The Headcase Stax thread

[Earspeakers]

I predict beautiful, beautiful music.

 

I'm already getting that! I have yet to meet the Stax I didn't like. 

 

Though the 4070 came dangerously close until I got to understand it. Next test is the Siggy coming in after repair. 

[spritzer]

All the SR-303/404 drivers had the red rings, no matter what headphones they were used in.  4070, SR-SC1 and 404LE

 

As for the 007Mk2.9, they still sound awesome and easily trump the 009 with just the ports plugged.  I just prefer the meatier sound of the 007's as the 009 can be a bit thin at times, even the new ones.  The 007mk2.9 isn't quite as smooth as the Mk1 but it just gets out of the way better than the 009.  Equal or even better detail retrieval than the 009 and the bass is the best anywhere, it's just perfect - tight yet tuneful. The 009 can't compete here as it's bass is... well how to be diplomatic here... lacking.  Yeah... let's go with lacking. 

 

I've been spending a lot of time on the KGST lately and here the 007Mk2.9 just fits perfectly.  Really shows off what circuit can do and why it's such a favorite of mine. 

Edited March 27, 2015 by spritzer

[Dusty Chalk]

I'm already getting that! I have yet to meet the Stax I didn't like. 

 

Though the 4070 came dangerously close until I got to understand it. 

And they say burn-in isn't real!

[Earspeakers]

And they say burn-in isn't real!

 

Ha, it is! The real name is "psychological adjustment". At least when it comes to Stax - dynamic drivers do actually loosen up. 

 

All the SR-303/404 drivers had the red rings, no matter what headphones they were used in.  4070, SR-SC1 and 404LE

 

Ah, thanks. See below

 

 

 I just prefer the meatier sound of the 007's as the 009 can be a bit thin at times, even the new ones.  

 

Bingo. Staxen sound more alike than different, but I'm hearing two axis which do change.

 

One is detail - the lesser Stax don't seem to exactly lose detail, but it gets "fuzzed". Most obvious in the bass region in my experience - the contextual detail of the sound (i.e. a cello string) seems to be there, but it's fuzzed out compared to a better Stax. So there seems to be a sliding scale, the 207 being low on that, and the 009 and 4070 being high. 

 

Two is weight, presence or "meat" as you say. The 4070 has this the least in my experience so far, and yes the 009 has this quality (thin/delicate/airy), as does the 404LE. The new Lambda line has quite a bit of oompah. The Nova is a little unique, a bit on it's own as not too fuzzy, not too meaty, but warm and in the middle there. Now with the oomph the downside is that you lose the delicacy and some of the "air" of the other ones, which have a more refined sound. 

 

Anyhow that's what I'm hearing so far - love them all and listen all day while I work. I'll switch headphones for variety. And in terms of personal balance between these two axis which do I like best? I'd have to say the 404. Seems to get enough of everything just right, but I still don't want to listen to just one for 12 hours. 

Edited March 27, 2015 by Earspeakers

[gepardcv]

As for the 007Mk2.9, they still sound awesome and easily trump the 009 with just the ports plugged...

 

I've been spending a lot of time on the KGST lately and here the 007Mk2.9 just fits perfectly.  Really shows off what circuit can do and why it's such a favorite of mine. 

 

Damn it. I was planning to wait to get the 007Mk2.9 after I finally finish building the KGST. Now you're tempting me into placing a PJ order sooner rather than later.

[Dave R]

On PriceJapan where I got my 009's and 003mk2's, they've got the SR-007A ( SR-007mkII ), so excuse my ignorance but what is this 007mk2.9 ?

[Earspeakers]

Damn it. I was planning to wait to get the 007Mk2.9 after I finally finish building the KGST. Now you're tempting me into placing a PJ order sooner rather than later.

 

I wouldn't hyperventilate if I was you. Spritz likes one kind of tone and found a pair that does that, you might like another. With Stax I'm not seeing that theres a holy grail of headphones. They're all much more alike than they're different, and the differences are subtle and basically come down to dialing in delicacy-punch and detail-warmth. Others may disagree, but that's what I'm hearing so far from some 10 different models in hand (pretty much the complete Lambda line). I'll have the latest 007 to compare to a mk 1 (carbon box) next week. 

 

 

On PriceJapan where I got my 009's and 003mk2's, they've got the SR-007A ( SR-007mkII ), so excuse my ignorance but what is this 007mk2.9 ?

 

Just a name people are using. 

[Dave R]

OK, thanks.

[Earspeakers]

Speaking of which, I question the idea that Stax is extensively changing or even tweaking these production lines. I work in a similar business. While we're not as small as Stax by far, my product is the best scientific instrumentation in the world for this particular application. The devices are expensive ($100k), small (handheld), and specialized. I've also worked in similar industries so have experience in these kinds of production lines. 

 

FIrst, it would be very unusual for a company to change an existing line while in production, for several reasons. 

• Motivation: there is none. Extensive R&D has gone into the existing design, who in their right mind would want to mess with it while trying to get product out to customers and make bills? Another way to say it, "don't mess with your cash cow"
• Difficulty: it's called "changing the airplane engines while in flight".  Any change has potential side effects that only show up over time, who would do this on an existing production line?
• Staffing. R&D is always tasked for the next products, why revisit what is working and selling, and who has staff for that? 
• Cost. Small production lines are expensive. Suppliers only want to do one, simple thing. Changing and making variations costs money and time. Certainly some things like coatings are not changed, except for necessity or good reason. Additionally it would be unlikely there would be great variation across the products for the basic components like film and coatings, it's too expensive (another topic would be production line design, which is how to create a myriad of seemingly different products that are actually just small variants of each other)
• Change sells. In other words, say you figure out an improvement, why would you give it away for free and unannounced on the existing line? You'd be crazy to do this, what you'd want to do is create a new product and trumpet the improvement. 

I've never seen it at any company that anything changes in production except for bug fixes, and reluctantly at that. Now note I'm not arguing whether people are hearing some kind of variation with the existing production line, but it's highly unlikely they've actually changed the line. If it is true, then it's highly likely to be sample variation. 

 

And if that was true, I'd say either Stax has poor control over production (seems unlikely), or that the headphones are so difficult to manufacture that there is an inherent degree of variability (this happens frequently, such as with silicon). And if that was true, the variability wouldn't be systematic, but instance based. Meaning a batch of headphones from one day would all be different. Systematic variation would have to be due to something like what the humidity was when they made the headphone (just an example, Stax appears to assemble in a 'near cleanroom' environment). 

 

Edit: I'll add that I happened to work in Japan for years in this industry, so have a sense of how the Japanese electronics industry works. Production engineering is mostly the same world wide, but for a Japanese only company like Stax I'd opine that it would be extremely unlikely for them to do this. Japanese companies are very conservative in this way, only the Germans are their equal. 

Edited March 28, 2015 by Earspeakers

[skullguise]

And yet, it's thought that Japanese and German (Stax, Sennheiser) have done just that.

Audiophile manufacturers might not be as easy to classify as other manufacturers. Tweaking for better sound ( or marketing a new revision) is common....

[spritzer]

All products go through constant evolution so why would Stax be any different?  Those of us who have opened up a lot of the stuff Stax have built over the years know just how frequently things are changed with zero notification of that change.  There are at least 4 very different versions of the SR-007Mk1 but they never changed the name.  The SR-Omega came in three versions and that was with Stax on their last legs.  The T2 came in at least two versions and the SRM-T1 versions are probably about a dozen or so with the W and S variants.  The SRM-1 Mk2 takes the cake though, it was in constant design mode with part changes, design revisions and new circuit boards.  Ditto for the small Stax amps, three very different versions of the SRM-Xh exist out there, they aren't even closely related. 

 

It has also been confirmed why Stax altered the headphones. 

[Earspeakers]

All products go through constant evolution so why would Stax be any different?  

 

Agree, but that's not what I'm saying, which is that it is unusual for a company to make changes (beyond bug fixes and small tweaks) in an existing product line. Of course they are evolving. 

 

Those of us who have opened up a lot of the stuff Stax have built over the years know just how frequently things are changed with zero notification of that change.  There are at least 4 very different versions of the SR-007Mk1 but they never changed the name.  The SR-Omega came in three versions and that was with Stax on their last legs.  The T2 came in at least two versions and the SRM-T1 versions are probably about a dozen or so with the W and S variants.  The SRM-1 Mk2 takes the cake though, it was in constant design mode with part changes, design revisions and new circuit boards.  Ditto for the small Stax amps, three very different versions of the SRM-Xh exist out there, they aren't even closely related. 

 

 

Now we're talking about amps, maybe I wasn't clear but I was discussing headphones above. When circuits are involved as you well known parts and suppliers are much more volatile. In this case more variation is certainly possible for a small manufacturer who can't secure production agreements. This doesn't contradict my point though, as these are changes forces onto OEM's by suppliers. And yes with change oftentimes tweaks will slip in there too. 

 

It has also been confirmed why Stax altered the headphones. 

 

 

Which is? Usually it's for reliability, manufacturability or cost reasons. 

[spritzer]

The point is that it isn't unusual.  For the amps I did not account for part changes due to supply or obsolescence just fundamental changes to how they were built. 

 

Your argument is made even worse as it doesn't account for the general mentality at Stax.  Constant changes are the norm and there is no looking back, new is always an improvement.  It's been like that from the 60's. 

[DefQon]

Some internal driver pics.

 

Numark ES-701 (same driver used in the Kmart, Pioneer and Lafayette clones)

 

Odd driver construction. Mine came in original box and manual and looks relatively unused, but takes a while to charge up and distortion instantly kicks in with sub-bass music.

 

 

 

Also received a half arsed Stax SR-60 electret (marketed as SR-30 in non Europe regions, so USA, Oceania etc). Got my partial refund from seller months ago, there was almost 0% sound, leaving it to charge a few days didn't work, unit looked to be tampered with. Always wanted to disassemble one of these electret drivers as they are absolutely destroyed when pulled apart:

 

 

 

The driver itself taped up ... well not for long...

 

 

Dust protector (backside)

 

 

Tape removed:

 

 

And this is why there is almost no sound output regardless of power and volume, looks to have been stored away in piss poor conditions stretching the electret film. I tried to do a quick repair ML style by reheating the membrane but it was no go, the film seems be stretched as per spec by a special machine jig when Audio Technica made these electrets for Stax.

 

 

They are currently in the process of being turned into full blown ESL headphones. The spacer and bias connection is proving to be a problem at the moment as the yellow tape was the thing holding the driver together.

 

Anyway here's one for Spritzer, not sure what circuit design I got outbid on the last second:

 

http://buyee.jp/item/yahoo/auction/k182173704

 

I purchased the other Stax tube amp from the same seller he was selling a month before.

 

http://buyee.jp/item/yahoo/auction/d163346459

 

This is the amp I was asking about converting the bias from the claimed 470vdc to full or near 580v pro-bias in the KGST normal bias thread in the diy section.

 

There is a switch to change from normal to pro-bias, but as mentioned some compression and distortion if volume pushed too high with pro-bias headphones. It sounds pretty sweet though. There are 2 260vac taps and 1 350vac tap on the secondary winding of the trafo. 

 

Here are some internal pics of the circuit (bit messy but the amp is smaller then the SRA-3S and about same size as my SRD-7 SB MK2's:

 

 

Edited March 29, 2015 by DefQon

[spritzer]

With those AC levels it is easy to get pro bias.  The 350VAC tap pushed right up against the 1000V rating for most of the parts so you'd need 1200V caps and diodes and then a voltage divider to bring it back down to 600VDC.  The B+ in that amp might be in the 600V range for the the last tubes.  What is the voltage on the tie points for those 27K resistors? 

[Earspeakers]

The point is that it isn't unusual.  For the amps I did not account for part changes due to supply or obsolescence just fundamental changes to how they were built. 

 

Your argument is made even worse as it doesn't account for the general mentality at Stax.  Constant changes are the norm and there is no looking back, new is always an improvement.  It's been like that from the 60's. 

 

OK, they must be unusual. Small manufacturer. 

[kugino]

so i'm thinking about picking up a used 717 for a sr007A coming in...i don't have the funds for a kgsshv yet. but i just saw a modified exstata on spritzer's site. would this be on par with the 717 driving the sr007A or would i be better off with the 717? they'll be within $100 of each other cost-wise...

[JimL]

I'm sure spritzer will be along to comment on sonic merits of the two amps but if it were me, I'd go for the 717.  From what I've read the 717 has a similar circuit design to the KGSS, with the major difference being a much simpler power supply.  However, sound quality aside, the HUGE advantage the 717 has is that if and when you get a KGSSHV and want to sell your old amp, you should be able to get a good price for a 717 on eBay as it is a commercial amp and a known quantity.  Everybody who has even a passing acquaintance with electrostatic headphones has heard of Stax.  The exstata is going to be much tougher to sell as it is a DIY amp and few people outside of Head-Case or Head-Fi have ever heard of it.  Anybody can go on ebay, look at closed auctions and get an idea of what a Stax amp sells for.  Where do you go to research that info for an exstata?

Edited April 1, 2015 by JimL

[eggil]

Chip Quik has worked great for me w hen desoldering heat sinks. It may work for Teflon tube sockets too.

[spritzer]

The 717 is a modified KGSS so far superior to the Exstata.  The latter was always a bit of a bastard and with roughly 1% THD the sound isn't for everyone.  I tried to fix it the best I could on those boards but it's still a very warm and thick sounding amp.  Some people like that sound and it will work well with the older 009's but it isn't the last word in fidelity. 

[insanity]

I have a strange problem occuring with my few days old new SR007. One driver makes strange noises that are not very loud, but noticeable, especially when no music is playing. It comes and goes and it can be provoked by pushing head cup towards the ears while wearing the headphones. Its like a high pitched sound that slowly reduces in frequency. I am yet unsure if there is a real channel imbalance that comes and goes, or if I am justing imagining a volume imbalance. I will continue comparing with the SR009 which I have never had problems with. The problem has occured on both the KGST and KGSSHV. With the SR009 I hear dead silence so its neither the amps nor the source.

 

Has anyone ever experience a similar thing with a 007?

 

Furthermore I am really surprised how much more "juice" the 007 needs compared to the 009 to reach the same volume. 

[spritzer]

Has to be debris inside the driver so they are defective.  I'd just return them and get a new set. 

[ktm]

I just bought a sr-80 and srd-6 to use with my second system. It sounded pretty good, no balance issues.

But some bass stuff was not up to par.. I thought it was just the nature of the sr-80's.

On a whim I hooked it up through a srd-4 I had sitting around. There's the missing bass. The cutoff point was lower.

The overall sound was warmer as well. Are the two boxes that much different, or is there an issue I need to check for?

[spritzer]

So many design variations of the SRD boxes to know what they did in any one of them but the SRD-6 could have been overloaded at some point and thus some parts were damaged.  Stax never built any EQ into these. 

[ktm]

I'll have to pop the top on the srd-6

I'm sure there's not too much in there to go bad.

The sr-80 is a bit lighter in bass than the sr-40.

But the lack of side to side movement on the wire arc of the sr-40

makes it hard for me to wear. The sr-80 fits much better.

At some point I'm going to have to build a new amp for the sr-202's.