[Muamp]

Hi -JFK-

Sorry to read about the motorbike accident. Wish you well and a speedy recovery!
That is an awesome panel in the video.
Lovely prototype.

David.

 

[Congo5]

Getting Ribbon cable which is thick enough and ultra soft and flexible (definitely NOT computer ribbon cable which is too stiff and too thin) is a problem. Currently, for the cable I use 'ultra flexible measurement cable' and either 6 strand plait or loosly held with cable clips.
So what I am looking for is "thick, flexible ribbon cable" similar to the cable used by Stax. Just a supplier for the ribbon cable, to make the lead.... Googled many times, to no avail.
 
David.

I looked for that cable also and the closest I could find is Cicoil, available from Digikey.
 
12kv rated High Flex flat cable: http://www.digikey.com/product-search/en/cables-wires/flat-ribbon-cables/1638574?k=&pkeyword=&pv316=11&pv316=3&pv78=9&pv78=10&FV=fff40019%2Cfff800ae%2C14313f%2C5040075&vendor=1233&mnonly=0&newproducts=0&ColumnSort=0&page=1&quantity=0&ptm=0&fid=0&pageSize=25
 
I have not asked Koss for some (probably the best idea) but did find a 100" roll on ebay of Cicoil 10 conductor 20ga and it is nice wire but think 26-28ga would be the right choice.

 

[inuponken]

Just finished my third one. 

 

 

 

[chinsettawong]

Hi Kubo-san,
 
Those headphones look spectacular.  I really like your wooden cases.  What kind of wood do you use?
 
Now that you have 3 pairs of DIY headphones, which one do you like best?
 
I notice the way you make the headband for your JF clone is different from mine,  Do you make the ear pads for them or do you listen to them without ear pads like the original JF?
 
Wachara C.

 

[chinsettawong]

  Hello, 
 
Long time ! (terrible motorbike accident, but I'm alive !)
 
This is my first prototype and it work !
https://drive.google.com/file/d/0B3k06KRLerMUU0RldHRWY3I3WGs/view?usp=sharing
 
Really happy.
Now, head part to do and optimisations !

 
 
Sorry to hear about your motorbike accident.  I wish you a speedy and full recovery.
 
Your driver looks really well made.  I'm sure it sounds sweet.  
 
What kind of amp do you use to drive it?  Your bias voltage circuit looks interesting.  May I know its specification and where you get it from?

 

[-JFK-]

   
 
Sorry to hear about your motorbike accident.  I wish you a speedy and full recovery.
 
Your driver looks really well made.  I'm sure it sounds sweet.  
 
What kind of amp do you use to drive it?  Your bias voltage circuit looks interesting.  May I know its specification and where you get it from?

Hello, 
 
The Amp is a D class from IcePower ref. 50ASX2 SE.
https://www.google.fr/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&uact=8&ved=0ahUKEwiCx4C2t8PQAhVCOBQKHQGLA-AQFggrMAE&url=http%3A%2F%2Fwww.icepower.bang-olufsen.com%2Ffiles%2Fsolutions%2Ficepower50asx2.pdf&usg=AFQjCNEomZmI_iyeLekN0lN4qjaEepECRg&sig2=9HuFt4s3kh4pnY6P-MRcBg
The bias come from Ebay, I'm not good with it because the transformer make a bit of noise at high voltage, but for testing around 600V is good. (less than 10USD...)
http://www.ebay.fr/itm/High-Voltage-DC-DC-Boost-Converter-5V-12V-Step-up-to-300V-1200V-Power-Module-/272192879496?hash=item3f5ff5bb88:g:MoYAAOSwwpdW-59R

 

[Muamp]

Hi inuponken,
 
Those wooden surrounds look incredible!
Can you tell us some technical details about them...? Especially how you made the head band.
Also, what will you do for ear cushions?
 
David.

 

[inuponken]

Wachara, David,
 
Thanks.
 
For the third one, I just modified your design to round shape for more like a

. I used same PCB, Mylar and tensioning for both phones so sounds are nearly the same.  These phones producing wide sound stage and more bass than my SR-407 and Omega clone!!      
I used Red oak for the case and poplar for the face cover. Added “GUNSTOCK” wood stain and coated with semi-gloss Polyurethane.
 
I’m not added ear pads and cloth grills that reduce clarity and presence.
And Instead of use the punching metals, cut the silver mesh magazine file. 
 
http://www.containerstore.com/s/silver-mesh-magazine-file/d?productId=10004834&q=mesh%20file
 
I used BATES stainless ruler BNR-12 for the head band, covered with thin leather sheet.
Arms and face plates are 3/16” black Delrin sheet.     
 

 

 

 

 

[Muamp]

Hi inuponken,

Firstly, the steel rule for the head band is a brilliant idea. Probably the correct amount of spring and stiffness.
The silver mesh magazine file for the external grids is also good.
Really good inventive ideas!

David.

 

[chinsettawong]

Hi Kubo-san,
 
You have got some very nice ideas.  Especially the way you make the headband, it's simply splendid.  
 
Are you saying that even without using ear pads, your new headphones have more bass than SR407?  If that's so, it's a marvelous achievement.  What spacer thickness are you using?

 

[inuponken]

Yes, both phones have more bass than my SR407.  Spacer thickness is 0.8 mm.  
 
Tension is very low, only used small clips to add tensions then added heat until wrinkle is gone.
This is my method that after I repeated trial and error many times...   
 
I think low frequency is also related to the housing, decreased bass when I tested without housing so.

 

[chinsettawong]

I see.  Since your spacer thickness is rather big, it's OK to just heat shrink your diaphragms.
 
However, you lose a lot of efficiency.  If you can, please try again the 0.5 mm spacers.  All of my phones including JF clone now are using 0.5 mm spacers.  The efficiency is good and the bass is very nice too.

 

[Muamp]

Just finished my latest pair of ESHS, which are my first pair to be completely 100% home/hand made.
No bought in parts, apart from raw materials are used!
Listened to them for a few hours last night and definately my favourite ESHS (so far).
 

 

 

 

 

 

 

 

 

 
 
I am now going to make another pair almost the same as these for another Head-Fi 'er. I promised him a pair more than a year ago. He's been quite patient.
 
I am also looking into PCB production in China, so that I can get a batch of stators made in one go. The stators will be identical to the ones in these ESHS.
The PCB company have already rejected my first set of Gerber files, so I will have to check out what it is I have to change in the files I submit.
 
David.

 

[chinsettawong]

Hi David,

Congratulations! Your headphones look great. Nothing sounds better than the DIY ones. I'm sure.

Looking forwards to seeing more headphones from you.

By the way, what is your spacer thickness? How do you like the bass?

Wachara C.

 

[Muamp]

Hi Wachara C,
 
They are just a slight variation from the older ones, but all home made, including the ear cushions. Yes, I did sow them myself.
Now I only use 1mm FR4 stators. These have 1.7mm holes and centre cut out of 8mm, sprayed with black acrylic on both sides.
1/2mm FR4 spacers. Since they are 1/2mm spacers the top end is excellent and also similar sensitivity to my Stax phones.
The tension on the diaphragm is high, but not too high to destroy the bass.
Dust protectors on all sides. With 1/2mm spacers you cannot get away without them.
 
I keep thinking about building some JF clones, but..... I have just kept on experimenting with different build materials on my round panels. Now I am definately settled on FR4 for stators and spacers!
I now only use 1/2mm spacers, but if I can get 0.4mm FR4, which I think I can source in China, I will have a go.
 
David.