Replacing your stock hd 25-1 cable with your stock hd 650 cable
Mar 12, 2005 at 4:30 AM Thread Starter Post #1 of 1

Graz

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There are bits & pieces of how to do this in other threads...but, I thought I'd create a "how-to" thread dedicated to the topic.

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Changing from the stock cable to the hd650 cable isn't too tough & honestly, for most of you, this tutorial is unnecessary. But it may be helpful for some, so here goes...

The stock configuration on the hd 25 has both left & right channel wires routed to the right ear cup. This results in unequal length wires since the left channel wire has to run the extra distance over the headband to reach the left ear cup. The headband has a groove that the wire fits snugly into...this groove is exposed when you pull the split-headband halves apart & the cable is easily removed from this groove.

The hd650 cable basically won't allow for the same configuration (at least it didn't for me). The 650 cable is designed to route the wires separately to each cup (with the split occurring somewhere near your sternum as you wear them). Subsequently, the extra length for routing the left channel wire over the headband isn't there. Yea, you could create the unequal length configuration with some modification, but even with that, the insulation on the 650 cable is significantly fatter than what's on the hd 25 cable. See picture here (the stock hd 25 cable is on the left):
dsc008332ml.jpg


In the end, I just couldn't squeeze the fatter 650 cable into the headband groove. I guess if you just had to retain the original hd 25 configuration, you could route the left channel wire over the headband & secure it with some cable ties (or some other method), but you'd also have to do some cutting & re-soldering to achieve the unequal length configuration...in the end, for me, it just made more sense to go with the hd650 arrangement.

So first, remove the stock cable. You'll have to remove the two screws at the right earcup, pull the left channel wire out of the groove, and remove the connectors from each earcup...just grasp the connector firmly, and pull them out. Note that one pin is slightly larger than the other (and the receptacle holes are sized differently)...be sure to match the pin/hole sizes when inserting the hd 650 cable (but if you've upgraded your 650 with an aftermarket cable, and you're performing this mod with the leftover stock 650 cable...you already knew this).

The stock configuration has the connectors inserting into the cups from the top side, but you do have two options:
Option 1: Keeping the stock configuration with connectors inserting from the top side
This configuration retains strain relief for the connectors and the cables, so while it requires a bit more work, it may be preferable...
If you decide to go this route, you'll find that the distance from the left/right cable split point (where the overmold is) to the connector ends is too short...without modification, you'd end up with the split point right under your chin. So, you'll have to remove the overmold at the split point & pull the left & right cable halves apart to create some extra length between the split point & the connector ends. If you're careful & use a nice, sharp exacto blade, you can remove the overmold & still re-use it later (as I've done). If not, I guess you could just use a nylon cable tie at the split point, or I guess you could even just go with nothing. After completing the above, my split point ended up looking like the pic below. I applied some glue to the inside of the overmold, re-inserted the wires, and finished it with some heat shrink tubing.
dsc008319tn.jpg


Since the hd 25 only has a securing point for the cable on its right-side earcup, you may want to figure out a securing method for the left-side cable. Again, I guess you could go with nothing or a nylon cable tie (or your own method, whatever that might be). I used some heat shrink tubing. The end result looks like this:
dsc008306jb.jpg


Option 2: Cable exits from the bottom
The obvious alternative to Option 1 is to simply flip the cups around 180 degrees so that the connectors point straight down. This is definitely a viable alternative, but as there is no strain relief with this configuration, there will be some stress on the connectors and the cables over time. In the end, I did end going with Option 2 (in spite of the risks) even though this is not shown in the pics. I think aesthetically, this option is a little better...the wiring ends up looking a little cleaner, imo. As a side note, if you do decide to flip the cups around with the connectors pointing down, it is possible to remove the hd-25 badge on the left earcup and flip it 180 degrees as well to match the new configuration. If I remember correctly, there are some plastic alignment nubs in there, but they can be safely clipped off & the badge will still stay firmly in place without them.

Next you need to decide if you want to keep the 1/4" jack from the stock 650 cable (and use some sort of adapter when you wanna go with 1/8"). I use my hd 25 most often in my mobile rig, so I definitely wanted 1/8" only. I also used this modification opportunity to cut some of the length out of the cable. It was too long for my mobile needs.
So...if you decide to go this route, you'll need to know a couple of things. The ground/signal conductors inside the hd 650 cables route in the same groove. They are stranded, and color coded. As I recall, there is a copper-colored grouping and a green grouping. Each and every strand inside each grouping is covered with a non-conductive, colored coating which allows them to route in this single groove without making contact between the signal grouping and the ground grouping. I had some concerns about soldering due to the non-conductive coating, but after some experimentation, I discovered that by applying a soldering iron & some solder directly to the coated wires, the non-conductive coating melts right off & allows the solder to do it's thing. So the non-conductive coating ends up being a non-issue really. Just twist the color-coded grouping together and solder as you normally would & watch the coating melt away. ***Very Important! Make sure you don't mix any of the copper-colored strands with any of the green strands or vice versa! Just one strand is all it takes to create a short between signal & ground.*** It's not apparent which color is ground & which color is signal...and I don't remember. Just use a multimeter & measure to be sure.

I found a nice little Neutrik right-angle plug at www.thlaudio.com ... this was what I used & the end result is pictured here:
dsc008292to.jpg


Here's the finished product:
dsc008321nn.jpg


Peace,

Graz
 

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