3 portable on-ears: Koss PortaPro, Senn PX100-II, AKG K403

Discussion in 'Audio Science' started by Biodegraded, Oct 28, 2017.

  1. Tromick

    Tromick Rando

    May 8, 2020
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    Istanbul, Turkey
  2. Biodegraded

    Biodegraded Friend

    May 28, 2017
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    Vancouver BC
    Headband alternatives for KSC75

    For something more sturdy than the headband of the Parts Express pair, the Koss KPH7 remains about the cheapest and is an easy hack (described earlier); but it might not be great for larger heads and requires removal of the cable-termination covers on the backs of the drivers, leading to the cable connections being even weaker than stock.

    If you really want the 75 drivers, are prepared to spend as much or more on a headband for them, and are into the PortaPro aesthetic, this one looks like the ticket (I wouldn't be surprised if it's made in the same factory as the real ones):


    If you want a more traditional headband that's stronger than the KPH7 one but costs a bit more and you don't mind a bit of DIY, you can use the one from the JVC HAS160 Flats (trust me, the band is the best thing about these):


    This is a pretty nice unit, with a stainless-steel band/spring, arms that allow the earpieces to rotate flat, and enough room to accommodate the Yaxi pads - but it does require a bit of time and effort and destruction of the original KSC75 clips to fit them onto it:


    Here's the procedure...

    First, arm disassembly: remove the Phillips screw securing the cover of the arm, prise off the cover by gently bending the arm outwards, remove the band/spring by bending it inward to disengage the adjustment clip, and extract the earpiece-retaining clip with a small screwdriver or similar.


    Next you need to disassemble the earcup to rescue the white axle that's the heart of the rotation system. The axle is secured to the driver mounting plate by a screw from the back side, but the least violent way to access this is from the pad side. Remove the pad, pop out the driver from the 3 clips that hold it, and remove the screw that hides behind the driver that holds the cup on. I didn't know about that screw the first time, so I wondered why the cup seemed to be 'clipped' to the driver plate so firmly. :rolleyes:

    After unscrewing and extracting the axle shafts, cut off and save the tube on the top of each driver housing that the axles fit into. You'll re-use these.


    Next is where your DIY chops come in. The axle shafts need to be screwed to the KSC75 clips and the resulting assembly mounted back into the JVC headband arms. You need to 1) cut or chisel a flat piece into the back of each Koss clip, removing the wire that's moulded into it; and 2) cut a bit off the top of each clip so everything fits together. I used half a mini hacksaw blade and a small sharp srewdriver for this. You can see at top left in the photo below that I cut the wire first, but you might find it handy to leave it to hold onto while you're doing the first cut. For the second cut, don't initially cut too much - you want the black ferrules cut from the top of the JVC earpieces to fit firmly with no slop between the top of the Koss clip and the limit of how far they slide up the axle.

    To screw the JVC axle into the Koss clip, you could try re-using the JVC screw(s) (there are two extra, the ones that held the cups) but this being the critical potential weak point of the new assembly, you might want to go bigger. I replaced the (I think) M2/3.5mm JVC screws with M2.3/6mm self-tappers. Put the black ferrules from the tops of the JVC earpieces onto the axles before finally screwing the axles to the clips (the left photo below doesn't show them, for clarity in illustrating the next point); and watch which way up the axles are when you screw them on - they have to be mounted with the flat side facing outward as shown in the photo or the cam blocks on the axle bearings won't allow the axles to rotate the right way when everything's re-assembled.

    As mentioned earlier - when mounting the axles, screw them into a position where the black ferrules are a tight fit between the top of the Koss clip and their retainer at the top of the axle shaft. If they're loose, the rotation of the earpiece clips when finally mounted to the arms will be sloppy.


    Reassembly of the arm with the new earpiece clips is just the reverse of the disassembly step: put the axles into the arms, slide in the axle retainer clips, slide in the band and push the adjustment clip under it, and screw the cover back on:


    Clip the Koss earpieces back in, hopefully remembering which is L and which is R - et voila, you have a pair of KSJVC75s :punk:
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  3. Ronion

    Ronion Rando

    Apr 3, 2021
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    I still use those Sennheiser px100-II regularly and enjoy them, but I’ve been looking for something smaller and more portable that will still allow me to hear the outside world and give me an even greater sense of space if possible. I’ve got a slew of earbuds coming in to have a listen. If not, I’m perfectly happy sticking with the px100-II. When I first got them I figured they wouldn’t last long(this cables, lots of moving parts), but that was well over a decade ago and I’ve only had to buy 2 pairs of pads. Can’t complain at all!

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