need help

Postby (Nel Nobody) » Mon Mar 20, 2017 4:24 am

jps wrote:Um, use your ears! :wink:


Which part are you referring to? Do you mean the second one, about "reverse-engineering" the problem, with the pictures?
As I said, the finger positions shown in the pictures give me the correct pitch for the note assigned to the that fret.

I'm merely suggesting that the intonation is incorrect this way, since according to descriptions given to me so far of what constitutes correct fretting technique, these positions should be wrong. Unless the E string really does need that much space to separate from the fretboard, which is why I ask you, since I'm not able to tell (neither by sight nor by touch).
If the intonation is indeed incorrect, then we're getting back to the original problem, since I would have to screw the saddle onto the backside of the saddle mount if I wanted to adjust the correct pitch further towards the fretlines than shown in the pictures.

Sorry for being a difficult customer, but I'm a bit confused here. And still unsure whether or not this quirk means I'm doing something wrong elsewhere with the setup of my bass that might damage it in the long run.
(Nel Nobody)
New member
 
Posts: 15
Joined: Thu Mar 09, 2017 1:30 pm

Re: Fretless 4001: intonation/setup issue, need help

Postby (jps) » Mon Mar 20, 2017 8:31 am

This is why most prefer unlined fingerboards for a fretless instrument. Lines are sometimes a useful guide but in the end, when playing a fretless instrument, listening for the correct pitch is the most important tool. Upright basses, and the great majority of fretless acoustic instruments, have a pretty rudimentary bridge for making intonation adjustments; people just learn where to place their fingers through listening and practice with their instruments. That is what I meant by using your ears.Don't depend of the visual guide of those lines on the fingerboard; they just get you close to where you want to be. Even with the lines you will need to adjust your position due to those soft, mushy, pliable things on the end of your "fretting" hand. :wink:
(Insert famous quote here)
User avatar
(jps)
RRF Consultant
 
Posts: 35937
Joined: Wed Feb 12, 2003 7:00 am
Location: Not of this Earth

Re: Fretless 4001: intonation/setup issue, need help

Postby (antipodean) » Tue Mar 21, 2017 3:06 am

I've been mulling this over and I'm very confused - it looks like the bass is perfectly in tune at the octave position, and is by all accounts in tune with the open string, but is sharp in between (hence the need to finger the notes well behind the lines). Given the size of the error up the neck, I would expect the open string to be quite sharp...

I suspect a string or nut issue.... how high is the string sitting in the nut? If it is a little high (or worse), fingered notes near the nut will pull sharp, with the error reducing as you play towards the bridge. Could this be the issue?
"I don't want to sound incredulous but I can't believe it" Rex Mossop
User avatar
(antipodean)
Senior Member
 
Posts: 3181
Joined: Wed Jan 09, 2008 2:27 am
Location: Sydney's North

Re: Fretless 4001: intonation/setup issue, need help

Postby (Nel Nobody) » Tue Mar 21, 2017 5:20 pm

jps wrote:This is why most prefer unlined fingerboards for a fretless instrument. Lines are sometimes a useful guide but in the end, when playing a fretless instrument, listening for the correct pitch is the most important tool. Upright basses, and the great majority of fretless acoustic instruments, have a pretty rudimentary bridge for making intonation adjustments; people just learn where to place their fingers through listening and practice with their instruments. That is what I meant by using your ears.Don't depend of the visual guide of those lines on the fingerboard; they just get you close to where you want to be. Even with the lines you will need to adjust your position due to those soft, mushy, pliable things on the end of your "fretting" hand. :wink:


Ah, I see! Thank you for clarifying!
I can agree to that, insofar that I don't plan to spend all of my bass playing life with my eyes locked on the fretboard. So, fretlines or not, I'll have to get the ear for it at some point, or at least muscle memory in my fretting hand.

antipodean wrote:I've been mulling this over and I'm very confused - it looks like the bass is perfectly in tune at the octave position, and is by all accounts in tune with the open string, but is sharp in between (hence the need to finger the notes well behind the lines). Given the size of the error up the neck, I would expect the open string to be quite sharp...

I suspect a string or nut issue.... how high is the string sitting in the nut? If it is a little high (or worse), fingered notes near the nut will pull sharp, with the error reducing as you play towards the bridge. Could this be the issue?


I see what you mean. Mind, I tried my best to get good pictures, but I think the positions might look a bit inconsistent from picture to picture due to angle, or because I "waggled" my finger slightly to correct a few cents this or that way. My generally impression was that the relative position for the correct pitch of each note lied roughly on the tail-wards edge of the triangular inlays, octave fret included. Here's a new picture of the latter:
Fretting_07.png

But there might indeed be a discrepancy, as you say. Whether it's caused by the nut, though, I can't tell. I've taken a look at it, and everything seems normals. The E string sits in its notch quite snuggly, roughly up to half it's diameter. Right at the exit onto the fretboard, the action is about 2 mm. Here are some pictures, maybe it'll help us figure out if there's something off.
Nut_02.png
Nut_01.png


In the meantime, thank you all very much for all the help so far! I just hope we're not chasing after a mistake that doesn't exist.
Maybe the frets were simply badly placed. If that's the case, it would explain why one of the previous owner had them removed. Why they would have filled in the bad spots in such a visible manner afterwards, rather than try and hide them, though... hm.
(Nel Nobody)
New member
 
Posts: 15
Joined: Thu Mar 09, 2017 1:30 pm

Re: Fretless 4001: intonation/setup issue, need help

Postby (jps) » Tue Mar 21, 2017 8:21 pm

Nel Nobody wrote:...Right at the exit onto the fretboard, the action is about 2 mm...

That pretty high, too high for me. Are those new strings?
(Insert famous quote here)
User avatar
(jps)
RRF Consultant
 
Posts: 35937
Joined: Wed Feb 12, 2003 7:00 am
Location: Not of this Earth

Re: Fretless 4001: intonation/setup issue, need help

Postby (antipodean) » Tue Mar 21, 2017 9:06 pm

Lightbulb moment!!!!! :idea:

With a fretted bass, the note reference point is at the top of the fret, which is around 1mm off the fingerboard. When you remove the frets from a bass, you drop the reference point down to the board. Assuming the nut slots have not been changed, this will result in the notes being sharp at the lines where the frets once were, as the strings are moving an extra mm down, whilst their anchor point at the nut remains unchanged, increasing string tension and thus raising pitch. If my theory is correct, the nut slots should be cut much lower on a fretless bass (the "action" at the nut lower) than on a fretted bass. Checking my fretless Warwick, this is indeed the case, with the strings being less than 1mm from the board at the nut, whilst my fretted 4001 has a similar 2mm string clearance at the nut to your bass.

Obviously, the height of the bridge plays a minor role - but this has probably been dialed in already via the height adjustment screws. A small adjustment at the nut should bring things into line. You my want to get a good tech or luthier to do this.

Edit : I see Jeff has made the same point in just one line, but I hope the wordy explanation helps.... :mrgreen:
"I don't want to sound incredulous but I can't believe it" Rex Mossop
User avatar
(antipodean)
Senior Member
 
Posts: 3181
Joined: Wed Jan 09, 2008 2:27 am
Location: Sydney's North

Re: Fretless 4001: intonation/setup issue, need help

Postby (jps) » Tue Mar 21, 2017 9:44 pm

:mrgreen:
(Insert famous quote here)
User avatar
(jps)
RRF Consultant
 
Posts: 35937
Joined: Wed Feb 12, 2003 7:00 am
Location: Not of this Earth

Re: Fretless 4001: intonation/setup issue, need help

Postby (Nel Nobody) » Wed Mar 22, 2017 5:00 pm

Ah ha! That explanation makes sense! And I certainly don't mind the wordiness, ha ha! Gives me more stuff to fill the holes in my brain with.
I quite certainly don't mind engaging in some DIY, but from what I understand this probably is a bit too sensitive to handle myself. I guess I'll call my local store and ask if they can recommend me someone to take care of this.

Thank you very much for your patience and your help, both of you!
I'll still keep an eye on the thread, but if there's nothing else until then, I'll at least make a post to let you know if everything works out.
(Nel Nobody)
New member
 
Posts: 15
Joined: Thu Mar 09, 2017 1:30 pm

Re: Fretless 4001: intonation/setup issue, need help

Postby (jps) » Wed Mar 22, 2017 11:45 pm

You can file the nut slots down yourself. It is not hard to do, you just have to take it slow and easy so as not to go too far with it. Real ($$) nut files would be best but a couple different sized rat tail files can do the job just fine, with care. The most important thing to watch for is that the bottom of the slots stay are slightly angled downwards towards the headstock to ensure the witness point of the slot is at the fingerboard edge of the nut.
(Insert famous quote here)
User avatar
(jps)
RRF Consultant
 
Posts: 35937
Joined: Wed Feb 12, 2003 7:00 am
Location: Not of this Earth

Re: Fretless 4001: intonation/setup issue, need help

Postby (Nel Nobody) » Thu Mar 23, 2017 2:44 pm

I see. Hm.
Thank you for the info, I'll see whether I feel confident enough to do it. I mean, I certainly have tools that should do the trick.

However, what do I have to pay attention to in order to know whether I'm low enough? From guides and tips on the subject that I managed to find elsewhere, the most common method seems to be to put the string back in the slot, tune it, then press down on the third fret and look at the first fret: if there is just enough space to slip something like a credit card between the fretboard and the string, it's good. Is that trick also appropriate to use here? (Using proper fretting technique, with the finger pushing directly on or just nut-wards of the fretline of the third fret?)

I'm worried whether it would be. On one hand, it might again be something exclusive to fretted basses; on the other, I've read so much about Rickenbacker necks being "weird" due to being best set up entirely flat, I'm unsure whether it would affect the result of the test.

On the subject of the witness point, I understand what you mean. But I suppose the best would be that the slot were parallel to the angle of entry of the string, "hugging" it as tightly as possible all the way through the nut, no?
I ask because I took a closer look at the nut, and it looks like some of the strings actually "float" in their slots on the headstock side. (Most likely due to the nut having already been tampered with by a previous owner - there are some signs of filing and cutting in and around the slots.)
(Nel Nobody)
New member
 
Posts: 15
Joined: Thu Mar 09, 2017 1:30 pm

Re: Fretless 4001: intonation/setup issue, need help

Postby (aceonbass) » Thu Mar 23, 2017 2:50 pm

While it might be possible to work nut slots lower with a small rat tail file, properly gauged nut files that are round on the bottom are the only way to get a precisely shaped slot with a semicircular shaped bottom that fits a string properly. If you go too deep, you'll need to build up the slot with super glue and plastic shavings (or metal filings) to start again.
User avatar
(aceonbass)
Veteran RRF member
 
Posts: 6512
Joined: Tue Jul 09, 2002 6:00 am
Location: Parkville, Missouri

Re: Fretless 4001: intonation/setup issue, need help

Postby (Nel Nobody) » Fri Mar 24, 2017 5:23 pm

Understood! Thank you for your input. I've looked up what some proper files would cost, and while they are indeed expensive, I'm pretty sure that they're about the same if not cheaper than having the job done by a tech or luthier. That is, if we agree on a specific test by which I could determine whether the slots are deep enough.

Before we go there, though, let's backtrack a bit. After spotting the previously mentioned signs of work that likely had been done on the nut, I've taken a closer at it. What I found doesn't look anything like what you've described as properly done slotting, at least not to me. I'll let you judge, since I might just engage in a further display of my ignorance.
(Just in case they're not evident enough in the pictures: there are cuts in the center of the E, A and D slots; the cut in the A slot being somewhat less deep than the other two. The shadows on the fretboard show them more clearly.)

Nut_03.png
Nut_04.png
Nut_05.png
(Nel Nobody)
New member
 
Posts: 15
Joined: Thu Mar 09, 2017 1:30 pm

Re: Fretless 4001: intonation/setup issue, need help

Postby (aceonbass) » Fri Mar 24, 2017 6:29 pm

The right tool for the job, I always say....and whomever made those slots didn't use the right tool. The slots in this nut were originally located, then cut with a saw blade, followed by a rat tail file. Unfortunately, this was pretty common place at RIC for a number of years at least until the current laser cut nuts came into production.
User avatar
(aceonbass)
Veteran RRF member
 
Posts: 6512
Joined: Tue Jul 09, 2002 6:00 am
Location: Parkville, Missouri

Re: Fretless 4001: intonation/setup issue, need help

Postby (Nel Nobody) » Sat Mar 25, 2017 8:31 am

I see. Thanks for clearing that up.
So, what should I do? Fill up the sawblade cuts and pad the bottom of the slots in the manner you mentioned (super glue + plastic/metal filings), get a decent set of files and height gauges and give them a proper shape? Or are they too damaged for that?

On a sidenote, I tried to remeasure the string heights more accurately, since after looking at the nut so closely, my previous measurement of 2mm seemed incorrect (Sorry about that, I think I angled the camera while I took the shot). Apparently the heights are closer to this:
Nut_06.png
(from left to right)
E string: 1.1 mm
A string: 1.2 mm
D string: 1.0 mm
G string: 0.8 mm
(Nel Nobody)
New member
 
Posts: 15
Joined: Thu Mar 09, 2017 1:30 pm

Re: Fretless 4001: intonation/setup issue, need help

Postby (Nel Nobody) » Mon Mar 27, 2017 2:17 pm

Sorry for the double-post, I just wanted to mention an alternative I saw after having a look around:

I could remove the nut wholesale, and replace it with a pre-slotted one, where I would just have to file at the bottom in order to adjust the height.
That'd be much cheaper than the files, but only assuming that the pre-slotting was done properly. Has anyone here had previous experiences with those?
(Nel Nobody)
New member
 
Posts: 15
Joined: Thu Mar 09, 2017 1:30 pm

PreviousNext

Return to "Vibrola" Rickenbacker Technical Forum: By Paul Wilczynski

Who is online

Users browsing this forum: No registered users and 2 guests