Well yes but one goes hand in hand with the other.  They are only there under fault situations though. 

Talk about crazy bidding, sort of surprised even for the rarest Stax around

 

http://www.ebay.com.au/itm/STAX-SR2-Electrostatic-Headphones-/221286604712

It was far off from my max bid...     I've seen two of these for sale in the last 10 years and it officially doesn't exist so price was no object... 

Yeah thats the first one I've seen I remember reading the old Stax thread where Carl had seen one go as well for about the same price range.

 

So you did win them? Nice..... (The 334 feedback person was me, hehe) but I really didn't expect them to go for so much, even more than the SR-1.

 

Let us know on how they sound.

Yup it was me and I'll post some pics.  Speaking of which, this just arrived yesterday...

 

 

This is a super rare, early SR-1.  Housing material is completely different from all the later versions and models, it is smaller and the earpads are supposed to be made out of foam like you can see in the early Stax ads.  Haven't tried them yet but I need to open them up first.  All that rubber is perished as can be seen on this unique plug:

 

 

Never seen one with screws and the full SATO Parts number on the front. 

 

 

Next to a SR-3 that I know was bought in 1971.  Still looks like new though...  Not the best picture but the SR-1 is a bit smaller, a whole lot lighter and the housing material flexes a bit. 

 

Good news is that the SR-1 housings are still sealed shut so they have never been tampered with.  If I had to venture a guess I'd date them from 1960-1962.  Condition is awesome for a 50 year old headphone... 

 

Also got one of these:

 

 

The first full size Stax transformer box which debuted in 1965.  Completely mint...   

Juste wrote something stupid...edited 

 

Ali

6S4A Mod of 007T

 

Following the nice high rez photos previously posted by Justin and Spritzer, I rewired my 007T (the first version from the 1990s with one normal bias and 2 pro bias).  Not only is the PCB annoyingly black, but it's also a bit different from the 007TII.  For example I did not see any Q15,Q16,Q17, or Q18.

 

It looks like a simple bit of wiring, but it took all damn afternoon what with troubleshooting and comparing pinouts and comparing to Justin and Spritzer's photos.

 

Anyway, I fired it up and the relay clicked and all 4 LEDs lit up.  I played around with TVR1,TVR2,TVR3, and TVR4, but if I'm not mistaken, after the mods, the adjustment process is different.

 

Should I adjust for balance and offset using the procedure for the 006T and adjusting only TVR1 and TVR2?

 

As it is now I get the following readings from the PRO jack:

 

Bias 277V

R+   6.3V

L+   4.5V

L-    54V

R-   -24V

 

 

Yes, now it just acts as 006t.  TVR3 and TVR4 could just be removed.  In fact you should connect to the other side of them. 

 

Do not connect anything to pin 1 on the tubes as that will cause problems. It's used inside the tube...  

 

Here is the last one I did showing the removed TVR3 and 4:

 

Yes, now it just acts as 006t.  TVR3 and TVR4 could just be removed.  In fact you should connect to the other side of them. 

 

Do not connect anything to pin 1 on the tubes as that will cause problems. It's used inside the tube...  

 

Here is the last one I did showing the removed TVR3 and 4:

 

Cool, thanks.  Just adjusted the balance and offset 006t style to +/- 1V.

 

Is there a sonic difference between connecting pin 9 directly to the lead of the plate resistor as you did above, versus connecting with one resistor in between as you did in the previously posted mod?

 

Here's a pic of Justin's mod below.  I copied his example and shorted pins 1 and 9.  I can't tell 100% but it looks like he initially cut the traces to pin 1 and then restored them with a solder bridge.  It also looks like he left all traces to pin 1 intact.  This really confused me.  I thought maybe he knew some details about the inner construction of the tube that made this logical.

 

In your old photo, it looks like you cut the traces to pin 1 and then wired pin 9 to the traces from 1 and 6... which makes sense.

 

Anyway, I'm probably making this sound way more complicated than it actually is.

 

I like the looks of your mod above, nice and simple.

 

So basically, I should cut the short between 1 and 9, isolate 1,  and use just one wire directly from 9 to the leg of the plate resistor.  Right?

 

 

 

I did just check some of my 6S4A's and none have a connection at pin one.  Still some versions might use that so better safe than sorry.  If the wrong part of the tube is connected there then the amp might go boom... 

 

That resistors is so small in value but since I will be removing the plate resistors in this one it was a good idea to do a direct connection.

I did just check some of my 6S4A's and none have a connection at pin one.  Still some versions might use that so better safe than sorry.  If the wrong part of the tube is connected there then the amp might go boom... 

 

 

 

Ahhh,  that makes sense.  I just checked pin 1 on the Raytheon 6S4A and pin 1 is not connected to anything.

 

Thanks.  And thanks to Kevin for introducing the mod many years ago.

just got my 009.... I can't say I'm 100% pleased....

The first thing I heard when I put them on was squealing... The exact same sound as those in ESP950... I was freaking out to say the least... I waited 4 and half months for it and spent quite a sum of money too..

So... I opened it up..

Guess what I  saw underneath the metal mesh cover? hair from cotton.... plenty of them.... I blew them off and the squealing is gone....

Come on STAX! I know you guys are packed with orders for 009, but really? The first thing I have do to after receiving it is cleaning it? WTF man....

Also... I thought 007's earpads are the antichrist... man was I wrong when I was trying to put the earpads for 009 back... do they really have to design it like this?

At least it wasn't ants that got into the driver housing.

 

Needless to say I'd probably be freaking out too if a headphone that cost that much squealed on me...

Guess what I  saw underneath the metal mesh cover? hair from cotton.... plenty of them.... I blew them off and the squealing is gone....

Really?!?!?  I thought the squealing was from too tight a seal (and movement).  I guess there are multiple causes.

 

Really?!?!?  I thought the squealing was from too tight a seal (and movement).  I guess there are multiple causes.

 

 

Think that one is the infamous Stax fart. 

Yes.  That is indeed what I meant.  That said, it was a rather high-pitched fart, hence my equating it to the squeal.  Are they different?

 

What's the theory here?  Distortion from unplanned vibrating items in the diaphragm?  Or does one think that it actually changes the capacitance or impedance or something and sends the amplifier into oscillation?  Or 'other'?

well...  please correct me if I'm wrong.. I thought that the fart is the diaphram hitting the stator and causing it to discharge or something like that....

I have experienced stax fart with both 007MK1 and 009 as well... 009 is nowhere as severe as 007MK1 in terms of that. With 009, I can still shake my head a little without the fart... With 007MK1, I had to stay very still because even moving the jaw could trigger one.....

The squealing... I don't exactly the reason, but I do know dust on the driver can cause that. In my case, because there was so much debris on my 009's driver, it became more like a consistent hissing with a little occasional squealing..

Anyway, it's just unacceptable how they let this set pass the QC because that hissing sound was LOUD; in fact, it's so loud that I can hear it even when my ear was 5 inches away from the driver (as I was lifting that side of the headphone to determine if the hissing was from an external source.)  

A quick google search returned me no other report of such problem... so I guess mine might have been the first one to have such a poor QC?

You were probably the first to take a peek inside

Hi Jwzhan,

 

Do they not have a dust cover on the back side?  Or do you open up the dust cover and find the hair trapped inside?

I didn't go that far into the headphone. I only took off the earpad and the metal mesh under the earpad. The bedris was just underneath the metal mesh and on top of the driver assembly (or whatever you call it.) If the cause of the problem are in the driver... I wouldn't dare to clean it myself...

It only took me 2 sec to blow off the debris, but it took me like 10min to take off and put back the earpad... There is no way that they could have missed it if they did any final inspection...

Now here is thought... maybe this is a refurb?  All those units sent in for repair from the US get replaced so they have to go somewhere. 

 

I opened up mine and it's pretty much the nightmare of the SR-Omega but made worse with screws.  The SR-007 pads are a joy compared to the 009... 

May very well be. I received it very late yesterday, so I wasn't in the mood of doing a full body inspection. After doing it just now, I found two scratched on the right cup.

I don't know what to make of it as of right now. Either their quality has gone down due to the inundation of orders for 009, or they are using refurb parts on new ones to save time... or maybe it's both.. anyway... it's bad.. (or is PJ selling at such a low price because they get refurb unit but not stating it? I certainly hope not. It's a bad business practice.)

I guess the only good news now is that it still sounds darn good with KGSSHV..

What serial number? That may indicate an older unit.

SN on the top sticker or the sticker under that?

I'm at work right now, so I don't have it with me, but I'm sure the serial number is in the lower 2000... around 2250? maybe 2257? have to check when I get home.

A quick search on google returned me serial number still in the mid 1000s during mid last year, so if it are an old unit, it must have not been that old. (if the serial numbers are consecutive and STAX didn't skip any... that means they have cranked out more than twice of units of their said annual production capacity. If this is an old stock... then they must have cranked out more than 3~4 times of their production capacity.)