HELP NEEDED!!! Wiring stock HD650 connectors (PICS!!!)

[rsaavedra]

Building an aftermarket cable for my Senns HD650, final step was to solder the stock cable connectors. Cut them off from the stock cable and peeled the external jacket off, then a thinner internal jacket, and here's the surprise:

Those wires in the sennheiser cable have some enamel-like insulation. They won't make contact as they come in the pic. I must remove that insulation somehow. That's the question. How?

Used my lighter (basically a little torch) trying to burn the thing off, and it does burn something off, but actually doesn't leave the wires' surface with perfect conductivity at the touch of the multimeter's probe.

How can I make those wires really clean to make sure an excellent electrical contact will be achieved when soldering those wires to my DIY aftermarket cable?

Any help/recommendations greatly appreciated. Thanks!

 

[fran]

Paint stripper?

 

[Sovkiller]

Warm the soldering iron, and apply hot solder, the heat will eventually remove the paint, if it is paint and not a teflon based coating

 

[sejarzo]

Don't use just any stripper, it might only corrode the copper and not really leave a clean surface. Wire enamel is "crosslinked" like fiberglass resin, so it isn't actually very soluble in anything.

Google is your friend.......I simply entered the words:

remove wire enamel solder

and got a variety of good info. This advice is from http://www.ladyada.net/make/tutorials/soldering.pdf :

+++++++++++++++++
CLEANING AND TINNING HEAT-STRIPPABLE ENAMELED LEADS
Many enamel-insulated copper wires use a 'heat-strippable' enamel. You can usually identify this type of wire by its color. Most NON-heat-strippable enamels are of a dark color (often a brownish-red), while most heat-strippable enamels are of a much lighter, translucent color (generally red, green, or an orange-yellow). [Note: from your picture, it sure looks like this is what Senn uses, a heat-strippable enamel.]

Measure and clip the lead to a length slightly longer than that required by the joint. Using a HOT (725 °F / 385 °C, or hotter) soldering iron with a medium width (.05" / 1.25mm) tip, melt a 'blob' of solder onto the tip of the iron.

Insert the clipped end of the wire into the solder blob and wait a few seconds for the heatstrippable enamel to begin to smoke and bubble. As the enamel begins to bubble, insert more of the wire into the solder blob. Adding a bit more solder to the new rosin will assist in the tinning process.

Once you have inserted the lead to the length required, slowly pull the wire back out of the solder blob. This should produce a nicely tinned lead with possibly a bit of burnt rosin remaining on the outside of the tinned lead. Any remaining rosin can be easily removed by pulling the wire between your index finger and your thumbnail.
+++++++++++++++++

 

[rsaavedra]

Wow thanks a lot to all for all the help!!! I did search Google actually, but didn't use those exact key words, never found anything too helpful like that technique.

Unfortunately I already applied the lighter torch directly to the wire, not sure whether that damaged the copper somehow. I might get a new stock cable to try that technique with the solder blob.


PS. Gee with those proprietary connectors, Sennheiser left really little room to make a DIY aftermarket cable easy.

 

[rsaavedra]

Applied the solder blob technique (thanks again Sejarzo!) on some still available remaning wires of the connectors, and conductivity achieved was really excellent. The final cable offers 0.2 Ohms, compared to 0.6 of my slightly shorter Zu Mobius. Check out some pics and further comments on that at the DIY cable gallery:

http://www.head-fi.org/forums/showpo...postcount=2628

 

[soloz2]

the best method is to use a solder pot.

 

[luidge]

So how does it sound? Are you happy with the result? Look great anyway hehe

 

[rsaavedra]

Don't want to write any extensive review but let me put it in my sisters' words. She claims to be no audiophile at all, and claims to have a very poor ear. I gave her the HD650s with the new cable first, played ticks & leeches by Tool, a song she likes. Then played the same song but the headphones connected with the Zu. In her words, the Zu has the sound more "hidden" or dark, but sounds "cleaner". Whatever that means to her. So I asked her in any case you do perceive a difference with one cable vs. the other and she says definitely yes. She prefers the Zu.

Now from my own ears, apparently the Zu has clearer top-end and better lowest bass definition, so better extension overall. Now, when I say extension, not sure if it's actually signal amplitude at the extremes, maybe it's just more accuracy at the extremes.

Playing Perfect Circle's "Go back to sleep" which has a very deep recurrent low bass, sounds better defined with the Zu. However, playing Dire Straits' "So far away from me", the guitar and bass lines sound more prominent and clearer, more resonant even, with the new cable; yet the high frequencies of the tambourine shimmer sounds cleaner and clearer on the Zu.

If frequency responses could be measured on cables, what I'm hearing could be correlated to the Zu showing a mildly concave or flatter response, both extremes probably even mildly higher than the midrange, while the new cable might have the response mildly convex, slightly more prominent midrange, and not as prominent at the extremes. If it's not actually amplitude response, so let's say both are actually equally flat, then there would seem to be a difference in accuracy on the frecuencies at the extremes. Slightly missing or not as great "resolution" (in other words, more distortion levels maybe) on the new cable at the extremes. Yet at the mids, the sound to me has something apparently better on the new cable compared to the Zu.

Definitely there should be freq. response measurements on cables, as well as resistance, capacitance, and inductance standard measurements to compare their physical specs. That would be measured including everything in the cable, not just the wires but also plugs and connectors. Actually, some measurement of distortions/attenuations at different frequencies introduced by a particular length of a particular cable (again with plugs and connectors) could also be useful.

 

[nikongod]

i find its better to first scrape a bunch of the enamel off with a cheap hoby knife (x-acto) and THEN do the solder "dipping" thing above. if i had a solder-pot, i would scrape then do that.