The Headcase Stax thread

[spritzer]

The single tube seems to be similar BS as the Woo WES phase splitter.  High noise and barely works. 

Those Stax emblems look like they were pulled off headphone stands...

[kevin gilmore]

I did wonder where they got those emblems. The stands would be the cheapest way possible. That transformer box has got to be stupid expensive.

At least some of the smaller 9 pin dual triode tubes have a shield that you can tie to ground to prevent crosstalk. not enough pins on an octal to do that.

Edited September 8, 2017 by kevin gilmore

[JimL]

Actually, he says the transformers are from the Stax F81X electrostatic loudspeakers.  As to why a transformer designed to sit between a power amp with a couple ohms or less impedance and a large capacitative load (the F81) would be a good choice for a 6336A tube output with a couple hundred ohms plate impedance driving a small capacitative load of around 100 pf...?.

Edited September 8, 2017 by JimL

[spritzer]

Don't go dragging logic into this!!    These are musical instruments!!!!!

[wink]

[gepardcv]

I started getting a rattle in the right channel of an SR-207. It's only audible in lower frequencies, like the bass shaker test on Audio Check. When the same thing happened to my HD600, I disassembled it and removed a hair from the driver, which fixed the problem. A little searching the threads here hasn't turned up disassembly instructions for Lambda-type headphones. Repair suggestions, please?

[sorenb]

42 minutes ago, gepardcv said:

I started getting a rattle in the right channel of an SR-207. It's only audible in lower frequencies, like the bass shaker test on Audio Check. When the same thing happened to my HD600, I disassembled it and removed a hair from the driver, which fixed the problem. A little searching the threads here hasn't turned up disassembly instructions for Lambda-type headphones. Repair suggestions, please?

remove the house from headband assembly, be careful not to bend the plastic as it is kind of brittle.
there are four small Philips-screws, located in each corner beneath the pad - you don't have to remove the pad, just push/lift it a bit in the corners and loosen up the four screws.
Afterwards you can remove the pad + baffle inlucing driver from the housing.

[gepardcv]

Thanks, @sorenb! That was exactly what I needed. I think I have it sorted out now. Didn't find any hair or dust, but just disassembling and reassembling the cup down to the driver helped for some reason. 

[mtaifa]

I've started tearing into the KGSShitbox and noticed some differences from the earlier version.
R9-R12 are 560R on my version, 2.2K in older rev.
R40 + R47 are 1.46K on mine, seems to be 500K on original.

See pic:
https://i.imgur.com/MgNuP0N.jpg

Should I change some of these?

[Ali-Pacha]

Got my hands on some late SR-1. Interesting mid-centric / hollow sound, but all around impressed by how it's close to the later iterations of the concept (SR-3, SR-5...).

Ali

[spritzer]

The input on that KGSS is so fucked that it might be better to just take the pot off the board and just wire it all from the beginning.  You should have a 100R input resistor and 500K shunt to ground.  That's it...

12 minutes ago, Ali-Pacha said:

Got my hands on some late SR-1. Interesting mid-centric / hollow sound, but all around impressed by how it's close to the later iterations of the concept (SR-3, SR-5...).

Ali

Be sure to replace the adhesive rings in front of the drivers or they will sound pretty wonky...   

[Ali-Pacha]

You mean the adhesive thing which sticks the drivers to the cups (I've that on my SR-5) ? Any picture welcome, before I open them up  BTW, they don't sound off to me, just something different.

Ali

Edited September 23, 2017 by Ali-Pacha

[spritzer]

Yes, the drivers were glued to the baffle on all my sets.  No pics as I didn't take any but as soon as you open them up there should be a very dried out adhesive ring. 

[mtaifa]

19 hours ago, spritzer said:

The input on that KGSS is so fucked that it might be better to just take the pot off the board and just wire it all from the beginning.  You should have a 100R input resistor and 500K shunt to ground.  That's it...

 

Thanks!
I already removed the pot and will be installing off board pot. I will also remove the 4 small caps, C10 and C11 (+C7 and C16)

 

[johnwmclean]

So I get my new Stat SR-007A’s today from eBay and the box serial number reads SZ2......  Back to Japan they go. 

[judo]

Why, the newest what I heard about were sz2 or there is a new version or new serial system?

[johnwmclean]

I believe the SZ3’s are the newest since ~2015.... the diaphragm was slightly tweaked.

[judo]

The lasts from PJ were SZ2, mine is for example.I bought from there because I wanted the new diaphragm too. I do not know this is true or not, PEEK or mylar, etc... Spritzer always tells there is no real system in the serials.

Edited September 25, 2017 by judo

[MLA]

Can check mine when I get home. Bought them a little less than a year ago in Tokyo.

[johnwmclean]

Thanks guys. After a read here and there I count myself more clueless than I originally was, I presumed the latest version was the SZ3 but as Spritzer says the serials are all over the shop and the SZ2 version I have may be new production.

[spritzer]

Stax and serial numbers mean nothing so it could very well have been brand new.  The first Mk2's were SZ2 but there were reports of SZ3 in the mix as well.  The new ones should be SZ3 but who knows what they are up to now. 

[MLA]

Well, just checked mine and they are SZ2 - 2253.

I purchased them on site in Tokyo in November last year from a music store. They were not in stock at the store, so these were delivered straight from Stax the next day.

Unless someone kept yours in storage for a couple of years before selling, I'd assume it's new stock. 

[johnwmclean]

Thanks guys that’s a relief, my serial is SZ2 - 2301, the box is minty fresh and headphones are immaculate, they sound darn good too...  

[justreadingup]

I purchased my 007Mk2 from HeadAmp +/-  a year ago and the serial# is SZ3. As mentioned, these #'s seem to be all over the place, and all I know is mine sound fine. They're  black in color for the U.S. compared to silver models from Japan, though.

[joehpj]

I believe SZ2 are 007A while SZ3 are 007mk2. (domestic / international version). All of my friends' 007A no matter manufacturing time are SZ2.

Edited September 26, 2017 by joehpj