I was having opportunity to buy open back headphones AKG K612 PRO in a poor condition with broken elastic guides for headband. Refurbishing and some mods are described below.
Headband refurbishing:
- ungluing bottom and upper layer of headband (stitching is not though all layers);
- removing plastic stiffening placed inside of headband;
- stitching bottom and upper layer of headband.
Broken elastic guides for headband have been replaced with new ones cut from polypropylene by laser. Upper assembly cups with labels L/R had to be drill out for disassembly. Due to that new assembly has been made with:
- 3D printed nut-ring,
- nut M3,
- countersunk screw M3 total length 10mm;
- enlarged washer M6 outside diameetr 15mm;
- on top have been sticked orginals labels with letters L, R;
Acoustic filter has been applied according to measurements presented here:
with 3D printed frame
Mod for detachable cable with jack 3.5mm socket and 3D printed fixture
Elastic straps have been replaced with new one (thickness 1mm but might be used thinner diameter as well). I was not aware what is correct length, so I have cut 10% shorter than worn pieces. But it was still too long, due to that I have twisted them several times.
