The Headcase Stax thread

[Tachikoma]

The dust covers should have no effect on the channel balance. There is the possibility that you didn't reassemble the drivers perfectly (say, something was at a slight angle), which will cause an imbalance, so just pull the weaker channel apart and put it back together again. If that doesn't work... maybe flip the diaphragm around, it _might_ make a difference if its only coated on one side.

[nopants]

I'm not sure you can flip the 007 driver, but if someone can show otherwise I'm down to try anything.

figured I'd contribute something as long as I'm complaining, here's a shot of the 70761 driver (my working pair):

there are six screws to hold down the grill compared to the four in the 70111 driver. the resin? frame edges angles upward, away from the dust cover on the side which faces the ear. There's a small piece of plastic which covers the cable housing and strain relief- the two extra screw holes affix this floating piece to the driver frame.

in the 70111 driver the resin frame is uniformly flat and from what i can tell the dust cover seems to sit much closer to the stators. the resin is also one contiguous piece. will update with a picture when I feel like tackling the imbalance again. the sound between the two is markedly different but I'm not sure how fucked up the 70111 drivers are.

oh well at least they were obtained through a trade for the lcd2s...

[Dusty Chalk]

General question:  is plastic a good substance to be used in the manufacture of electrostatic headphones, what with their being staticky and lint magnets and all?

[chinsettawong]

To check for imbalance I would check the wires and their connections first.  Then if the problem still persists, I would recoat the diaphragm.

[spritzer]

That driver is a bit of an odd duck, a cross between the first version and the look we have to this day.  If you took out the diaphragm then you have to make sure that no spacers were moved out of place or that the diaphragm went back in the same way.  If not then you will have problems. 

 

As for plastics and electrostatics,  some are just fine but others aren't really suitable. 

[Laowei]

Another data point.....

After a half hour listening to my newish SR-009s last night, I started to get a channel imbalance. The left channel was slightly lower, maybe 2-3dB. I tried the Spritizer Thump, but that was unsuccessful in restoring.

With the amp playing and the headphones on I pulled the cable jack out of my amp, touched the pins with my finger and reinserted. The left channel was now immediately restored. A while later I noticed a slight bit of static in the left channel that was not in the same place when repeating the track. I wiggled the tubes in their sockets and taking off the headphones, I cranked the volume control back and forth a few times. The cans played fine after that.

I had not experienced either problem previously in the month and a half I have had the cans.

Originally I broke in my KGST with an unmatched quad of Philips branded 6S4As, and only recently replaced with a matched quad of GEs and readjusted balance and offset. I'll try reswapping tubes and see if the problem repeats. Also, I'll clean all connections, and double check all solder joints.

Edited November 26, 2014 by Laowei

[nopants]

If you took out the diaphragm then you have to make sure that no spacers were moved out of place or that the diaphragm went back in the same way. If not then you will have problems.

can you elaborate on how things should be aligned? i had half a mind to manually separate the drivers on each side on each side. how do you mess with the spacers?

in related news I managed to alter the other driver too so now it's balanced but fucked up haha

[dreamwhisper]

My kgss-hv has two holes to stick my headphone plugs in.
Both look very inviting... Do  you imagine she has a preference?

I sent a message to her last boyfriend (luvdunhill) because I'd rather not actually have to ask her.
I know she's a classy (class A) lady and I'd rather not offend her, just trying to get her turned on ASAP.

[dreamwhisper]

Nvm, just heard back from the seller, either plug is fine.
What a beast though, the 717 doesn't even compare.

[spritzer]

Another data point.....

After a half hour listening to my newish SR-009s last night, I started to get a channel imbalance. The left channel was slightly lower, maybe 2-3dB. I tried the Spritizer Thump, but that was unsuccessful in restoring.

With the amp playing and the headphones on I pulled the cable jack out of my amp, touched the pins with my finger and reinserted. The left channel was now immediately restored. A while later I noticed a slight bit of static in the left channel that was not in the same place when repeating the track. I wiggled the tubes in their sockets and taking off the headphones, I cranked the volume control back and forth a few times. The cans played fine after that.

I had not experienced either problem previously in the month and a half I have had the cans.

Originally I broke in my KGST with an unmatched quad of Philips branded 6S4As, and only recently replaced with a matched quad of GEs and readjusted balance and offset. I'll try reswapping tubes and see if the problem repeats. Also, I'll clean all connections, and double check all solder joints.

 

No way the amp is responsible for that, that was a diaphragm issue. 

 

can you elaborate on how things should be aligned? i had half a mind to manually separate the drivers on each side on each side. how do you mess with the spacers?

in related news I managed to alter the other driver too so now it's balanced but fucked up haha

 

Basically, the diaphragm has to go back in, exactly the way it came out of the driver.  That includes the spacers which Stax put there to perfectly align it. 

[Laowei]

Yeah Spritzer, I suspect there may be something amiss with the diaphram, but just checking everything to be sure to isolate the cause.

Listening again last night, the 009s twice developed a similar imbalance in the first hour. Shorting the jack pins with my fingertip again restored the left channel. Was then able to listen for several hours without a problem.

We have had some drastic weather changes here -record cold with freezing rain and snow to record highs of 70+ degrees and dry within two weeks. Maybe that is a contributor, I don't know....

ATM, it does not seem catastrophic, the imbalance issue is only a nuisance.

[nopants]

Basically, the diaphragm has to go back in, exactly the way it came out of the driver. That includes the spacers which Stax put there to perfectly align it.

I can't make out any spacers from disassembling the driver. Should I be looking for something specific? I replaced the aging adhesive around the cable entry with kapton, and tried to place the driver in as carefully as possible. I noticed some small defect in the back diaphragm but I assume I can't do much about this.

I was able to fix the majority of the balance by pulling a bit at the diaphragm with post-it while music was playing. it was easier to detect if I had aligned things properly by the resultant spl

[Tachikoma]

I can't make out any spacers from disassembling the driver. Should I be looking for something specific? I replaced the aging adhesive around the cable entry with kapton, and tried to place the driver in as carefully as possible. I noticed some small defect in the back diaphragm but I assume I can't do much about this.

I was able to fix the majority of the balance by pulling a bit at the diaphragm with post-it while music was playing. it was easier to detect if I had aligned things properly by the resultant spl

Err... that's the dust cover (and the "back diaphragm" is also a dust cover). There's only one diaphragm, and its in the middle of the driver, which you will not be able to touch with post it while its playing music lol. If you did find a small hole in the rear dust cover, try to patch it up with a very small piece of tape.

 

For reference, the diaphragm looks like this: http://tcengineering.files.wordpress.com/2014/01/img_2641.jpg

 

The stators are the metal plates that sandwich the diaphragm. These are the only parts I would touch with post it.

 

(http://tcengineering.wordpress.com/archive-of-projects/electrostatic-headphones/)

 

It really sounds like you haven't actually disassembled the driver, so why in the world are you having imbalance issues...

Edited November 28, 2014 by Tachikoma

[nopants]

sorry I only disassembled the headphones not the drivers specifically. I'm not too fluent when it comes to speaking headphones apparently

Edited November 28, 2014 by nopants

[spritzer]

That would be why you didn't see any spacers, they are inside the drivers. 

[DefQon]

http://www.aliexpress.com/item/Teflon-Chassis-Jack-for-Stax-Headphones/1386475435.html

 

Looks nice.

[spritzer]

50$ each with shipping isn't the best of deals.  Speaking of China though:

 

http://item.taobao.com/item.htm?spm=a230r.1.14.12.7ftFpD&id=42396278346&ns=1&abbucket=11#detail

 

http://item.taobao.com/item.htm?spm=a230r.1.14.245.7ftFpD&id=40220072535&ns=1&abbucket=11#detail

 

KGST and who knows what clusterfuck he's come up with for the new version... 

[dreamwhisper]

Is it saying they have 97 in stock?
What a confusing site.

[DefQon]

Yeh it sure is confusing. Was looking at that yesterday.

 

EDIT: I made a post about the imbalance in the mids with the assumption of thinking one of the electret drivers was failing "losing charge" in my AKG K340's in this thread little few pages back. Spritzer corrected me that there is no chance of an electret driver losing charge if stored for a long time in proper "storage conditions" (aka not under the sun or humid areas). If an imbalance has occurred and storage conditions were ok imbalance with an electret diaphragm can only be pointed to a physical connection problem.

 

I guess Birgir wasn't bullshitting me, I managed to test this with buying 2 more K340's from Japan and Germany. Both K340's had missing magic to the mids imbalance problems, as described by the sellers. Spritzer's hypothesis or personal experience confirmed true to what he said. 

 

K340 A from Germany had been stored away for almost 30 years, the seller being an old, retired gentleman didn't have any equipment left to test it so was sold as-is. 

K340 B from Japan had been stored away for god knows how long but obvious evidence of being stored under sunlight conditions (headband deteriorated to being sticky and earpads perished etc and more). 

 

So I opened up both 340's. K340 B's electret diaphragm was yellow in colour and had this hazy glaze to the shiny silver membrane, I accidentally poked it with my screwdriver and it made a hole crispy style. There was no way fixing it and from the obvious physical condition of being under the sunlight for all this time, I disposed it only keeping the dynamic driver, baffle's, screws and the plastic headband elastic holders and cups. 

 

Opened up K340 A and like my personal pair no obvious damage was seen. So I measured the resistors on the pcb, what should be 56kohm the imbalance side measured 232kohm's. Took both 56kohm resistors out and replaced it with some 62kohm 2w Kiwames, re-assembled headphone and aye presto! No missing upper mids on the imbalance side. 

 

So from what I experienced I went back to my personal pair, measured both resistors, both read 56kohm's. But there is more to a resistor then just it's specc'ed resistance rating, so out they went and in went some 62kohm Kiwames, while I was at it recabled internal wires to some pure silver solid core wires. Re-assembled and fuck me it worked. 

 

Initially while dicking around with K340 A I accidentally soldered in 560ohm resistors and that cut off any frequency above borderline mids, there was hardly any treble or highs or upper mids and lower treble, just bass from the dynamic driver and huge distortion if I turned the volume high. But it is odd the resistor bands read green, blue, brown and gold which is 560ohm's, measured them with my dmm after my findings and they were 56kohm's, fucking AKG cheeky bastards. 

 

So for those on the line of thinking TL:DR, my point is, if anything electret is stored away in ok conditions then an imbalance issue is most likely indeed a physical connection error. For those with K340's experiencing imbalance/missing in the upper mids may replace the resistors for the magic to come back. If your pair was under the sun for a long time, best dispose them.

Edited December 9, 2014 by DefQon

[spritzer]

Sun isn't the best friend of any plastic. 

[DefQon]

Nope it sure isn't. I would definitely like to find a way to restore all the SR-3/5's I have that are all yellow without resorting to using bleach. Tried it once and it did more damage then good. There should be a mild abrasive industrial cleaner that removes the outer yellow layer restoring like new finish to the plastic.

[wink]

How about a buffing wheel and some plastic buffing compound soap?

[livewire]

@ DQ - Is it ok to store my electrets under the refrigerator? So far, the outside of the box is a little dusty.

And what will happen if I don't have any Kiwamis? Will Dales work? Ultronix?

[wink]

Inside the freezer would work better, and it goes a small way toward cryo treatment.........

[livewire]

Ima concerned about freezer burn. I've got some fossilized waffles....