[Cidious]

Dear Head-Fi community,
 
Since half a year I am working and living in China and I am having tons of free time on my hands. That combined with the AWESOMENESS of Taobao.com to get ANYTHING I would want, made me step into the Audio DIY world. I started with upgrading an Aune T1 and a Aune X1SE. Upgraded their power supplies and recapped the **** out of em. Then I build two Lehmann BCL clones which I wrote about in the Lovely Cube topic hear on this forum. Was not enough building a DAC now. Still I felt unsatisfied. 
 
I own several nice grade headphones. Mr Speakers Mad Dog, Beyerdynamic DT 770, Beyerdynamic DT 1770 and a pair of Audio Technica ATH-M50X with some Shure pads. From these cans I mostly listen to the DT 1770 and Mad Dogs. Very nice headsets. 
 
The Mad Dogs are really fun to listen to and the most amazing thing is their lust for power. I can just keep putting power in to them and the volume just rises over the full audio spectrum. Not like with most cans that one particular area starts opening up and starts hurting before the other ranges are even near the same volume level. Really fantastic technology the Planar Magnetic drivers. I am planning to buy a Fostex T50RP MK3 and mod that one myself with some self made sheep leather pads and upgraded internals. 
 
But thats not why I'm making this post. I really like the DT 1770. They are near perfect. Still I would like to make some changes. Better mids for example. Even though they are not as recessed as the DT 770 they are still lacking. I have checked the DT 1770 mod thread on this forum and I have decided not to lose my warranty on them.. I want to keep the resell value stable. I do have another pair of DT 770 that have the same design but are really ****ty cans compared to the others.. The sound is far from natural.. Really annoying metallic sound in the mids. Female vocals pierce my ear on every new note.. I do love the bass though.. I could tune these a bit and solve some of its problems but I've decided to do it even better.
 
 
What will I do?
 

1. I have bought some 600 ohm 50mm Tesla drivers and I will rework the housing to make them fit. Standard the DT 770 has 45mm drivers and the 50mm will not nearly fit. I am currently redesigning the driver frame in Tinkercad to have them 3D printed in a 3D print shop around here.
2. I will redo internal wiring with high grade silver plated copper wire
3. I will replace the cable with a replaceable Canare L-4E6S mini XLR -> 6.35mm cable
4. This also means making a Mini XLR connector in the housing
5. I've ordered some pleather DT 770M pads and I will also order some DT 990 velours pads to which sounds best and is most comfortable and make it more in line with the black DT 1770
6. I will make a nice sheep leather and memory foam padded headband for it
7. And finally I will tune it to my liking with all kinds of materials I've bought for it
8. Maybe I will even customize the outside. Thinking of smoothening the ugly outside texture and rubber texture painting them matte black and giving them some sort of custom model number. Like "DT 770 Tesla 600 ohm"

 
 

 
Most parts. Some still incoming. What you see:

1. High grade silver plated copper wire
2. Dampening paper (some kind of fibers, but with a smooth back side. Not as open as the original Beyer paper. I will keep looking)
3. Filt (will get some more of this)
4. Bass port dots. (Self adhesive. Two kind of materials. I can decrease or increase the bass port flow by putting more or less of them on the hole)
5. Tesla drivers (50mm 600ohm. I had them 4cm away from eachother and suddenly they pulled themself together. Could barely get them off eachother. Crazy strong magnets! They can push each other away over 6 cm)
6. Original drivers (just for comparison) 
7. Disassembled DT 770 Pro 250 Ohm

 
 
Close up

 
 
Comparisson

 
 
I would love people to make suggestions and I will keep you guys posted with the progress.
 
 
Greets.
Marlon

 

[Cidious]

I've made a nice discovery.
 
By browsing some of the Taobao shops that all sell the same driver. I've found out that the actual driver is exactly 45mm and able to fit in any DT880, DT770, DT1770 and I also think DT990. But I need to mod it a bit. Replace the terminals. I've no experience with this.
 
I will show here what I mean. 
 
Driver as I have it


 
Without frame

 
Exactly 45mm as I've measured

 
These pictures are from a DIY customer that modified them to fit his DT880. 

 

 

 
I just need to figure out how. I don't have any idea how the terminals work. If someone could help me out here a bit and help explaining how this could be achieved, that would be amazingly helpful! 
Sadly the customer that has done this mod is untraceable, and he probably only speaks Chinese anyway. 
 
Looking forward to tips.
 
 
Greets,
Marlon

 

[Cidious]

Spamming my own thread but here pictures of my drivers and their terminal connections
 

 

 
Thats REALLY thin wire! And I see its not even distributed.. How is it even attached to the magnet? Glue can't be good because it will insulate.. I'm confused.. What to do? 
 
I would really love to use the original driver frame from the DT770 and make the drivers compatible with every other Beyer headphone with 45mm drivers. But the drivers were NOT cheap and I don't want to ruin them.. 
 
Any tips REALLY welcome.

 

[Eudis]

Do you have a link for both drivers?

 

[Cidious]

Why? You want to know a price? What do you want to know about them?

 

[Eudis]

I would like to obtain a pair. I saw some updated (metal top) dt880/990 drivers for like $10. I didn't want to get some fakes.

 

[Eudis]

I want to do a little side project where I'll redesign the entire enclosure and tweak the drivers to see if I can tame the highs and bring up the mids. I'm learning everything from scratch which is nice.

 

[Cidious]

These were not $10 these were $70.. EACH! Haha. But I bought them on taobao.com I don't think this shop shops internationally but I will ask.

 

[Cidious]

Little update. Busy with a lot of projects.
 
Modeled a new driver frame based on the DT770 and DT1770 driver frame. Little problem is the distance of the driver. Since it has this ring around it, the driver is more back than in the DT770 and DT1770.. This can (will) have an impact on acoustics. Not sure how it will work out. So I'll try and if it's not to my liking I will remove the rings after all.. It will be a tricky job so I hope I can avoid it.
 
Did the modeling with Windows 3D builder.. took me an hour or two to get it right. Very easy. 
 

 

[Cidious]

I need some help on the internal and semi-internal wiring of the cans. 
 
 
The XLR connectors is on the left and originally there was one shielde single core cable running across the headband to the right driver. The shielding was used to connect to the ground. 
 

1. I have some high quality 0.5mm 7n copper and silverplated wire lying around with 30 cores, which I intended to use on the internal wiring of these cans I have a few meter in black red an transparent. This is really good wire but it's maybe a bit on the thin side and I would have to run it across the headband unshielded.. Maybe not the best choice..
2. Next to that I have some dual core shielded and twisted 5n copper wire, also silver plated. Really though wire. But the diameter is 1mm. Which might be a little on the thick side.. Not sure how this would express itself in audible difference between the drivers.. 
3. From this same 1mm wire I also have an unshielded single core variant.. Also a 0.5mm variant but I don't have it in a shielded 0.5mm variant to cross the headband with.
4. I also have some pure silver wire, but it's a bit weird.. It has no isolation. It consist of a solid core with a spiraled outer shell wrapped around it. It's 1mm  thick in total.

 

 
Is shielding over this distance to the other driver a really important thing? and what wire thickness would you guys recommend to cross?

 

[Cidious]

Update:
 
Got the first version of my driver frames in. And first revision is quite right on the spot.. except for the 3D printshop that printed in white and not black.. I can order some new ones free of cost. So I looked at them to remodel them a bit.. but there is no need I think. The drivers fit EXACTLY. I can mount them without glue and they are rock solid. The only thing I'm wondering about is if the diaphragm has enoug space to move. I gave it 1mm extra from the ring. I think it has enough space and I would love to try out a set without this 1mm to get the drivers a bit more forward but I'm scared that on high volume with low bass the diaphragm will tough it's guard frame. So maybe I'll test that later but for now let's keep it safe and start with the internal wiring. 
 

 

 

 

 
I'm still not sure on the wiring. I have fine quality wire laying around but the shielded version has a 1 mm core thickness (which I think is a bit overkill) and the other is 0.5mm but is unshielded. I could braid or twist it to the other side but i'm still a bit scared that 0.5mm might not be thick enough for the distance over the headband and will give a left/right imbalance.. 
 
If someone could please bend over these questions and help me clearing them up, I would be really grateful!

 

[przem]

@Cidious, you should get in touch with @michauczok to make nice wooden cups for those, instead of those ugly plastic ones.

 

[Cidious]

I can make wooden cups myself but I think wood is ugly for headphones.. just don't like it combined with audio equipment in my room.. could be great in a more classically designed room.

I will design my own cups from ABS and a new leather headband. I want to keep the design close to the Beyerdynamic design line.

Wooden cups I can buy or make anytime here. I was thinking about redesigning the DT770 cups and rubber coating them matt black with some nice model number on it. DT770 Tesla instead of Pro. I want to do something different than every chinese shop does here.. wooden cups I can just buy in every shape and size. Wood is for tables and chairs haha. Better would be a aluminum design but I think it will be to heavy including the drivers.

 

[Eudis]

If you want my opinion, make the headphones balanced MINI XLR. 

 

[Cidious]

Of course it will have mini XLR. I don't have a balanced xlr headamp right now but I have a balanced dac so probably building a balanced headamp could be a next challenge. So yes. It will have a mini xlr connector so I can change cables. I have enough Canare L-4E6S to make a nice cable in every color of the rainbow with some Neutrik or Amphenol connectors.