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Which kind of replacement jacks for Trace SMX pedal?

Discussion in 'Effects [BG]' started by SwamiRob, Feb 12, 2017.


  1. I've got a dual band compressor that's been an absolute tank for the last few years I've owned it until recently. The output jack has been such a pain and the contacts keep getting loose, the thread that keeps the thing in place is knackered, and the whole thing is causing a lot of problems. So I'm gonna get some solid jacks to keep it in place, however the amount of options is a little overwhelming, and the thing that's most confusing is that some are labelled as "sleeve contact/front panel connection" although I can't see any viable difference between 2 of the Neutrik jacks, of which one says that it has the sleeve panel whatever it is listed as a feature and the other doesn't. Tried to look up the terms and had no joy.

    Here's the list of parts I was looking at by the way, was ideally after the ones without nuts so I can have the cool red ones but I'm sure I can live without if it complicates matters with matching the right kind of thread.

    PCB Mount

    Ta for any help
     
  2. boomertech

    boomertech Frank Appleton Supporting Member Commercial User

    Apr 8, 2009
    Syracuse, NY
    Designer/Owner of FEA Labs
    A picture of the jacks would really help with identifying the ones you need.

    -Frank
     
  3. Sorry didn't specify, they're stereo ones that other then not having gold contacts look exactly like these Neutrik NRJ6HH-AU . Cant ate any pictures at the moment but they have the same enclosure, thread length and have 6 pins. Was gonna go for summet with a longer thread ideally so the same thing didn't happen again
     
  4. boomertech

    boomertech Frank Appleton Supporting Member Commercial User

    Apr 8, 2009
    Syracuse, NY
    Designer/Owner of FEA Labs
    Sleeve contact is when they use two contacts on the sleeve portion of the plug instead of one... it allows for more types of jack wiring configurations. And it may have a better grounding contact.

    See the jack schematic in this PDF with a "sleeve contact":

    http://www.neutrik.com/zoolu-website/media/download/2842/Drawing+NRJ6HF-1

    You can see that both the S (sleeve) and G (ground) will be making contact when a plug is inserted. With the other style of jacks, the sleeve will only make contact with the one sleeve spring and open the contact with its associated "closed" pin.

    To be able to use a "sleeve contact" jack you would need the copper on the PCB to be configured for it if they are using the G and S pins for battery switching. But you can use a "sleeve contact" jack to replace a normal type... just connect the G and S pins together for a better ground connection.

    -Frank
     
  5. So correct me if I'm wrong - The 3 sets of pins in the jack will be closed or open, and dependent on that the pedal circuit can route straight through that input if needed when closed, or take signal from the jack if open. Then with the sleeve contact there is 3 signal paths that turn into 4 when something is plugged in, with
     
  6. the extra contact inside the jack barrel routing to what would otherwise be an inactive pin?

    No idea how the earthing works on this SMX however. Any chance you could help it out having made a version of it yourself? I was also toying with the idea of changing the crossover frequency to something lower, and possibly the overlap between the bands
     
  7. to drop off much quicker or if possible eradicate it completely. Not sure how feasible the latter would be.

    Apologies for the formatting, old phone being difficult again!
     
  8. boomertech

    boomertech Frank Appleton Supporting Member Commercial User

    Apr 8, 2009
    Syracuse, NY
    Designer/Owner of FEA Labs
    The jack schematics are drawn without a plug inserted so, it is pretty clear as what switched pins are connected without a plug inserted. The G and S pins are both connected to the sleeve of the plug when one is inserted, they do not make contact with each other when there is no plug.

    For a 'normal' type of jack there are three switched contacts for the tip, ring and sleeve springs. All three switched contact pins will be opened when a plug is inserted.

    My SMX comp design only has the same attack, release and x-over parameters as the TE SMX. The two circuit designs are completely different. IIRC, as the SMX is designed now, the two freq bands have an approx 3dB bump at 350Hz where they are mixed back together. If you change the x-over filters to have a greater overlap, the bump will increase.

    You could redesign the circuit as a two parallel full-band comps, but the effort to do so would be wasted IMHO. If you want a full-band comp, there are much better offerings today from other manufacturers.

    -Frank
     
  9. Cool, cheers for that, will probably play it safe and stick with the original but good to know the distinction.

    As for the modding I was just trying to get the crossover to a lower frequency. Wanna ideally just be compressing the real low stuff. Wanna save up for one of your dual band comps really, so i can set it really low and also compress it how i want too, then be able to have a very light hint on the top band.