The Headcase Stax thread

[spritzer]

LCD-2 pads would also work and the Denon pads too.  These are interesting:

 

https://www.mrspeakers.com/fostex-t50rp-headphone-accessories-comfort-upgrades?product_id=63

 

Fired up the SR-X Mk1 and they do sound quite nice.  Once they charged up with just a hint of imbalance there is plenty of bass along with the usual SR-X traits. 

[mypasswordis]

Awesome, those alpha pads may be just what I'm looking for! Not sure about the LCD2 pads since they're so angled and stiff. And very nice on the SR-X Mk1, an SR-X Mk3 with plenty of bass reminds me of an SR-X Pro which sounds very good indeed.

[spritzer]

First pics of the King Sound production models:

 

http://forum.doctorhead.ru/index.php?app=gallery&album=113

 

http://forum.doctorhead.ru/index.php?app=gallery&album=114

[shipsupt]

Looks like a typical 5 pin STAX pro-plug.  Birgir, can we rely on you to plug yours into a STAX amp to see if they blow up or not?

 

Moon Audio is saying August 1 now.

[spritzer]

They will be thoroughly tested and taken apart. 

[spritzer]

Looking at the pics, that socket looks a lot like the SATO socket Stax use. 

[livewire]

 

Moon Audio is saying August 1 now.

 

So, tomorrow then?

[skullguise]

At the NY spring meet, Drew said that - while the phones & amps operate on lower voltage - they should work out of Stax gear.  THINK he said Regular, but he may have also included Pro, outputs.....

[spritzer]

They will always work on a lower bias but going up can be tricky and cause a bunch of problems. 

 

It should be noted that Drew is pretty clueless about this stuff. 

[shipsupt]

Shipping notice received.  They are shipping.

[spritzer]

Turns out Drew wants to send Kevin a used unit from the Cali show.  What a fucktard and he's even going to charge full price. 

[kevin gilmore]

I paid for them months ago.

I am tired of waiting for the headphones.

I am tired of waiting for my 80 inch 4k full array LCD tv

And the server that goes with it

I am tired of waiting for my 2014 corvette C7 convertible

Getting too old for this

[spritzer]

Just get another Jag... you know you want to... 

[livewire]

Turns out Drew wants to send Kevin a used unit from the Cali show.  What a fucktard and he's even going to charge full price. 

 

The were not used (then). They were stuck in customs at that time.

 

EDIT: I was referring to the recent 7/20/13 Cali meet. 

 

There were two other recent Cali meets. One near Los Angeles in Newport Beach and another near San Francisco.

None reported that the King Sound was present at those meets. They did make a showing recently at a New York meet.

So yeah, there is a used set out there.

Edited August 2, 2013 by livewire

[kevin gilmore]

Just get another Jag... you know you want to... 

 

I think the newest version of the coupe (xkr-s) is one of the sexiest cars

I have ever seen. But I would never own one again. Not even as

my 5th car. Tata motors, you gotta be kidding.

Edited August 1, 2013 by kevin gilmore

[DefQon]

Gahh...pissed off again.

 

My org NEC 2SK68A jfets came, did a diode test and all read good values in the 800's, instead of replacing one in the 6 in the amp, I replaced all 6 of them as the original ones Stax used had silver letters bit different to the NEC ones I soldered in. Once done, measured the points again, the metal bridge voltage is now at 688vdc (50vdc higher than before), but all transistors have consistent voltages across all of them.

 

Plugged in my SR-5, there is a bit of channel imbalance, very slight with the left being stronger than the right, also there is a slight faint hum if volume turned down and some distortion if music is played with bass and low-end....any idea what is happening?

 

EDIT: Actually if I listen carefully, the right channel being slightly lower in volume is experiencing some distortion on bassy tracks and there is some hum on the right channel.

 

The left channel sounds fine.

 

Tested my SR-5 through my SRD-7SB MKII and all channel is fine.

Edited August 2, 2013 by DefQon

[Dusty Chalk]

Did you match the JFETs at all?  You may want to do that and run (as close to as possible) the same as possible.  6?  I understand 4 (stereo, +/-) and 8 (fully differential), but not 6 (fully differential on the hot, common ground?).

 

Someone who knows more about this shit please post, I know P. Diddy Squat about EE.

[DefQon]

Thanks for that, no I didn't match them. fuck.

 

6 in total, 3 per channel next to the offset/balance trimpots. 2 types of 4 main transistors per channel.

 

Spewing now.

 

EDIT: Spoke to soon, some hum on both channels, the seems to distort in the low-end spectrum of sound as the volume is turned up. Measured offset and balance all within 001vdc.

Edited August 2, 2013 by DefQon

[spritzer]

The were not used (then). They were stuck in customs at that time.

 

EDIT: I was referring to the recent 7/20/13 Cali meet. 

 

There were two other recent Cali meets. One near Los Angeles in Newport Beach and another near San Francisco.

None reported that the King Sound was present at those meets. They did make a showing recently at a New York meet.

So yeah, there is a used set out there.

 

It's the Cali Audio show this weekend or is it the next one...  not sure.  Anyway, aside from being such a douche there is the issue of heaps of people having paid in full not getting anything until the "distributor" orders more units.  Shouldn't people have been told so up front? 

 

I think the newest version of the coupe (xkr-s) is one of the sexiest cars

I have ever seen. But I would never own one again. Not even as

my 5th car. Tata motors, you gotta be kidding.

 

Don't tell my dad that as he really wants a new Range Rover.  At over 300K$ I told him I'd have him declared legally senile for such an act. 

[tkam]

Selling a demo model for full price is pretty shitty.  KG I hope you at least got in at the initial lower price.  The price increase that occurred was just a change in the MSRP - dealer costs stayed the same.  No idea how common that sort of thing is in the audio world but it seems kinda shady to me.  If they had announced that the initial price was a limited time thing that's fine but I don't believe that's the case here.

[kevin gilmore]

If I am willing to wait another 60 to 90 days I can get a new pair.

I have already been waiting since may. Not real happy with

The promised delivery dates.

[n3rdling]

Have the KingSounds here on loan right now.  Pin out appears to be the same as Stax pro bias.  Running from the normal bias jack of my SRM-T1. 

 

Spent some time at the dealer's place with the KS amps for about an hour.  The SS amp sounded better to me.  More control, blacker background, etc.  The tube amp sounded wimpier.  SS amp got really hot near the top...I think they're gonna have to look at more adequate heatsinking.  Both amps were RCA input only (SS had a loop out as well).  He popped the top off the tube amp to change the tubes, so I got a peak at that at least.  2x 12AX7, 4x EL84, and 1x dunno.  I'm pretty sure it was some kind of rectifier tube. 6-something-something-L I believe. 

 

Looks-wise, the headphones scream MADE IN CHINA.  The plastic is really cheap toy stuff and I wouldn't try to bend them much.  The positive to that is they're super light and quite comfortable on my head.  I don't know if somebody with a bigger head can wear these without snapping the headband though.  Pad material feels decent (better than ESP950), and they're rather large in diameter so my ears don't really touch anything.  Again, comfy.  Cups don't have much travel to move up and down, but can swivel from side to side freely so you can fold them flat if needed (think Grado pizza box).  Cups don't really seem to be able to tilt much...it looks like they should but I don't want to break them.  Cable and connector both pretty nice. 

 

You can't really see the stator design unless you hold it up to a pretty bright light.  Looks to be standard perforated metal, hole diameter about 60% size of those on the grill.  They're also using pinwheel/spoke bracing as found on the SR-Omega/SR-009.  Think 009 brace but with a quarter-size hole in the middle and 12 spokes.

 

I'll post impressions of the sound when I have some more time with them.

[jdkJake]

Low bar

The main problem with Heineken is that they pasteurize the crap out of the product for international shipment.

A brewery fresh glass is a whole different ball game.

Of course, everything seems to taste better in Amsterdam....

[DefQon]

Have the KingSounds here on loan right now.  Pin out appears to be the same as Stax pro bias.  Running from the normal bias jack of my SRM-T1. 

 

Spent some time at the dealer's place with the KS amps for about an hour.  The SS amp sounded better to me.  More control, blacker background, etc.  The tube amp sounded wimpier.  SS amp got really hot near the top...I think they're gonna have to look at more adequate heatsinking.  Both amps were RCA input only (SS had a loop out as well).  He popped the top off the tube amp to change the tubes, so I got a peak at that at least.  2x 12AX7, 4x EL84, and 1x dunno.  I'm pretty sure it was some kind of rectifier tube. 6-something-something-L I believe. 

 

Looks-wise, the headphones scream MADE IN CHINA.  The plastic is really cheap toy stuff and I wouldn't try to bend them much.  The positive to that is they're super light and quite comfortable on my head.  I don't know if somebody with a bigger head can wear these without snapping the headband though.  Pad material feels decent (better than ESP950), and they're rather large in diameter so my ears don't really touch anything.  Again, comfy.  Cups don't have much travel to move up and down, but can swivel from side to side freely so you can fold them flat if needed (think Grado pizza box).  Cups don't really seem to be able to tilt much...it looks like they should but I don't want to break them.  Cable and connector both pretty nice. 

 

You can't really see the stator design unless you hold it up to a pretty bright light.  Looks to be standard perforated metal, hole diameter about 60% size of those on the grill.  They're also using pinwheel/spoke bracing as found on the SR-Omega/SR-009.  Think 009 brace but with a quarter-size hole in the middle and 12 spokes.

 

I'll post impressions of the sound when I have some more time with them.

Thanks for the early impressions. But aren't these Made in China though? lol

 

I was hoping for a revisional update to the headband as you say, one look from pictures and it looks like it will snap in half. What's the diameter of the pads btw?

 

 

Anywho moving back to my SRM-1 troubleshooting. A few more new discoveries.

 

The jfets I ordered NEC 2Sk68A (low noise version of the regular 2Sk68 jfet, denoted by the "A" suffix) was not cut for the job. 

 

What I also learnt now after digging up datasheets and comparing the mA of the I(DSS) A values, there is a fucking horde of 2SK68A jfets. Why the fuck did the Jap's have to make everything so complicated with a single part number but various versions of the same semiconductor?

 

This also answered my previous ponderings. On the jfets it reads K68A K18X. The fucking K denotes it as different valued DSS(A) of the same class of 2Sk68A jfets. The amp uses 6 jfets in total. 3 per channel. All 2SK68A jfets. 4 of the Jfets are using K DSS versions and 2 are using N.

 

Here is what I discovered of the 2Sk68A N-channel jfet family:

 

2SK68A - N: I(DSS) Max. (A) is 12.0mA.

2SK68A - K: I(DSS) Max. (A) is 1.5mA.

2SK68A - M: I(DSS) Max. (A) is 6.0mA.

2SK68A - A: I(DSS) Max. (A) is 2.0mA.

 

And finally the NEC ones I ordered are L counterparts.

 

2SK68A - A: I(DSS) Max. (A) is 3.0mA.

 

I replaced all 6 of them with 3.0mA ones no wonder it fucking hummed and emitted some imbalance and distortion.

 

Now I know which jfet is faulty and it turns out to be the one I can't find a substitute online. 

 

Need a K68A-N jfet. Googling returns results from AK and diyaudio where users say the 2SK30A is a substitute for the regular 2Sk68A jfets except the N one I'm looking for which is rated for 12mA.

 

Anybody here might be able to point me in the right direction?

 

 

 

On other hand.

 

Golden 12S?

 

http://www.ebay.com.au/itm/ULTRA-RARE-Mint-STAX-SRA-12S-Golden-PRO-bias-NORM-bias-Modified-by-STAX-/200942962215?pt=UK_AudioTVElectronics_HomeAudioHiFi_Amplifiers&hash=item2ec9224627&_uhb=1

Edited August 3, 2013 by DefQon

[Sherwood]

 Why the fuck did the Jap's have to make everything so complicated 

 

The preferred nomenclature is "nips", so's ya knows.