Now that I have completed my Crack Headphones I thought I would write up my experience, hopefully to help others. First off I want to warn everyone that the drivers in the headphones will not sound very good until you break them in. After I finally put the ear pads on I hurried to give them a listen. I plugged them in and cannot sufficiently express my disappointment. This disappointment was short lived however. Following a recommendation from PB, I broke them in at loud volume for a few hours, and they already sound much better. I can’t believe how much of a difference even 3 hours of heavy break-in made. I will give an update after they are fully broken in. The only other caveat I will mention is that there is a natural difference in sound between closed back headphones and open headphones. Keep this in mind when comparing them to other headphones. Now on the the build!
The small TRS plug is probably the hardest part of the entire build. The cable is large enough that it is very hard to get a good electrical and mechanical connection. I ended up soldering the shield and then crimping to the cable alone. The trick here is to lightly tin the shield wire, keeping it flat and about the same width as the shield terminal of the TRS plug. Then lightly tin the terminal as well. Finally, using a heat sink clip, clamp the shield wire to the terminal. Then use the soldering iron to join the two. This procedure will ensure that the joint will be thin enough to fit in the cover. If you are going to solder the shield, I recommend soldering the shield first and then do the tip and ring.
Another sticky (sic) point is the application of the adhesive lined heat shrink tubing. Remember that the heat shrink will shrink in length as well as in diameter. During shrinking the tubing will pull back on the plug jacket, leaving a coating of glue. I would recommend using a little longer piece of tubing and start heating at the cable end. Angle the heat gun so only the tubing is heated, do not let the hot air blow on the tech-flex or it will melt. Starting at the cable end will keep the tubing from moving during shrinking.
I also soldered the shield of the other end of the cable. This was much easier however since there is a hook in the shield terminal to allow this. Simply twist the shield wire and loop it through the hook. Then crimp the clip and solder. Do this first before soldering the tip and ring connections to the resistors. When soldering the wire to the resistors for the tip and ring connections, push the heat shrink tubing back away from the area to be soldered and use a heat sink clip to hold it out of the way. This will keep the tubing from shrinking due to the heat from the soldering iron. Before heating the outer heat shrink tubing, push it all the way up the rear of the plug. It will fit. Heat the shrink tubing starting at the cable end just like the small end.
The damping material is actually very straightforward. I used a plastic tool to burnish the damping tape. Be careful NOT to use your finger to burnish, the edges are sharp and will cut your finger. I learned this the hard way. Removing the paper from the back of the felt is a little tricky, but if you hold the edge of the felt with your fingers and use a small jeweler’s screwdriver to get between the glue tape and the paper it will be much easier.
That’s it. I hope this is useful.
