[chinsettawong]

I've cut all the necessary parts and etched the unneeded copper on the PCB. If time permitted, I should be able to test them within 2 days. 
 

 

 

 
Chemically etching a PCB to me is very difficult.  The result isn't pretty, but for an experiment, I think it will do just fine. 
 
Wachara C.
 
 

 

[pabbi1]

Wachara, just inspirational. Watching with the keenest interest.

 

[Uncle Erik]

Wachara, that's some fine work there. Please keep us updated!

 

[McGyver]

Nice work Wachara!

 
Why dont you route the PCBs instead?
 
Are you using FeCl or HCl when you etch the boards?
 
I use HCl - you have to be careful and do it outside, but I find it faster and easier to get good results!
 
/Roger
 
 
 
 

 

[chinsettawong]

Hi Roger,
 
I'm not sure what chemical I used, but it etched out the copper pretty quickly.  The reason why I didn't route the PCB is because I have some problems of unevenness of the machine surface.  The tolerance of PCB is very small and therefore I decide to use chemical etching.
 
Wachara C.

 

[chinsettawong]

I've just finished putting everything together.  Here are some pictures.
 

 

 

 

 

 

 
Wachara C.

 

[chinsettawong]

The first listening impression is that these headphones are a lot more efficient than my previous version.  The main reasons should be the thinner spacers in them and having 2 diaphragms on each side.  However, I feel rather uncomfortable listening to them.  My ears feel rather uneasy.  I'm not sure if it's because of the greater force pushing and pulling the air inside my ears or I'm just too tired.
 
Let me give them a few days to play lots of songs and I'll report back.
 
Now I'll need to look for a proper headband for them. 
 
Wachara C.

 

[00940]

This is, without a doubt, the thread that amazes most on the whole forum. Outstanding work.
 
 

 

[spritzer]

Even the huge SR-Omega drivers don't push and pull the air, they excite it via vibration so I doubt that is the issue here.  What bias and diaphragm/stator spacing are you using?

 

[elliot42]

:basshead: Amazing.

 

[jgazal]

 
Great work!
 
 
I wish you had access to a distortion analyzer, like the one in this system: http://www.klippel.de/our-products/rd-system.html
 
I suspect what spritzer have in mind. Could the diaphrams be touching the stators? That could increase distortion and thus the fatigue.
 
We are looking forward to hearing your next report.
 
 

 

[frank2908]

subscribed
 

 

[chinsettawong]

Quote:

Even the huge SR-Omega drivers don't push and pull the air, they excite it via vibration so I doubt that is the issue here.  What bias and diaphragm/stator spacing are you using?

Hi Spritzer,
 
I'm using 0.5 mm plastic as spacers and the bias voltage is 600V.  The diaphragm is 1 micron Mylar.
 
Unfortunately I can't listen to them today as I'm away for a business trip.  I was really exhausted after I put everything together last night.  I'll try them again tomorrow night and see if I like them better.
 
Wachara C.
 
 

 

[spritzer]

0.5mm and 600V is bang on the money.  If the diaphragm were to touch the stators (or rather if it were loose enough to do so) then the distortion would be easy to hear.  Open any Stax driver and the diaphragm is tight as a drum for this very reason. 

 

[chinsettawong]

Quote:

0.5mm and 600V is bang on the money.  If the diaphragm were to touch the stators (or rather if it were loose enough to do so) then the distortion would be easy to hear.  Open any Stax driver and the diaphragm is tight as a drum for this very reason.
 

Hi Spritzer,
 
I know what you mean.  I don't think I have a problem with diaphragms touching stators.  If that happens, it's very obvious.  I'll report back after I have a chance to listen to them again tomorrow.
 
Wachara C.