Tachikoma

Tyll made a second measurement of the 009 because Spritzer gave him a KGSS to use as a reference, not because he had two different 009s. The measurements are also almost identical. The two links you meant to post are: http://www.innerfidelity.com/content/more-stax-measurements-sr-009-sr-007-sr-507-sr-404-ltd-sr-404-and-sr-003 http://www.innerfidelity.com/content/stax-mafia-makes-unrefusable-offer-and-i-begin-electrostatic-headphone-measurement-program

In a way that is similar to what happens when I unplug a fan etc. I think its just that my source is more sensitive to it than other things. Upon closer inspection, it sounds like its just one channel whose levels are fluctuating... I'm going to see if putting the spacer on the other side of the diaphragm does anything. Update: Found the problem, its the bias connection.

Hmmm.... I'm having an odd issue with these Gamma pro drivers I'm trying to repair, the balance is randomly swaying between left and right when running on pro bias (had some swaying at normal bias too, but it stops after a while). Could it be that I have assembled the drivers wrong and the drivers are drawing more current off the bias than they should? I also noticed that plugging these phones in causes mini brown-outs for my DAC/usb converter too.

Any chance the membrane simply got stuck on the stators (to the point it doesn't come off after you ground it)? This, combined with the bass suckout you mentioned sounds exactly like my experience with a membrane that I coated with too much antistatic. Its also consistent with Wachara's observation that Stax increased the spacer thickness slightly, which might be to address this very issue.

Nope, but on high bias, any dust in the drivers makes a great deal more noise. If you don't mind taking the drivers apart, you could clean the stators with sticky tape and very carefully blow any dust on the membrane off.

Surely a bass suck out would show up on FR measurements though? Do you think its just your pair or 009s in general?

Any idea who this guy is? http://www.head-fi.org/t/711706/ic-kgsshv

This bit maybe? I did wonder whether this was possible on Violectric's amps when I saw similar-ish voltage swing specs. max. output voltage 80V

I had a short A/B between my DAC-2000 and a marantz SA-11, and I think it held its own. The DAC-2000 lost the shootout 2 to 1 but there really wasn't much between the two. Having said that, if I were to spend $600-800 on a new DAC, I'd probably spend it on something else. Maybe an audio-gd thingy.

I'll get that bias board you sent me shoved in at some point, when the electronics workshop people find the time for it. Not doing it myself because I'm not confident that I can do mains wiring safely.

Well, got it for less than $1k several years ago Pretty sure the O2s can handle something like 1K Vpp anyway, and with the ~200V bias its unlikely to blow up that easily. All transformer solutions have the potential to destroy headphones, by that logic.

Can't be sure since my multimeter probably doesn't have a high enough impedance. I'm reading 122V on the Fluke 75. The date on the box says it was manufactured in 78. Guess I'll look elsewhere for my "semi-decent" transformer solution.

Ok, 5Vpp on the input tuns into ~250Vpp, so its a 1:50 transformer :0

Ill-suited in the sense that I'm not going to get amazing results out of it. Its not different from the SRD-7 direct wire mod as far as I can tell. The multimeter indicates that the amp isn't putting out ridiculous 100V spikes or anything like that. The overload kicks in around ~14Vpp

So... I've found that the ECA-80 transformer box has overload protection circuitry built-in, and it kicks in far too easily when I'm trying to drive my O2. I want to direct wire the audio transformers to bypass that, but I've found that it has 4 input wires on each transformer; since each transformer drives one channel, two of these should correspond to the positive and negative audio inputs, but what would the other two inputs do? I'm under no illusion that these transformers are even remotely suited to the task, they aren't any larger than those in the SRD-7. Picture: http://i.imgur.com/XZ5nkyT.jpg

Hee, hope so. Will be trying to drive the O2 with the Sony transformer box and Spritzer's bias board (bye bye T1S).

A Pioneer M-22, sorry.

Woohoo, got a dealer demo set from YJ that allegedly has less than 200 hours on it. Shipping is going to be massively pricey though...

I've opened up a few Sometimes I can see it from the outside as well. I remember experimenting with one particular pair of drivers that had an imbalance, with the weaker side taking time to build up some charge, I don't think swapping the diaphragms between the drivers made any difference.

Has anyone else encountered signifcant amounts of corrosion on electrostatic stators? I've been wondering whether it would be worth it to disassemble it and scrape that shit off. The drivers with corroded stators always take a while to charge up; having said that its usually ok after I give it enough time to do that.

If they had the budget for a $100K headphone, sure.

Its in principle an electrostatic, isn't it?

Spritzer, do you still have any stax bias boards lying around? I'm thinking of getting a 580V bias hacked onto it. My other pro headphones are sensitive enough to run off the ECA-80's stock bias, but the O2 is a totally different story.

Sounds reasonable. If only they built the headphones to the same level, because everything about it stinks of planned obsolescence, from the cable to the headband. Thank goodness that the drivers are alright, besides needing a little charge time to reach full volume on one side.

Sony ECA-80 internals, as requested: http://imgur.com/a/J0CcD I wonder why there are condoms on two of the caps in the corner...