[chinsettawong]

Are you sure that Stax coats the diaphragm on both side? I once open up a SR207. After a close investigation, I'm pretty sure that it's coated only on one side.

 

[Julez]

I thought so. At least on the older models. But the coating on the newer Lambdas is really thin so it is hard to see. Maby I will
try to measure the coating resistance on a Lambda driver from a LNB and see if it is coated on both sides. Maybe Stax is after
all only coating one side. I can see no real advantage to coat both sides. It can only cause more trouble than coating one side.
And after experiencing there is no difference at all in volume and frequencyresponse I will only coat one side from now on.

 

[Julez]

I thought I share that discovery so people can be shure that coating one side does work well without any differences to coating both sides.

 

[Julez]

Hi Wachara,
 
you are right. I just measured a 507 driver on both sides but could only get a result under 2 gigaohm on one side. I had to measure
less than one cm of coating to get a reading of 1.8 gigaohm. So the resistance of the 507 driver is pretty high. I heard a few times
Stax uses coating with about 200-500 megaohm. On my measured driver this is not true. I would say resistance is about 2.5 gigaohm
per cm. The coating is so thinn that it is not really possible to see the coating. So Stax seems also to only coat one side. At least
on the Lambdas.
 
I thought otherwise as I experienced if the contact between the two membrane rings on a 007 has failed it will be down 6dB on that side.
Soldering a bridge between the two rings immediatly solved the problem. I had this with two 007s. I thought this is due to only appling
the bias to one side of the membrane. But this can't be as it does not make any difference if one or both sides are coated.
 
I also experienced if only one side is coated with about 200-400 megaohm the membrane will glue to one stator if I push the heaphone
towards my ear. I recoated with a solution where I doubled the solvant (pure alcohol) and now the membrane will not glue to a stator if I
push the driver towards my ear. So if you use an antistatic like my Kontakt Chemie Antistatik 100 (it's a spray) you should make a thinn
solution of the antistatic with a solvant and you apply it very thinn. I allways put a lot of the solution on the membrane and then turn the
driver 90° to let the unneeded coating drip back into the bottle of my coating mixture. I do this in a selfmade dustfree flowbox and I filter
the coating through a fiber filter with about 100micrometer holes. If you barely see the coating after it has dried completely it should be
good. Best to measure the resistance with a proper measuring instrument (wich can be bought for about 30USD). Then normally it is
working as it should and there is no dustproblem since I do this method of coating the membrane. But I use this only since a few days.
Let's see if the coating stays stable for a longer period.

 

[chinsettawong]

I have been using the floor cleaner I recommended for the past few years and I have no problem with it so far.  I can coat it extremely thin too.  In fact after the coating is dried and buff the diaphragm and the diaphragm is crystal clear with no trace of coating to be seen.  I think that's what a good coating should give.

 

[Julez]

Yes that supports defenitly what I also found out. The coating must be very thin so it is really hard to see. Than one gets the needed surface resistance. I just had problems when I tried to apply the coating with a sponge as somehow allways some prticles (of the sponge or what was in the sponge) ended up being baked into the coating making that ugly tone indicating a dustproblem. Rubbing that off with a very soft brush often destroyed the coating and led to up to 10dB less output on that driver.

 

[-JFK-]

Someone have try to spay the coating and let it dry?
In that way, we don't need to touch the diaphragm so no dust transfer, and it "should be" applied really homogeneous.

 

[chinsettawong]

This is what my coated diaphragm looks like.
 

 
I put my coating on using a lint free cloth (microfiber?) and buff out after it's dried.  Then, I check for the dust by looking at the diaphragm from the side, and I use the cloth again to clean away all the small particles.  

 

[Julez]

Looks like no coating. I think that is ideal. Where I live (Düsseldorf) it is pretty dusty. I think that is the reason why I have to do this in a dustfree box.

 

[gaetan8888]

Hello
 
I've buy a graphite tube, how can I do a very thin coating with graphite ?
 
I would use hostaphan plastic film.
 
Thank
 
Bye
 
Gaetan

 

[-JFK-]

Hello

I've buy a graphite tube, how can I do a very thin coating with graphite ?

I would use hostaphan plastic film.

Thank

Bye

Gaetan

Hello,

Many people report that antistatic solution work very well and it's easy to use...
Why do you want to use graphite?
Well, you can try a highly diluted solution of cement glue mixed with graphite and try to spay it?

 

[-JFK-]

Hello,

Did someone can post a link about the dust screen that you use?
Or it's the same mylar film randomly wrapped (crumpled) ?
Thabk you.

 

[Julez]

You can use the same film you use for the membrane. Just crumple it very tight so it wil be a small ballthat is  very compressed. Than you carefully have to unwrap it. After that you can use it as dustcover. Strechtch it lightly (so it will not flutter when pushed by the air of the driver) and glue it on top of the driver (or wherever you want it to be glued to). 

 

[OnyxOcelot]

Slightly off topic but I am curious to head how people make the headphone bands.  So far, I've only used parts of old headphones, but would like to make my own.  I have access to a small sheet metal brake (a type meant for making the chassis of electronic devices), but nothing else in terms of metal working tools.  So, here are my questions:
 
What type of metal do you use for your headphone bands?  Spring steel? 
 
Do you hot or cold bend these metals?
 
Any tips on metal bending techniques would be appreciated.

 

[chinsettawong]

The material use is actually up to your creativity.  As for my latest JF Clone, I use brass welding rods and hand bend to shape.  The back plates that hold the rods are 3d printed.