pros and cons of stacked jazz knobs?

Discussion in 'Basses [BG]' started by kkaarrll, May 7, 2017.


  1. Grinderman

    Grinderman

    Dec 21, 2013
    I'm happy with my VTVT stacked knob setup. It did take some fiddling with setup though to get it right.

    1. I ditched the detente washers that engage the holes in the bottoms of the lower black tone knobs. Those things are useless and only make the tone adjustment sweeps bumpy and rough. They were replaced with the regular flat washers used with any other control pot.

    2. The top chrome volume knobs can drag or snag the lower black tone knobs. It's annoying as hell. The common fault is in the depth of the shaft holes cast or machined up into the knobs. The bore of the holes goes too deep or too high up into the knobs. It's such a simple thing. I have no idea why Fender or anyone else who might make these knobs has never recognized this simple flaw and adjusted their production tooling accordingly to solve it.

    I solved this for myself by making two equally short nubs or filler/spacers out of a maple dowel rod of the right diameter to be tightly press fitted up into the top of the shaft holes. With this mod the knobs bottom out on the volume pot shafts so they sit up slightly higher, but not so high as to be obvious or a problem. That eliminates the problem of the tone and the volume knobs dragging on each other so that they won't turn/adjust independently.

    With everything dialed in setup wise with wires, pots, cap, resistors and input jack tucked in neatly where they need to be in the shielded body cavity, along with those two changes above everything works smoothly and predictably. I have no problems with unfortunate interdependent interactions between the neck and bridge tone knobs or volume knobs.
     
    Last edited: Jul 22, 2021
  2. mojomike001

    mojomike001

    Mar 28, 2013
    South Florida
    Let’s be real. The stacked knobs look cool as hell, but the vvt is a better working system. That said, my stack knob ‘60 jazz clone is one of my favorite basses.
     
    Templar likes this.
  3. dylanjohnson

    dylanjohnson Supporting Member

    Jul 9, 2002
    Morro Bay, CA
    If you have a '60, the bass sounds so good dimed that you likely wont need to touch the tone knobs anyway.
     
  4. Templar

    Templar Supporting Member

    Is it really a design flaw, though? There are set screws to adjust knob heights so the bottom one won't drag on the washer or the body below, and to ensure that the top knob won't drag against the bottom knob. The deep bore in the vol knob can accommodate differences in pot shaft lengths, where/when applicable.
     
  5. Grinderman

    Grinderman

    Dec 21, 2013
    The central volume control shaft length on CTS 250K/500K concentric solid shaft pots Fender has used for 60 years and sell as spare parts are to a uniform specified length. The excess hole depth in the volume knob only introduces the possibility that the volume knob will sit too low on the solid shaft post, causing drag between volume knobs and tone knobs. As they are, the depth of the blind hole in top volume knobs serves no functional purpose. Set screws are fine for holding rotational position on the posts, not so much indexing fine vertical location. Where I come from, the depth of the blind hole in the top volume knob is a suboptimal design specification.

    The détente spring washers under the tone knobs are different matter. Those can be adjusted slightly by pre-bending them up or down more with pliers, besides the bottom black tone knobs can be adjusted up or down to affect how much pressure they bring down as they ride of those détente spring washers. The ride contact between the spring washer and the knob bottom aids the set screw hold vertical location. I don't doubt some may like them. I found I do not like what those washers do and I've seen others say the same. The design intent was nice but in practice they provide no useful haptic feedback to the user and feel crappy rough in use. To each their own. If someone likes what those washers do that's fine.
     
    Last edited: Jul 22, 2021
  6. Templar

    Templar Supporting Member

    The set screws work perfectly well for vertical settings on the shafts. Whenever people complain about the two knobs interfering with each other it's universally because of user error, the knobs were not set correctly or have come loose because the screws were not tightened correctly. Like all other control knobs fastened with a set screw, they need to be adjusted properly. It's so simple that an eight year old can grasp the maneuver. Still, being able to operate a little allen wrench or a tiny screw driver is a requisite skill set. Wow...such a hassle.
     
    dabbler likes this.
  7. Grinderman

    Grinderman

    Dec 21, 2013
    Eight year old argument noted. Besides VTVT bass guitars based on the 1960 Fender design, there are vanishingly few, if any, other standard guitar or bass guitar control knob configurations that exist that involve a set screw to hold an up or down location to prevent interference or work properly.

    Make the blind hole only as deep as it needs to be, no further setup adjustment (machining setup, assembly line and future maintenance) needed. Done.
     
    Last edited: Jul 22, 2021
  8. Templar

    Templar Supporting Member

    Someone still has to work the set screws, regardless. Better to have some leeway for a "universal" fit for any brand of pot with any length of shaft, no? It's only logical that that was the reasoning behind the deep bore hole in the first place. And why no one has come up with a "better" design, as if being able to adjust settings to taste or function is somehow not good. Adjustability is a good thing, not a bad thing.

    If someone wants to stick dowels in their knobs to avoid having to properly adjust their knob heights, that's their business. The rest of the world may not view this as a "problem". Just sayin'...
     
  9. Grinderman

    Grinderman

    Dec 21, 2013

    The solid central volume control shaft on the pots all project 0.5", minimum, above the outer hollow or sleeved tone control shaft. The blind hole depth up into Fender's volume knobs is also 0.5".

    Speaking of thinking logically, leeway or adjustability to solve what problem?

    If, there were pot shafts out of tolerance toward the long side, e.g. 0.53", the depth of the blind hole in the knob, whether it's 0.44", 0.5", or 0.52", makes no difference; no additional interference.

    If there were a lot of pots with shafts short of tolerance, the 0.5" deep blind hole in the knob would provide "leeway" would serve no function or purpose either.

    Conclusion; there's no reason why that blind hole needs to be 0.5" deep and there's no reason why .44" deep would not be better.
     
    Last edited: Jul 22, 2021
  10. Grinderman

    Grinderman

    Dec 21, 2013
    Other comments in this thread of discussion on topic indicate the entire rest of the world does not agree that this as not a problem, besides me. Otherwise, I'd never mention it--logically.
     
    Last edited: Jul 22, 2021
  11. Templar

    Templar Supporting Member

    I guess people have different notions of what constitutes a "problem". One guy said he adjusts his knobs once a year. Another said his worked fine for the first 25 years before they needed adjusting.

    Within this discussion of pros and cons of stacked knobs, the main issue for the detractors seems to be the effectiveness of (or the lack of) the stacked system, or the lack of visible reference points, or that it's too fiddly, or that the output signal is reduced. All valid concerns, of course.

    As an aside; Funny how no one gripes about the knobs on a P bass, which are also fastened with a set screw. And if not adjusted properly for height can drag against what is below them. Why no complaints? Because it's well understood that a simple, quick adjustment solves the so-called "problem". Same principle applies to both types of knob arrays. As with most things, there are always outliers who see things differently than the majority of us. And that's a good thing, too. Cheers.
     
    dabbler likes this.
  12. Grinderman

    Grinderman

    Dec 21, 2013
    Could it be because they're not stacked and they never drag when they're simply fully seated down on their respective pot shafts? :rolleyes:

    It certainly can't or never happens with the T and V knobs on my PB-63. It's never happened on any of my other Fenders and one Washburn I've owned/used over the last 35+ years; including Fender P, PJ, '65 VVT Jazz, Bass VI, and Stratocaster. All that despite working on all of them myself, including fixing or reaffixing control knobs on all of them at some point.

    For whatever reason, you characterize as griping what I wrote with the intent to share information. Meanwhile you bring nothing useful to the topic at all. Perhaps you're just bored and looking to waste time. :facepalm:

    There's another active thread of discussion on this forum right now titled "Sales of Precision vs. Jazz basses: Which sells more?" Here's why I don't say anything about that; because I don't care and I've got better things to do with my time.

    Next.

    Have a nice day.
     
    Last edited: Jul 22, 2021
  13. Grinderman

    Grinderman

    Dec 21, 2013
    Dammit! Every time I turn the volume knob on my P the whole bass spins along with it like I'm ZZ Top. :roflmao:
     
  14. Templar

    Templar Supporting Member

    There's information and then there's misinformation, which is what you've introduced to the thread, for some reason. Maybe because some people just like to make things up, whatever. No one needs to re-engineer their control knobs, or insert wooden dowels into them in order to have them fit properly. After all, the set screw is there for a reason, and it's worked brilliantly for decades. This shouldn't be news to anyone, but if it helps dispel yet another guitar myth, then maybe it's been "useful" for someone.

    I have to admit, you're the first person I've come across that has gone to such lengths to correct what they perceive to be a design flaw in a control knob. It's comical that anyone would bother with all that, but to each their own. Cheerios.
     
    FRoss6788 likes this.
  15. Templar

    Templar Supporting Member

    Right? Agree 100%. A VVT setup is easier to use, is cheaper to produce, and is flat out louder than the stacked setup (which was kinda important back in '62 when Fender dumped the stacks). And yet, as a former owner of an all original '61 Jazz, I have to admit there is definitely some intangible allure there. Confirmation bias?...maybe. Despite the reduced signal output, I loved it enough at the time to draw a schematic of the circuit. Thought it might come in handy for future a DIY build (which never happened).
     
  16. Grinderman

    Grinderman

    Dec 21, 2013
    You're entitled to your opinions. What misinformation?
     
    Last edited: Jul 22, 2021
  17. Templar

    Templar Supporting Member

    Your "characterization" (to use your word) that the bore hole in the stacked vol knob is a design flaw serious enough to be considered a "problem". It's really not, the proof is that no one over decades has bothered to "correct" the design. I believe you've said as much yourself earlier, which would seem to contradict your flaw/problem assertion. No?
     
  18. Grinderman

    Grinderman

    Dec 21, 2013
    I described what I view to be the problem. I never used word "serious" to describe the flaw, that I consider to be a problem. "Serious" was your word. I described it as suboptimal and a simple flaw with a simple solution. I've stated the relevant dimensions of the parts involved, including the blind hole depth in the volume knob.

    Decades of reproducing something doesn't prove anything other than it's been produced the same way for decades.

    What misinformation are you referring to?
     
  19. Templar

    Templar Supporting Member

    Uh, sure sounds like you think it's pretty "serious". Were you really "annoyed" enough to go to such lengths to fix a "problem"?

     
  20. Grinderman

    Grinderman

    Dec 21, 2013
    That's not misinformation. That's my informed opinion which I'm entitled to as much as you are. Whether you agree is irrelevant to me and your claim of misinformation.

    Feel free to try again, or not. If you don't, then we'll know that it was you who was producing misinformation.
     
    Last edited: Jul 22, 2021
  21. Primary

    Primary TB Assistant

    Here are some related products that TB members are talking about. Clicking on a product will take you to TB’s partner, Primary, where you can find links to TB discussions about these products.

     
    Jul 30, 2021

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