[kalbee]

Well, if the pads causes the headphones to be unbearable due to discomfort I'd still opt for pad changing and try to find whatever will either improve or preserve the original sound best. At least my leather pad TDS-15 sounds more enjoyable than my stock one. It is, however, only a bit more comfortable. Need to retry with thinner leather but I've had no time lately for audio DIY...

 

[MuZo2]

Wiki says 
Impedance: 16/40/100 ohms - depending on the model
I am not sure which version I have. But compared to Fostex T50rp and Yamaha they are hard to drive directly from DAC
 
 

 

[takato14]

  Wiki says 
Impedance: 16/40/100 ohms - depending on the model
I am not sure which version I have. But compared to Fostex T50rp and Yamaha they are hard to drive directly from DAC
 
 
 

The 40 ohm version is most common, and the Yamaha orthos are way harder to power than this, I've had both at the same time and compared them side by side :/
 
What DAC...? You can't power any headphone from a discrete/separate DAC, you need an amp section of some kind...

 

[longuito]

Hello from the middle of the world,
 
I'm looking for some help with the drivers on my Dual DK830's. They were working / sounding great as ever until I felt a rattle and decided to take them apart and found that the foam spacers / dampers had become dry and caked, with some of the holes on the rear side of the drivers completely covered in gunk.
 
So then, being my OCD self, I decided to go ahead and clean them with a toothbrush, Fantastik (mild household degreaser) and water. When I put them back together, to m surprise one side was gone, dead, NADA. I un-soldered the wires and sure enough, when I used my multimeter I saw there was no conductivity between the one terminal and the other. SO I proceeded to remove the clamps and see if there was any conductivity within the membrane itself and THAT is apparently the problem, almost certainly caused by the use of the chemical.
 
Needless to say, I feel like an ass for having done this, but would like to get some suggestions as to how I could possibly un-f___k up what I did. Ihad thought of the following options:
- using a brush to carefully re-paint the unpainted surface affected by the chemical with a silver based conductive paint, (I suspect that this could affect the resistance of the driver, but would it be perceivable?)
- using a spray applicator, apl;y a uniform coating to both drivers in order to at least guarantee that one side will be the same as the other in terms of resistance
 
Finally, if anyone has any "salvage" drivers lying around, please let me know how much you would want for the, Thanks in advance!
 
Luigi

 

[GREQ]

Wow, that was painful to read.
 
Either the toothbrush has destroyed a connection(s) in the voice coil, or the chemical has destroyed the coil and/or diaphragm. 
Curious to see if someone has a miracle cure here, but I suspect otherwise.
 
Applying conductive paint or adhesive is pointless unless you can identify the break(s) in the voice-wire that runs across the diaphragm, and perform some sort of microsurgery to reconnect it(them).

 

[longuito]

Hi GREQ,
 
Thanks for being gentle on the comments.
 
On your voice wire comment, I am confused since I had always understood that on orthodynamic / planar magnetic drivers, the diaphragm IS the conductor, and there is no actual wire, but that may be a misconception of mine. As I was testing conductivity on the membrane it does happen to conduct, it just doesn't do it from the center to the edges. Please correct me if I'm wrong. Thanks,

 

[takato14]

  Hi GREQ,
 
Thanks for being gentle on the comments.
 
On your voice wire comment, I am confused since I had always understood that on orthodynamic / planar magnetic drivers, the diaphragm IS the conductor, and there is no actual wire, but that may be a misconception of mine. As I was testing conductivity on the membrane it does happen to conduct, it just doesn't do it from the center to the edges. Please correct me if I'm wrong. Thanks,

The wire is "drawn" onto the diaphragm as traces. Think a PCB, but flexible and you have an orthodynamic voice coil.
 
As for a repair, I DO have a spare PMB driver I plan to sell but it appears that the DK830 uses the other variety of PMB drivers so the one I have won't fit. You can, however, painstakingly redraw the botched portion of the voice coil trace using a solder pen... dBel84 has done this a few times with Yamaha YH-1000s. This is not a repair job to be taken lightly though.

 

[nick n]

I hope you find the area that is broken.
Has anything stuck to the magnets or sheared off you can see when you lifted the magnets off ? Sometimes the traces can stick over the years and get torn off in little bits. They are so thin.
Check up at a light source and see if there are any tiny missing bits.
The center area where the driver is pinned is another spot to check. It might not show it completely.
 
You don't need to get crazy on the matched impedance in my opinion while repairing with either a Silver Conductive pen/ink or Electrically conductive epoxy smeared tissue-paper thin. If one gets too low after using a thin bit of repair goop, just add a very small mount to the other driver to balance.
 
Both can be applied with the head of a needle . You don't have to worry about redoing the tiny individual lines so long as the repaired zone is not much more than a few traces wide.
 
 
 I wonder it the Fantastik reacts with metal? If so MAYBE get some deoxit on there later?
 
The 830 is a terrible can ( hear that everyone ====Don't buy them if you see them, tell me about it and I will dispose of it to help you avoid having to do it

)

 

[longuito]

Hey Nick,
 
Thanks for the advice on the repairs. Now I just have to find the patience to do it thoroughly! On the fantastic note, it should be basic so a weak acid like vinegar or peroxide should neutralize it, but I dont know if I'm about to do it...
 
On the 830 comment, if during your noble pursuit to rid the world of such a terrible can, if you do find donors, let me know, hehe!
 
Cheers, great to find such friendly people!

 

[longuito]

Thanks to Takato as well for the helpful tips and pointers!

 

[takato14]

Hey, I just thought of something, I have a working PMB driver with the small-hole magnets, he has a broken one with the large-hole magnets. Couldn't he just swap his botched diaphragm out with the working one from my driver? The diaphragm appears to be the same, take a look:
 

Large hole
 

Small hole
 
Can anyone confirm this? 

 

[longuito]

Hi Takato,
 
The best thing would be to measure the hole or the width of the central axial shaft? I can report the dimensions of mine once I get home. Cheers,
 
Luigi

 

[DefectiveAudioComponent]

  Hey Nick,
 
Thanks for the advice on the repairs. Now I just have to find the patience to do it thoroughly! On the fantastic note, it should be basic so a weak acid like vinegar or peroxide should neutralize it, but I dont know if I'm about to do it...
 
On the 830 comment, if during your noble pursuit to rid the world of such a terrible can, if you do find donors, let me know, hehe!
 
Cheers, great to find such friendly people!

 
How about some high-quality pictures of the membrane now that you have taken it all apart?
 
Some pictures of both magnets may be useful too, there are some variants of it.

 

[longuito]

I will shoot some photos once I get home in a few hours. Regards,

 

[dBel84]

I was trying to follow exactly what happened to the driver - if it is an area of the trace that has been damaged it is not impossible to repair it with conductive ink. The driver swap would be pretty easy too as long as they have the same impedance, not sure how easily the pmb drivers are to split...dB