[DaveBSC]

 
Quote:

Now the best part, you can build one of these for under 500$. 

  All parts are easy to get and the project will be accompanied with a full BOM plus detailed instructions on how to build one.  The power transformer have to be custom ordered but companies like SumR provide such excellent service that this is by no means harder then picking up a prebuilt unit.  You are also only paying for stuff you need and the transformer can be optimized for audio use. 
 
I hope you are as excited as I am...
 

A super KGSS that's better than the Headamp version for less than $2300 would be great. But... I don't really have any interest in building it myself. Would anyone be willing to provide the service of building these?

 

[edstrelow]

Quote:

 
The 003 is pretty close in presentation to the Omega 2 (mk1) whereas the 303 and 404 are quite different. The 003 is warm and fairly forward in the midrange, has good bass that could go a bit deeper and highs that aren't emphasized and lack a little bit of extension. The speed is pretty ridiculous though and midrange tone is about as good as it gets at this price, or just about anywhere for that matter. They also offer a small but focused soundstage with good imaging, and sound very fluid. The Omega 2 is of course better in just about all respects and is much better at the frequency extremes, but tonality is similar and the overall warm, fluid, and very focused feel is pretty close, so if you like the 003 the O2 is the natural way to go.
 
The 303/404 has a much bigger soundstage but its imaging is more diffuse; it sounds like it's trying too hard to be spatious and loses some imaging accuracy as a result. Its mids are tilted up towards the upper midrange and lower mids are a bit lacking, which gives it a somewhat unnatural and honky tone; that's the main flaw that turns me off from these headphones. They're drier and less fluid than the 003, but they aren't dry in the absolute sense and can still be quite fluid if the source and amp are up to spec. The bass is pretty good and goes very deep, the highs are very extended if a little bit hard in the lower treble, resolution is excellent and in general these are really great headphones for ambient music - the huge soundstage really makes things sound very airy. Properly driven they can sound like Grados with soundstage, forward and punchy, but from most Stax amps they'll be a lot more laid-back.
 
I prefer the 003 over the 404 by a good margin. The 404 would be a better headphone if not for the mids, but I just can't stand that coloration. The 303 is the same as the 404 minus a bit of transparency. Go for the 005 system, but expect to spend a not inconsiderable amount of time trying to get the damn headphones to fit properly - they're like an IEM in that they need a good fit or they can sound congested - and even at the best of times they're not that comfortable. But there's very little that competes with them in terms of sound quality for the buck and they will beat out many full-size systems that they should have no right to even come close to. The headphones also scale really well and can sound scary good out of a higher-quality rig.
 
I'm not a fan of the K701, the HD650 will scale really well and can sound downright fantastic in the right rig, but then again so can the 003. I think in most rigs the 003 will sound better. They're fairly similar actually in terms of overall feel, though the 003 is of course much faster and more forward.

I can't agree with this assessment of the 404 vs 003.  I have both, in fact two 003's and the portable version the 001Mk2 with its own amp, and while I think they are great phones and a very good bargain way to get into Stax, they lack both deep bass and treble.  As well, the sound field is constricted compared to the 404, probably due to the fact that it is an in-ear design and bypasses the external ear.  The 404 is by comparison a full-range phone which is still better, in my estimation than the other Lambdas I have had. Still the 03 is a very good starter phone with no harshness.
 
http://www.head-fi.org/forum/thread/430113/stax-lambdas-404-vs-signature-vs-nova-classic
 
The 404's and some other Lambdas get some flack because of an edgy mid-range and treble.  This is somewhat source dependent, i.e. it may not be  an issuse with the right DAC or cables. Also the phones need to be properly warmed up and  I suspect sensitive to the "electret effect" aka "parasitic charge" effect in which the drivers may build up a voltage bias.  This is a general problem with electrostatics and is a better-known issue with electrets.  Things like discharging the pins when you take the phones out help.  I try to leave my phones plugged into the amps at all times even if the amp is off.
 
However I have come to realize that the harshness is also caused by Stax' use of a thin foam backing beind the drivers.  I have removed this from my both my 404 and Lambda Signature and feel this has eliminated most such harshness as well as expanding the sound stage.
 
 
http://www.head-fi.org/forum/thread/443060/is-the-stax-lambda-signature-supposed-to-be-damped-on-second-thought-ditch-the-foam-backing-on-all-the-lambdas
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I had my first experience with Stax yesterday, and I fell in love with the 007MKII (powered by the 717). I was comparing it to my D7000 and I prefer the O2 in every way--it's just far more natural and textured, and while the 30Hz region is a bit rolled-off compared to the D7000, it surprising matches the lush and full-bodied deep/punchy bass of the D7000. Other headphones I've tested where the 30Hz region is rolled-off cannot pull that off (such as the W1000X, DX1000, HD800...etc).
 
So now I'm planning on my very first Stax purchase (also my first electrostatic), and I've seen different opinions. Some say the MK1 has deeper bass extension (but less mid-bass and mids) than the MK2, I don't know if the MK1's deeper extension and leaner mid-bass will be able to match the D7000's lush and full bass as well as the MK2.
 
Also, I originally wanted to test the 4070, since I read that being closed-back, it should have better bass extension, but it seems some people are saying the opposite--that the O2MK2 actually has deeper bass than the 4070, despite being open-back?
 
As for the amp, someone PM'd me and said that he and his friend has compared the more expensive Stax amps to the cheaper Stax amps, and the cheaper ones sounded the same as the expensive ones, so I shouldn't bother paying more for the more expensive amps. He didn't want to post this publicly as he felt people will jump on him for saying so. Is he right?
 
In general I don't like to deal with tubes for anything--the hassle of replacement and warming up is just not worth it to me. I much more prefer solid state.

 
I have tried my 007A on my lesser Stax amps and can say you are are losing a lot of sound quality compared to, say, the Stax 717.  The sound was rather muffled with my SRM-3,  somewhat better with my SRM1Mk2 but still not on a par with the 717.  The issue seems to be the amount of volts these amps can apply to the electrostatic drivers.  Th SM3 does 300 volts, the SRM1Mk2 does 340 I believe, while the 717 does 450.  Some of the very expensive super amps for Stax go even higher. 
 
You will hear some of the quality of the 007A with the lesser amps but I would say save my pennies for a 717.
 
As regards the 007 Mk1 vs the 007a (aka Mk2)  I was very cautious about buying the newer A model when it came out, because of a number of negative comments versus the 007Mk1. On the other hand there has been some criticism of the Mk1 as sounding dark because of its somewhat rolled off treble.( See the discussion above of the similarity betwen the 003 and 007Mk1).   Finally I  was prepared to go for the newer model after Spritzer came up with some minor mods.  In particular I recommend flatening the spring in the ear cups.
 
http://www.head-fi.org/forum/thread/381975/to-tweak-or-not-to-tweak-the-stax-007a-that-is-the-question
 
 
When I finally had a chance to directlly compare my tweaked 007A vs the original 007Mk1 I found little to chose between them.  The 007A has more uper midrange and treble.  Bass was similar, but the 007A had somewhat of a peak towards the bottom.  The criticisms of the 007A seem to have largely abated and the 007 seems to be pretty widely accepted as a worthy sucessor.   
 
I would say get a Mk1 if it is in cood condition and significantly cheaper than an 007A.

 

 

[BoilermakerFan]

So you have a problem with a commercial version of an eXStatA, but no problem with a commercial version of the Birgir/KG DIY design?      Interesting...
 
Quote:

 

This is DIY only for now but I see no problem with commercial version being built in the future unlike using the Exstata design as the basis of a commercial venture.  Whether Headamp will build it is up to Justin.
 

 

[HeadphoneAddict]

Quote:

So you have a problem with a commercial version of an eXStatA, but no problem with a commercial version of the Birgir/KG DIY design?      Interesting...
 

If the eXStatA were to remain as a DIY design in addition to commercial, I suspect his objections would disappear.

 

[El_Doug]

Hooray!  Now you can move onto the kilovolt SS

  I'd still be more than happy to front some money for experimentation
 
the KGSSHV sounds absolutely fantastic!  hopefully this will bring even more people into the 'stat fold  
 
Quote:

I wanted to let all the Stax fans know that there are some very important news on the amp front for us.  Dr. Gilmore and I are working on a new version of the KGSS (here after called KGSSHV) which will be a DIY based attempt to give people a truly high end electrostatic experience on a budget.  There will be a thread on this subject soon in the DIY forum but I wanted to give you lot the first heads up about the new project. 

  At it's core it is basically the same circuit as the much loved KGSS but with a few very important improvements, higher rail voltages then the stock amp (+/-500V compared to +/-350V), a constant current source loaded outputstage (which the KGSS lacked) and the best part, it is fitted with a truly top of the line PSU, the same one as can be found in our DIYT2 project.  With these improvements we have an amp which can give any of the tube based units a run for their money (T2, BH, WES and ESX) with the comfort and lack of fuss SS brings to the table. 
 
The boards are designed to be fitted to large, side mounted heatsinks.  The amp board has both channels on one PCB and the PSU is alos complete on one PCB.  They can either be mounted on either side of a single chassis or in two separate boxes.  The amp board is fitted with a spot for the volume pot and PCB mounted XLR jacks but there are also porvisions for normal input tabs.  The volume pots the boards are designed for are all 4-gang, a DACT CT-2, TKD 4CP-601 and a custom made Alpha pot which I had made for me.  These are cheaper then an RK27, sound better and I'll be selling them from my own stash at cost. 
 
Now the best part, you can build one of these for under 500$. 

  All parts are easy to get and the project will be accompanied with a full BOM plus detailed instructions on how to build one.  The power transformer have to be custom ordered but companies like SumR provide such excellent service that this is by no means harder then picking up a prebuilt unit.  You are also only paying for stuff you need and the transformer can be optimized for audio use. 
 
I hope you are as excited as I am...
 

 

[kevin gilmore]

I absolutely know how to do a version that runs at +/-1000 volts. 
In fact i have a working prototype with 2100 volt parts.
Would work great for ESL63's.
 
Anything over +/-580   (the diaphram bias voltage) will likely damage
the headphones as the diaphram will become negative with respect to
the stators. Then bad things happen. Same thing if your turn up the
volume too much on any of these amps when you have the low bias
headphones plugged in.
 

 

[spritzer]

Quote:

Anything over +/-580   (the diaphram bias voltage) will likely damage
the headphones as the diaphram will become negative with respect to
the stators. Then bad things happen. Same thing if your turn up the
volume too much on any of these amps when you have the low bias
headphones plugged in.

There is an easy solution to that, either we move onto Jecklin Floats (+1200V bias) or we design our own headphone with a 0.7-0.8mm D/S gap. 

 
Woot, I've got a new custom title...

 

[AppleheadMay]

Quote:

 
Woot, I've got a new custom title...

Congrats!  

 

[Lunatique]

Quote:

The criticisms of the 007A seem to have largely abated and the 007 seems to be pretty widely accepted as a worthy sucessor.  
 

That's good to know. The one I listened to was the 007MKII, and I loved it.
 
As for the amp, since the 717 is discontinued, is the 727 a bad idea? I keep seeing people saying how the 717 is "far" better than the 727, but is there proof of that? The 727 doesn't seem to be available in some Asian countries anyway--most are still selling the 717 it seems. Why is that?
 
I know people will try to recommend the Blue Hawaii or Woo amps, but I am just not ready to spend that kind of crazy money on an amp yet. This new venture into Stax headphones is already very damaging to my finances, and I'm entering it by getting the flagship model right off the bat (mostly because it's the only one I've listened to).

 

[El_Doug]

when do yall expect the KGSSHV pcb's will be ready?  I don't want to miss out on this! 

 

[perrew]

Im sure there will be a LOT of buyers for the chassis group buy, Im very interested at least!
 
Quote:

 

Some parts might be a good candidates for a group buy, for instance a chassis with side mounted heatsinks, transformers and having the angle brackets (which transfer the heat from the transistors to the heatsinks) machined.  Teflon Stax sockets would also be another candidate. 
 

 
 

 

[AppleheadMay]

How does a group buy like that work? With buyers from Europe and the US for example?
We place a group order, all pay separately and they ship to everyone individually?
I'd be in for whatever group buy that has to do with this amp. 

 

[Currawong]

Quote:

when do yall expect the KGSSHV pcb's will be ready?  I don't want to miss out on this! 

From what I gather, it should be reasonably soon, as it uses the existing KGSS board + a less complex version of Kevin Gilmore's T2 power supply. 

 

[El_Doug]

I was under the impression that it used a new amp pcb, and not the existing kgss board, though it would be possible to use the kgss board provided the new output stage was constructed separately
 
Quote:

From what I gather, it should be reasonably soon, as it uses the existing KGSS board + a less complex version of Kevin Gilmore's T2 power supply. 

 

[kevin gilmore]

new amp board
http://gilmore.chem.northwestern.edu/kgsshvamp.jpg
 
new power supply board
http://gilmore.chem.northwestern.edu/kgsshvps.jpg
 
amplifier schematic
http://gilmore.chem.northwestern.edu/kgsshv.pdf
 
power supply schematic
http://gilmore.chem.northwestern.edu/kgsshvpower.pdf
 
forgot the bom which needs lots of work
http://gilmore.chem.northwestern.edu/kgsshvbom.xlsx