[number1sixerfan]

Problem Solved! It was the EL34 tubes (they wear out) on the Woo WES. Woo provided very good help with troubleshooting and suggested an awesome replacement to their stock EL34 tubes. The new PSVANE tubes provide a new experience. They make the SR-009 not as bright and they seem to show more nuances. Long story short.....the STAX SR009 were not to blame!

Woo's customer service is impeccable. I've had quite a few of their products over the years and they're just so helpful. And the best at email correspondence out there.

 

[ThibSan]

Just a note to inform that I had to drop my 009s (not 009) to the shop today because of channel imbalance issue (left channel is super quiet).

This occurred after a serious raise in humidity due to storm, maybe this is just a coincidence. I owned the pair for just over two years, I always keep them under their stax cover and on the stax wood stand.

Maybe an interesting point for others facing similar issues: when the amp is off, applying a gentle pressure on both side of the headphone does not suggest any difference in between left and right. When the amp was on the "stax fart" is also imbalanced (without any music playing). This may help those who do not have two amps at home to rule out where the problem is coming from (e.g. tube vs headphones).

Hopefully the distributor will be able to check is this is a wire issue or something else like dust or humidity prior to sending them back to Japan.

 

[AudioCats]

was the 009 discharged when not in use? (touching the pins with finger, or better yet, use a piece of conductive foam)

 

[Julez]

was the 009 discharged when not in use? (touching the pins with finger, or better yet, use a piece of conductive foam)

I always wonder about questions like that. If it's not a problem with the cable (broken cable or loose wires) it means that at least one driver is defective. Imbalance occurs in my experience only when the coating is damaged (sometimes combined with a hole in the membrane). Normally it's a dust issue. Also high humidity can cause problems especially with the 009 and 009s as their membrane stator gap is 0.45mm wich is less that the 0.5mm of the Lambda headphones or the 007 series. High humidity would cause a lower breakdown voltage of the insulating air between membrane and stator because of the smaller gap. If the insulating barrier of the air is overpowered it will result in sparks between membrane and stator wich will burn the coating and can cause holes in the mebrane (the same is true for dust wich also deceases the gap between membrane and stator).
The membranes will lose it's charge no matter if you discharge it actively or leave it plugged in (if the amp is turned off of corse) or unplugged. Otherwise there would be no need for a bias connection wich keeps the membrane charged. If you cut the bias connection during playback the headphone will go down in volume and stop playing after a while because the charge has dissipated.

 

[AudioCats]

...
The membranes will lose it's charge no matter if you discharge it actively or leave it plugged in (if the amp is turned off of corse) or unplugged. Otherwise there would be no need for a bias connection wich keeps the membrane charged.

the diaphragm can hold charge for a very long time, if the humidity is low.
ESP950 is very prone to developing the channel imbalance issue, the one method to keep it at bay is to always plug the pins into a piece of conductive foam when the phone is not used. (or, if using original E90 amp, keep the phone plugged in the E90)

If you cut the bias connection during playback the headphone will go down in volume and stop playing after a while because the charge has dissipated.

how did you disconnect the bias ? (most people don't have access to the bias lines)

 

[ThibSan]

was the 009 discharged when not in use? (touching the pins with finger, or better yet, use a piece of conductive foam)

Never though of this. I was under the impression that placing them on their stand with the dust cover was enough of a ceremonial.
A 5k headphones dying like that is really not reassuring, with the BHSE it makes it >10k of very pretty, but useless, gear on the shelf

@Julez do you see this often or am I just unlucky?

 

[Julez]

@Julez do you see this often or am I just unlucky?

I get about 5-10 SR-009 every year (wich is just a fraction of the faulty 009s). If you think the serial numbers a correlated to the ammount of units sold it's not a high number. I also never got a SR-009S. But normally the first two years new headphones are under warranty (at least in the EU). So people send them to the shop or distributor. I don't think it's nescessary to treat the headphones different from other expensive headphones and if there is a fault it was already there when Stax shipped the headphone to the distributor. Only a fraction of the defective 009s had a tear in the dust cover (presumably caused by plump hair) but all defective units without such a tear had a faulty coating wich was immediatedly visible to the naked eye after opening the drivers.

 

[ThibSan]

Just to report that my 009s are back home!
It seems we had “bad luck” with these ones as it is the first pair of 009s returned to the importer with this type of problem. The importer ordered parts from Japan and made the repairs locally.

The cherry on the cake was the replacement made free of charge, even if this happened after the warranty expired.

Another good reason for working with local dealers and importers.

 

[knokki]

Yes ,Still working fine.
I suspect the dust on the dust covers create some static effect that screws up the treble info. I now keep my sr009 in a bag to keep the dust out.

I just want to acknowledge here that I used the trick of John Heng (treating the diaphragms with moist) with a SR-507 with a severe channel imbalance and I was able to cure the problem which slapping the enclosures did not cure. The left channel did not do much before the 'cleaning job' and after cleaning the right ear was slightly lower in volume, so I did that one as well. Having scalped a few Lambada's I wonder whether the newer types are more prone to channel imbalance as the diaphragms and stators do not seem to be sealed with the dust covers into one unit as is the case with the older models (Lambda Pro, Lambda Signature, Lambda 404, Lambda 404 LE). I used a piece of moistened, soft toilet paper to wipe cq clean the diaphragm and a kleenex to dry it, without taking extreme care. Problem solved.

 

[Hubert481]

Do you habe a link to the trick?

 

[knokki]

Dear All, I recently purchased an SR009 (s/no 3599) few months back. After enjoying listening to its incredible sound for a few months, the sound on the left driver, particularly the left treble start to fade and the volume was lower than my right side. I found out on this forum that many are experiencing the same imbalance problem. I swap amps and swap with my older Lamda pro and the problem indeed stem from the Sr009 headphone itself.

Now, I own a pair of Martin Logan Ethos which are electrostatics also. And they suffer a similar problem after prolong use with the fading of the treble and channel imbalance. On their forum, the solution is to give the membranes a light wash ( yes...wash with water).

I thought the SR009 was also suffering the same problem. Though the membrane may be thinner.
I carefully removed the fabric cover over the pad, then undid the 6 small philips screws holding the ear pad using a spectacle screw driver set.

Once ear pad is removed, you will see a black circular metal mesh and O ring. Very carefully lift the O ring and metal mesh up and out. The super thin membrane is just underneath and now exposed. Be super careful not to touch the membrane. I use a glass of water, then use a drinking straw, put straw into the clean water, then block the top end of straw with my index finger. I then carry the straw over the membrane ( 1or 2 inches) above. Then releasing my index finger, a few drops of water are release and flow over the thin membrane. You can tilt the driver at an angle so that the water can run off. Make sure water runs off away from the wires. Do a few times on the membrane to wash the whole surface. Then the other side.The other side just have to drop the water through the grating onto the membrane.

Once you are satisfied that the membrane is decently clean ( shine bright light on the membrane and look under magnification), I use a hair dryer in cold air low speed setting to just gently blow the large bubbles of water away. My hair dryer is blowing about 2 feet away to ensure no hard blowing.

Can also soak up any leftover large droplets of water left on the membrane with the edge of a tissue. Be super careful not to touch the membrane itself.

Once pretty dry, ( there may be other smaller water droplets) left behind is ok.

Now super carefully put back the metal mesh and O ring, then screw back the ear pad but do not insert the fabric cover back yet.

To properly dry the SR009, I place the SR009 in a large seal plastic box with a large box of drying agent ( you can get from supermarket those you place amongst clothes to stop mould growth e.g. thirsty hippo). I close the plastic box with the SR009 and drying agent inside for 2 days to allow the drying agent to thoroughly dry the SR009. After two days or so, check the membrane surface is thoroughly dry with no hint of water droplets.

Now replace back the fabric protector.

I fire up my SR009 and the sound is back to original and balance. Treble back to normal. So fluent and delicate. Volume back to normal.

I find that just trying to blow away dust off the membrane with a blower does not work. It must be water. If the water in your area is not clean or hard, then use bottle water.

Very happy with the result.

Now I keep my SR009 in a plastic box with drying agent and away from dust.
If you need further guidance, you can email me direct on mkhheng@gmail.com.

I am a mechanical/mechatronics engineering Snr lecturer from Nanyang Tecnological Uni, Singapore.

Hope my posting helps those suffering this same issue. There is actually nothing really to spoil in the headphone itself. That is why Stax can return the headphone without detecting any fault. Is just dirty membranes.

This is the 'link'

 

[Hubert481]

Great - haha, i have also the Ethos

 

[knokki]

Did a 404 Limited Edition with a severe channel imbalance today. Taking the sealed driver apart is no fun as is assembling it again (I used a glue pistol), but a water wash did the trick again. Thank you, John Heng