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Posts posted by MiroslavKloud

  1. I will try to summarize the information about my guitar.

    Hopefully it will be at least somewhat comprehensible.


    1) The strings E6 and A5 produce a parasitic frequencies. String E6 - approximately 1.7kHz, string A5 - approximately 1.9kHz (in addition there are harmonic frequencies).

    Frequencies were determined by measuring of the direct signal from the piezo (electronics disconnected), audible they are also at unconnected guitar (unplugged). On the string A5 is audible also through magnetic pickup.


    2) While using the modeling - the problem is only with the string E6.


    3) The piezo sensor E6 was replaced - no improvement.


    4) The complete bridge was replaced - no improvement.


    5) I swap the wires from the E6 and A5 piezos into the circuit board.

          - The string E6 is OK

          - The problem is now on the string A5


    6) The electronics was replaced - no improvement.


    Options to solve the problem:


       - adjustment of the firmware - weaken the parasitic frequency on strings E6 (on the string A5 this works good)




       - find a reliable way to reduce mechanical cause (at least for strings E6)


    The most difficult task:

    convince Line6.

  2. "the source is not electronic, ... it's mechanical" - I say the same thing had long. But this is a normal phenomenon - the most strong on the string A5.

    "The electronics May amplify the problem" - yes, on the string E6 is this problem. On the string A5 the electronics works properly.


    DSP - frequency response (electronics frequency response)  - is not 100% objective.

    Directly from the piezo - is 99% objective - direct connection piezo-HD500 (3.5MOhm)

    Audio output from guitar - is 100% objective.


    You did not answer the question:

    Why there is no problem with the string A5?

  3. "... is audible even when the guitar is unconnected"---

    If it's doing that when it's unconnected, then the comment earlier about it

    not being electronic or Firmware, means that it's mechanical in nature.


    The electronics only put out what is inputted into it.



    #252  - Is it absolutely incomprehensible?


    And this?


  4. I think I had things a little confused until I wrote it out. Does this look right?


    Ex. 1: Piez.....

    If I understand the question correctly - my situation is corresponds to Ex.2.
    The circuit board was replaced at a service center.
    Piezos and also the entire bridge exchanged previously in another service center.
    Solutions in the firmware - reducing the frequency of around 1.7kHz (so as the input for A5)
    Various versions of the firmware might be the solution. Or automatic detection of problem frequencies. Or allow individual settings in Workbench.

  5. It's not firmware, its mechanical. File the Low E piezo casing and you can get on with enjoying your guitar.

    Why the string A5 is fine, even though has greater mechanical problem than the string E6? Why if is exchange wires from piezo A5-E6 is E6 fine and the problem is on the A5?
    Please look the images in my previous post.
    However, I agree that if eliminate mechanical cause, there is no need to deal with the firmware.
    The gap between the string and the casing is big on my guitar.

  6. I concur.  That noise is definitely mechanical in origin.  Either the string is slapping vertically against the transducer or the entire transducer is slapping against the bridge casting. 

    The emergence of this vibration is a normal. I found that the same thing is going on my other guitars - Fender USA Stratocaster and Aria Pro II (superstrat).
    Various guitars and various strings is however different - frequency / volume. Maybe because some Variax with one firmware work well, others badly.
    More detailed explanation is here:
    http://line6.com/support/topic/6764-do-you-have-the-same-problem-with-6th-string/?p=112445 - Post # 237 - it is a copy of message for the service center.



    • Upvote 1

  7. Hi, 

    I already wrote (in more detail) above: the problem has a mechanical cause. It's a sort of vibration string / bridge, on which the magnetic pickup reacts minimally. The piezo but is very sensitive to this. This oscillation is normal, but vary on different guitars and different strings.

    When using the modeling, it is necessary to remove these frequencies - filter.

    On a string A5 exist the same phenomenon (even more pronounced), yet working normally.

  8. My description for service center:       (guitar returned unrepaired)


    E6 string (if using modeling and play with palm muting technique) produces a sharp, metallic sound.

    It is most noticeable on the empty string (E tone) - hi gain sound - model  SPANK (Stratocaster) - bridge pickup.

    The same disturbing tone is also reflected when tapping anyplace on the guitar, on the bridge, or if a finger slides on the string. Through a magnetic pickups is sound E6 fine.


    My findings:

    This disturbing frequency have a mechanical cause.  The same problem is also on the string A5 - there is even stronger - partly reacts also with a magnetic sensor. But with modeling is the string A5 fine.


    I suppose:

    Normally a string vibrates vertically (radially), on it readily responds a magnetic pickups.

    At the same time but the string A5 and E6 produces vibrations which spreads horizontally (axially) - the magnetic pickup on it almost unresponsive,

    but piezo sensor is very sensitive to them.

    The emergence of these oscillations is not unusual to me, i am noticing the same thing on a others guitars.


    I tried:

    1. In the connector on DSP I changed wires from the piezo sensors E6 and A5. The string E6 then was fine and the problem was on the string A5.


    2. I measured output from the guitar through a frequency analizer (screenshots are on the CD-ROM): At the string E6 is a significant peak between 1.6 - 1.7kHz.


    3. Similarly I measured signals directly from the piezo (for this I used a Line 6 POD HD500 with input impedance set at 3.5 MOhm) - DSP unconnected.

    - On the string E6 they are a peaks around 1.6-1.7KHz, 3.4KHz and 5KHz. 

    - On the string A5 they are the peaks - 1.9KHz, 3.8KHz and 5.6KHz.


    4. I used a noise fed to the inputs on the DSP through a decoupling capacitor (on the inputs is DC voltage), and I measured the frequency response. Level of the applied signal was a little lower, than is the output signal level from the piezo.

    This measurement I do not find be 100% objective, I do not know how the DSP evaluates the input signal - with a noise maybe "does not know what to do."


    However, from the measurements is obvious, that the interfering frequencies is on the string A5 filtered out, but on the string E6 not.

    I am confident that the error is in the firmware.



    Sorry for the bad English.

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