Recable DT770s
Apr 27, 2013 at 12:58 AM Thread Starter Post #1 of 40

liquidzoo

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So, I've been thinking about recabling my DT770s (80 Ohm) with a removable cable. I'm thinking about going mini XLR on the cup side and I have a question.

I've seen pictures of the inside of the cups, so I know about the 3 (impossibly thin) wires connecting to the left cup, which I'm sure I could replace with small segments of whatever wire I choose to use (I will have to replace the wires to the right cup if I choose to use silver (if anyone has done this, how does silver wire affect the sound on the 770s?)).

Part 1 of my question:

One of these wires is left and one is shield (ground?). The other (center wire) is right?

Part 2:

Assuming I'm not going to prepare these for balanced output (should I? Is there a benefit?), does it matter which pin I solder what wire to? Assuming, of course, that I repeat the same wiring scheme on the other (female) connector?
 
Apr 27, 2013 at 2:40 AM Post #2 of 40
Quote:
So, I've been thinking about recabling my DT770s (80 Ohm) with a removable cable. I'm thinking about going mini XLR on the cup side and I have a question.

I've seen pictures of the inside of the cups, so I know about the 3 (impossibly thin) wires connecting to the left cup, which I'm sure I could replace with small segments of whatever wire I choose to use (I will have to replace the wires to the right cup if I choose to use silver (if anyone has done this, how does silver wire affect the sound on the 770s?)).

Part 1 of my question:

One of these wires is left and one is shield (ground?). The other (center wire) is right?

Part 2:

Assuming I'm not going to prepare these for balanced output (should I? Is there a benefit?), does it matter which pin I solder what wire to? Assuming, of course, that I repeat the same wiring scheme on the other (female) connector?

 
 
Scrap 3 pin XLR, and go for a small good quality 3.5mm jack. 3 pin XLR is not balanced and can be kind of big which means you would be cutting up your DT770s quite a bit. A nice small 3.5mm jack is all you need since it would do the same exact job as XLR would in this case. 
 
 
If you were to use XLR, If you continued to use the same pin layout, no....it would not matter. However, I would be consistent with the pin layout because if you ever forget how you wired the cable, your screwed. If you ever forget how you properly wired the cables, then you can google it. 
 
May 16, 2013 at 11:35 PM Post #4 of 40
Ok...freaking out a bit right now (I'm hoping I'm still ok...)
 
Opened the left cup to run my removable cable.  Had a minor freak out moment when I snipped the existing wires, but that's passed.
 
I widened the cable entry hole a bit, no problem.
 
Freak out moment came when I was desoldering the stock cable (I wrote down what wire went where first).
 
First 2 wires from the right went ok.  The farthest right being the easiest, since it only had 1 wire on it.  I am using a Weller 25W soldering iron and some desoldering braid (wick) from Rat Shack.
 
Second wire was a little tougher and I thought that the post moved ever so slightly in the moment when the solder started to melt into the wick.
 
Third (farthest left, Ground wire) was the hardest and when the solder finally started to move the post definitely moved.
 
I checked and the hair thin wires on the under side are undisturbed and the post seems solid now that everything has cooled down (which it did almost instantly after I took the iron away).
 
I'm hoping that I didn't just ruin the driver...
 
Anyone else had this happen and can comment? 
 
May 17, 2013 at 9:20 AM Post #5 of 40
As long as the wires are still intact, you're good. Heating up the post also heated up the glue/plastic that's holding the post to the driver. It's pretty annoying to deal with and freaked me out the first time as well. If possible, try to find a way to heatsink the end of the post closes to the driver with like a alligator clip or something. It's either that or work fast and carefully. gl!
 
May 17, 2013 at 10:32 AM Post #6 of 40
Quote:
As long as the wires are still intact, you're good. Heating up the post also heated up the glue/plastic that's holding the post to the driver. It's pretty annoying to deal with and freaked me out the first time as well. If possible, try to find a way to heatsink the end of the post closes to the driver with like a alligator clip or something. It's either that or work fast and carefully. gl!

That makes me feel a lot better about the situation, thanks.
 
I need to clean up that last post a bit before I start wiring in the xlr (plus I need to double check clearance).  Will post pics when everything is done.  I've been taking them along the way.
 
May 18, 2013 at 9:05 AM Post #7 of 40
Mini XLr's are quite annoying to deal with ImHO, I balanced my Q701 with a 4 Pin, and it was really a pain, compared to TRS. It also takes a lot of effort to unplug the cable. It does lock in though, which is actually worse for cable since stress can break the headphones instead of unplugging the cable. But, they do lock, and they are more professional looking, So ull be fine :)
 
May 19, 2013 at 2:09 PM Post #8 of 40
So mad...

Got the xlr in, got it wired up and the nut was in the way of the driver sitting right. No biggie, I thought...

Took the driver back out and the negative terminal came out.

Broken driver. Ruined it. Now I'm pissed because I have no headphones for my trip tomorrow.
 
Jun 2, 2013 at 10:51 PM Post #9 of 40
Probably too late BUT...
 
I did the same conversion to my DT880's and the ground tab from one of the drivers pulled out of the plastic as well.
mad.gif

I was very luck as the hair wire from the voice coil broke off right at the lower tang and not down by the plastic mount. I got some magnification out and managed to wrap the voice coil wire around the middle tang instead, just a half bend and then applied solder to the little tang. Measured with the meter and all was good, you might want to check where the voice coil wire broke off as you might be able to easily salvage the driver.
 

 
Good Luck!
 
Jun 3, 2013 at 11:29 AM Post #10 of 40
Quote:
Probably too late BUT...
 
I did the same conversion to my DT880's and the ground tab from one of the drivers pulled out of the plastic as well.
mad.gif

I was very luck as the hair wire from the voice coil broke off right at the lower tang and not down by the plastic mount. I got some magnification out and managed to wrap the voice coil wire around the middle tang instead, just a half bend and then applied solder to the little tang. Measured with the meter and all was good, you might want to check where the voice coil wire broke off as you might be able to easily salvage the driver.
 
 
 
Good Luck!

 
Thanks for the advice, those 880s look awesome.
 
I will check on the wire.  I still have everything, and I haven't checked to see if the wire is salvageable.
 
1 question:
 
How did you get the XLR in there and the driver to sit flat?  The nut seems to get in the way of mine going all the way flat.  
 
Pretty sure that's the reason the tab broke off in the first place.
 
Jun 3, 2013 at 12:14 PM Post #11 of 40
Hey liquidzoo!
Thanks it was a fun mod, till I broke the wire and then the air was blue...
biggrin.gif

 
There is not enough room for the hex nut in there.
 
I made the mounting hole so that one edge of it was level with the little ridge in the cup that the driver rests on. Also make sure you turn the flat spot on the XLR socket towards the driver just to give you a little more room. Once the fit was all tested and it looked good, i mixed up a batch of J-B Weld KwikWeld and applied it to the hole in the cup. Slid in the socket with the flat spot up so the driver has a place to rest on it, surrounded the part where the socket comes through the hole with more KwikWeld and put a clamp between the back of the cup and the flat part of the XLR socket.
 
Basically you are clamping down towards the back of the cup. make sure you push in the socket firmly while you apply the downward clamping pressure, The edge of the cup where the socket mounts is rounded and you cannot get the XLR socket to sit perfectly flush, if you do then the socket goes in at an angle and interferes with the driver. If you know what I mean.
 
J-B Weld KwikWeld sets up very fast (4 minutes) so make sure you are all ready to go, with clamps and everything.
 
Good luck and I hope you can recover your DT770's!
 
Jun 3, 2013 at 12:48 PM Post #12 of 40
Thanks for the tip!
 
I will keep this thread posted on the salvageability of the driver.  I have already contacted Beyer and found that it's $57 for a new driver if I need one.  If I can't salvage, I will buy a new one (though I will have to burn it in).
 
Jun 3, 2013 at 1:23 PM Post #13 of 40
If you do have to get a new driver, measure your old one with a meter to see what resistance it is and let them know when you order your new one.
Mine measure 235.5 and 236 ohms respectively. Yours will be different since they are 80 ohm drivers.

Sent from my HTC Desire HD A9191 using Tapatalk 2
 
Jun 3, 2013 at 2:21 PM Post #15 of 40
Quote:
If you do have to get a new driver, measure your old one with a meter to see what resistance it is and let them know when you order your new one.
Mine measure 235.5 and 236 ohms respectively. Yours will be different since they are 80 ohm drivers.

Sent from my HTC Desire HD A9191 using Tapatalk 2

I will do so, thanks.
Quote:
*cheap plug* Or you can buy my spare driver for $45 shipped! ^_^ *cheap plug*

Hehe.  I may very well take you up on that.  Let me take a closer look at the voice coil wire tonight so I can make my decision.
 

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