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psarkissian

Service Engineer Moderator
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Posts posted by psarkissian

  1. stevekc suggestion is a good place to start. He knows his stuff. One

    of five people in the Americas (north or south) I trust to do a mod on

    a JTV, ... without messing it up. Work on one of his Bigsby JTV-59's,...

    ... nice.

     

    If it's in the "on" position, chances are it's just an alignment thing.

    If the volume of tone control knobs are loose, then it's just a matter

    of pulling off the knobs, testing the knob excursion for each position

    is good, then tightening the nuts down.

     

    There is also a spacer fix for that. A Line 6 authorized service center

    could deal with that or get a knob with the in it. Being an authorized

    service center, they would check out all the other things as well, as they

    would have access to service info and service manuals.

     

    Both of the above mentioned are simple and straight forward.

     

    If the encoder is jammed underneath, the pick-guard would have to come

    and that is a bit more involved. There could be a couple of reasons for that,

    including a failed encoder.

     

     

    In any case, it should be looked at by someone who knows the product.

    At this point giving a ballpark idea would not be possible until a better idea is

    regarding the above mentioned possibilities. They are just too wide and varied.

     

    BTW, what's the serial number of the JTV-69?

  2. Not the come line, but years of experience with these products,

    and decades with other electronics, seeing most every way they fail. 

     

    I used to crew for Iron Butterfly (1975-79), if that gives you some

    idea how far back I go.

     

    Keep those connections tight, a loosy-goosy can give you a spike.

    And that's bad for the supply rail of the guitar.

     

    In the meantime, make some music and rock on gear fab.

    • Upvote 1
    • Downvote 1
  3. There are rubber inserts underneath the end caps.

    End caps are to keep from damaging the top and bottom.

    They also help minimize cabinet vibrations. It also acts to

    keep the cabinet acoustically isolated to minimize acoustical

    loading of the ground, floor or mounting surface being used.

     

    Do not remove the end caps. If you do and the rubber inserts

    get lost or damaged, acoustical problems can occur when you

    try to mount or position the speakers for performance. And those

    rubber inserts have to be re-installed correctly. If they are lost

    or damaged, I don't know how easy it will be to replace them.

    And they would have to be re-install by someone who knows

    this product from the inside-out.

     

    It will also mess with the overall EQ of the sound. The Modeling

    is designed for the acoustics of the speakers as is. Modifying that

    will change the EQ of you overall sound, and the sound artifacts

    that go with it.

     

    So, in a nutshell,... please don't do that. Please.

  4. -Check the "Input" and make sure you have the correct device selected.

     

    -Check the "Output", "Match Studio/ Direct" is a common setting.

     

    -Down arrow and check the sample rate to make certain it matches the

    sample rate of the DAW or sound-card you are using.

     

    -Check the sound device selector on your computer to be certain that is

    set correctly.

  5. Bottom line,... use the specified tubes. Yes RealZap, there are reasons 

    for that. I could get into a long dissertation on that, and a list of examples

    of what has come across our benches. The consequences are that these

    amps end up on our benches.

     

    -It has to do with characteristic curves of the tube specs.

    -The way Bogner designs the amp sections.

    -Spider Valve, Alchemist and the DT series have a digital section for processing,

    so these are basically hybrid amps.

    -Since these are hybrid amps, you can't get away with the same kind of tube

    swapping like we used to do back in the 1960's and 1970's.

    -You can't use the same bias on other tubes as you do with the EH's.

    -EH's go through more scrutiny.

     

    Consequences are red plating which damages tubes and surrounding circuitry,

    blown digital boards and other such failures. Bottom line,... use the specified tubes.

     

    And RealZap,... keep up the good work.

  6. -MIDI time outs, usually accompanied by a red blinking LED, typically a

    transmission error of some kind.

     

    -When you re-Flash, if the prompt asks if you want to save patches, click "No",

    because you don't want to save a set of patches with errors, if there are any. 

     

    -Trying to use an effects floor product as an update interface device, instead

    of the JTV Interface can cause connecting and handshake problems. Use the

    JTV interface.

     

    -General internet communications glitches that can occur.

    • Upvote 1
  7. The device under the knob is the same, so the Models will come

    up in the same order, in the same way.

     

    However, the stop points on either end are such, that the Model labels

    on the knob won't line-up perfectly with the select LED indicator (just tried

    it on one of my test fixtures). So, there may be some confusion which Model

    is engaged until you play it (or it come up on the display of your multi effects

    floor unit, if you have one).

     

    Aside from those caveats, should work fine.

  8. WXT has the cup on the bottom the WGC doesn't. Use the WXT if you have the

    amp with the the bear trap or clamp type retainers.

     

    WXT are good for amps with the spring retainers, since the base cup helps counter

    any pressure from the springs. With taller tubes, the spring pressure was enough to

    crack a tube during transport.

     

    5881 vs 6L6WGC (or WXT),....

    1) Bias won't be the same between them because,...

    2) the characteristic curves are slightly different, and so,...

    3) you can't get away with the same sort of swapping we used to get away with

    back in the 1960's and 1970's. This is a different beast.

     

    Be aware, it may work now,...  but later,... that's another thing.

    And how hard you run it,... that factors into it as well.

     

    12AX7B is fine, anything else is fancy, and unnecessary overkill, but it will work,

    it's th s small signal pre-amp stage.

  9. I tested it on a JTV-59 with Flash v2.00 and v2.21, it’s less apparent when using Flash v2.21 (the latest and current).

    It sounds like the effect is a quirk of filtering processes,…

     

    -The pick-ups are inductors with a magnet. Passive Filters- inductor, capacitor and resistor are passive components, and create a “first-order† passive resonant filter circuit.

     

    -In Model mode, the filter is built around a function block, and if there is an amp (real or virtual) involved, then it creates

    an active filter circuit. Since it is an active filter, it is automatically a “second order†filter.

     

    -Passive filters are smooth across the frequency response band. Neve uses this in their mixing consoles, it’s a smooth response, and then they send that output to an amplifier, allowing gain changes and still maintaining that smooth response.

     

    -Active filters have emphasis and de-emphasis just before the roll-off frequency point. Synthesizers use this by exaggerating the emphasis and de-emphasis to create undulating filter sweeps, by cascading “second order†filters into one another to create extreme filter sweeps.

     

    The Chebyshev response curve is the one that is the smoother of the active filters, is stable and easier to control, and keeps ripple and emphasis to a minimum,… which is why some of us like using them in audio circuits.

     

    It’s how some Wah-Wah's works,… volume/tone pot is tied into an active circuit making it an active filter, changing the cut-off point or the Q-factor (gain at the resonance point). The more orders of active filter, the more extreme the effect you can get out of it.

     

    Sounds like what capdoogie is experiencing is an ultralight version of active filtering in Model mode vs passive pick-ups. Like I said earlier, less apparent with Flash v2.21 program.

     

     

  10. Or,....

    Log a ticket, get an RMA, and send it here to Line 6. The tech here who

    does the old Variax guitars has a couple jack assemblies,... he can install

    one (and check other stuff too while he's in it). I just asked him about it.

     

    Modifying a JTV assembly to fit can be done, but it's also a can of worms

    if you're not an experienced tech or circuit person.

  11. Open a ticket, get an RMA and take it to your nearest authorized

    Line 6 service person. When you do take it in, take the guitar, cables

    and accessories and the HD500, so they can go through it all an

    "fine-tooth-comb-it" along the entire signal chain. They will have

    access to service data and info.

     

    BTW,... I'm acquainted with silverhead, he knows his stuff.

  12. Rewolf48,... yes. 

    Using a regular CAT5 cable, it can jiggle and wiggle, 

    and that can (and often does) bend and damage the 

    pins in the VDI jack (in older Variax and JTV). And that 

    can (and often does) damage or short out circuitry. 

     

    We see this all the time. We've been telling everyone

    about this since the days of the early Variax guitars, to 

    use the correct cable for the correct use. My lab mate 

    has dealt with early Variax from the start, and I've

    serviced hundreds (literally, so I've lost count) of JTV's

    from its beginnings. We've seen too many bent pins 

    in VDI jacks and too many shorted out boards,... 

    please, use the correct cable for the correct use.  

     

    Been doing this a long time (and I count in decades,

    not years). I have an old 300 Electric and four JTV's, 

    only VDI's on them and never had a problem. 

     

    I don't care what brand of VDI you use, just use a VDI cable. 

    It will save you a lot of grief later. And it will keep your 

    guitars from ending up on my bench. 

     

  13. That jack in the link is a JTV-69,... it won't fit physically and the electronic
    connections are not the same. Parts for JTV's are NOT interchangeable with
    the older Variax guitars (300/500/600/700).

    Do not use regular CAT5 cable,... use the VDI cable with the casing. Regular
    CAT5 will just wiggle around inside the jack, pins get bent and boards get
    shorted out. We wee this all too often here,... please, don't become a statistic.

    We've been warning people about that for years. And I think there may be
    something about that in the Pilot's Handbook. We see this on our tech benches
    all too often,.... use the proper VDI cable.

    Take the 500 Electric to an authorized Line 6 service center, or Line 6 itself.
    Don't try to open this can yourself,...  leave it to the pros.

     

     

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