Stax SR-009 Channel Imbalance Trouble / Driver Problem?

[Gu Sensei]

Quote:

One Thai Head-fi Senior member suggested that the channel imbalance can be caused by the Stax Farting,
can that be the case here?
The first Thai SR009 have the same problem and they can solve that.
 

 
Hmm... that was interesting. While wearing the phones, I just put my fingers around the outside of the right ear cup and gave a gentle push forcing air through the back of the driver. A nice clear signal with no imbalance was the result. It seems quite stable so far. Could it be that simple? What is happening to make that effective, anyone have an idea?

 

[arnaud]

Humm, I had presumed the center hole could be to increase clearance so that the membrane does not in contact with the stators during large displacements. I wonder if it might be exactly its function given the diaphragm can so easily pushed toward the stator.

This might be due to a thinner spacer than 007 and / or larger diaphragm diameter and / or thinner i.e more flexible diaphragm?

As for not causing it to happen again, maybe be very careful not pushing the earcup too strongly toward the head / doing it slowly because there's no vent?

 

[edstrelow]

Wow! Sorry guys but I am glad that someone else is a first adopter here.  The 009 is looking like an overbright phone, with  quirky operating characteristics or a basic design defect, like the original Omega. At  this point, if I had $5K to invest in my set-up it would probably go into an amp or source rather than these phones. 

 

[spritzer]

The diaphragm can't be pushed unless you exert a lot more force on it than is at hand here.  The dust covers can be moved but the diaphragm is essentially a static object and tight as a drum.  As for why the sound changes, I'm sure it is a just a loose connection.  Who is the first one to open up a set so we can see what is going on? 

 

[jgazal]

[size=10.0pt]Is it possible that the aluminum ear cup becomes electrostatically charged? I thought it has some kind of isolation layer (for instance, anodizing).[/size]
 
[size=10.0pt]A touch would discharge the ear cup?[/size]
 
[size=10.0pt]When I said about earth, I thought it would be nice to have a route to earth then touching everything to get rid of parasitic charges.[/size]
 
[size=10.0pt]I know the amplifier case, although connected to ground pin, remains isolated. And I know that neutral pin also connects to earth (but this one just by the circuit).[/size]
 
[size=10.0pt]I do not see an escape route for the ear cup.[/size]
 
[size=10.0pt]Someone said once that the diaphragm parasitic charge fades away naturally. It could happen with the ear-cup also.[/size]
 
[size=10.0pt]I wonder how the leather friction the ear cup, listener dressing wool, the dry weather and a room with carpet charges everything (including ear cup). Maybe this is a paltry charge.[/size]
 
I am not a smart guy, but have I said something very wrong?
 
Anyway, please be patient with me to explain where I am failing. 

 

[edstrelow]

Quote:

[size=10pt]Is it possible that the aluminum ear cup becomes electrostatically charged? I thought it has some kind of isolation layer (for instance, anodizing).[/size]
 
[size=10pt]A touch would discharge the ear cup?[/size]
 
[size=10pt]When I said about earth, I thought it would be nice to have a route to earth then touching everything to get rid of parasitic charges.[/size]
 
[size=10pt]I know the amplifier case, although connected to ground pin, remains isolated. And I know that neutral pin also connects to earth (but this one just by the circuit).[/size]
 
[size=10pt]I do not see an escape route for the ear cup.[/size]
 
[size=10pt]Someone said once that the diaphragm parasitic charge fades away naturally. It could happen with the ear-cup also.[/size]
 
[size=10pt]I wonder how the leather friction the ear cup, listener dressing wool, the dry weather and a room with carpet charges everything (including ear cup). Maybe this is a paltry charge.[/size]
 
I am not a smart guy, but have I said something very wrong?
 
Anyway, please be patient with me to explain where I am failing. 

I guess its possible that there could be a charge in the earcups affecting the drivers but the two are normally isolated electrically by insulation.  Also the Lambdas are pretty much all plastic except for the backing plate which might be aluminum.  If i remember rightly, the electrostatic force falls off rapidly with distance,  the square of distance? so charges some distance from the drivers would have little impact.
 

 

[Gu Sensei]

They were out of whack again and it took a little more effort to get them right. However, it is all balanced right now. I am looking into options for a replacement pair or a repair with the store where I bought them. Fantastic sound when all is right.
 

 

[kiertijai]

Dear Gusensei,  So is it the Stax farting that has caused the problem or other cause of
channel imbalance?

 

[Gu Sensei]

I have no idea what is causing the problem. Spritzer's suggestion of 'a loose connection' seems to ring most true considering I occasionally can affect the sound by moving the cable about. It certainly worked the time I pushed down evenly on the frame but I am sure I moved the cable at the same time. Everything is has been quite stable for a while now though.
Quote:

Dear Gusensei,  So is it the Stax farting that has caused the problem or other cause of
channel imbalance?

 

 

[jgazal]

Quote:

I guess its possible that there could be a charge in the earcups affecting the drivers but the two are normally isolated electrically by insulation.  Also the Lambdas are pretty much all plastic except for the backing plate which might be aluminum.  If i remember rightly, the electrostatic force falls off rapidly with distance,  the square of distance? so charges some distance from the drivers would have little impact.
 

 

[size=11.0pt]Thank you. [/size]
 
[size=11.0pt]It seems a loose connection, humidity condensation, dilation or contraction due to temperature variations in transport are more reasonable explanations, in that order. [/size]
 
[size=11.0pt]I think it’s time to keep my mouth shut. [/size]

 

 

[visualguy]

 
Quote:

They were out of whack again and it took a little more effort to get them right. However, it is all balanced right now. I am looking into options for a replacement pair or a repair with the store where I bought them. Fantastic sound when all is right.
 

Have you tried talking to Stax directly about this problem with the SR-009? Has the store tried talking to Stax?
 

 

[ricmiclaw]

I have an SR-009 on order through Woo Audio in New York and received the following e-mail from Jack earlier today:

"We received a news from STAX. About 12% of SR-009 developed noises due to microscopic dust between the stator and the film. A decision made by June 27th that all shipments are stopped. STAX is currently revising the design and solving the problem. Shipment will resume within 60 days.
 
I am sorry for the bad news. I will keep you updated.
 
Sincerely,
Jack"

I don't understand the date reference but the rest is crystal clear.
 

 

[kiertijai]

Are there any recommendations for those who already have the Sr009.
Should we continue using that?  What is the adequate storage to prevent
micordust?  Any preventive measure?   Any warning sign that we have to
be concerned.?
Will Stax replace the defective batch?

 

[ast]

Quote:

I have an SR-009 on order through Woo Audio in New York and received the following e-mail from Jack earlier today:

"We received a news from STAX. About 12% of SR-009 developed noises due to microscopic dust between the stator and the film. A decision made by June 27th that all shipments are stopped. STAX is currently revising the design and solving the problem. Shipment will resume within 60 days.
 
I am sorry for the bad news. I will keep you updated.
 
Sincerely,
Jack"

I don't understand the date reference but the rest is crystal clear.
 

 
That must be a typo -- it might really mean May 27th.   
 
Bad and good news for all those placed preorders ...
 
 
...
 

 

[chinsettawong]

Is it possible that the diaphragm has randomly collapsed to one side of the stators? 
 
Wachara C.