[deadlylover]

Yeah the DIY T2 project is really something special. There's just something magical about continuing the Stax T2 legacy, as in today's economy, Stax just can't make them anymore for anything resembling a rational price. Hell, the original T2 was still "built to a budget".
 
And it really goes to show, Stax are completely badass. They know *exactly* how their headphones are supposed to be driven. And it wouldn't surprise me if they still have a couple of 'monsters' left in the factory to help voice their new headphones.

 

[dukja]

Quote:

heh, we should really post a page in DIY on the suitable parts for transistors, diodes, vol pot (bal/unbal), extra resistors for bal and where they go (and any other changes), caps (sizes and types, incl for styro replacement), some measurements of expected voltages (esp in the PSU section and bias). I was going to at some point, but still can't be bothered. Every 1-2 months someone ends up PMing me about the parts or measurements for SRM-1/mk2 repair or upgrades though and I keep copy pasting from old PMs

.

It's also sort of scattered across this thread, along with the old SRM-1/mk2 transformer rewiring that occasionally comes up.

 
Why don't you put all your writing (starting from the SRM-1 mk2 review) into a wiki here so that all the nice but scattered information from spritzer and Kevin can be kept.  I can help some with what I gathered from spritzer.  I even saw one person at the other site referring to your post trying to get some suggestion but just being treated poorly there.

  So those info will be greatly appreciated.
 
 

 

[svyr]

well, idk about wiki (the editor is probably very annoying for it), let's start with a thread....Should be easy, although not editable by everyone....

I'll start a thread in the DIY section and PM you a link/cross post one here. Would be a pity if all the info from spritzer and kevin went to waste when there are so many SRM-1/mk2s floating around waiting to be refurbished (you could pick up a half-dead one for $400 and then refurb it for another 100 or so, probably even balance it for the same amount (of course I'm not counting time spent)...(exc for the transistors, especially the hard to replace JR109 transistors )... There's also the info for rewiring the transformer that I think is somewhere in the thread.

Will probably take a couple of weeks to sift through my PMs for useful info/and or I wonder if there's a pic of voltage/resistance measurements (ballpark in-line, without the need to desolder) for the unit somewhere that I had before on an A3 pic of the schematics.

 

[Currawong]

Quote:

Also, I can actually hear that the 007tII is struggling with my Omega II's and I have the SR009's on order hoping that their extra sensitivity will mean that the 007tII is a perfect match.  Any one have any experience on this match and any views on whether my assumption is correct?  I mean, I know that there are other amps out there (e.g. Woo) but was hoping that the 009's are much better with the 007tII than the Omegas....

 
I'm pretty happy with a 007t as the amp for my 009s so far. I'll probably feel differently once I get a KGSS built, but I felt it was, to quote The Monkey, a bit too "polite" with the O2 MKIs.
 
Quote:

Yeah the DIY T2 project is really something special. There's just something magical about continuing the Stax T2 legacy, as in today's economy, Stax just can't make them anymore for anything resembling a rational price. Hell, the original T2 was still "built to a budget".
 
And it really goes to show, Stax are completely badass. They know *exactly* how their headphones are supposed to be driven. And it wouldn't surprise me if they still have a couple of 'monsters' left in the factory to help voice their new headphones.

Some of the DIY builds of the T2 are exceeding the cost of a Blue Hawaii SE I gather. It's pretty crazy.  Tempting though it is to get boards for the T2, I've decided to stick to the KGSSHV as my end-game goal.
 

 

[DaveBSC]

Quote:

Yeah the DIY T2 project is really something special. There's just something magical about continuing the Stax T2 legacy, as in today's economy, Stax just can't make them anymore for anything resembling a rational price. Hell, the original T2 was still "built to a budget".
 
And it really goes to show, Stax are completely badass. They know *exactly* how their headphones are supposed to be driven. And it wouldn't surprise me if they still have a couple of 'monsters' left in the factory to help voice their new headphones.

Indeed. The problem with electrostats is that you can't just grab a SOTA amp like an Apex Pinnacle and plug em in. Even beyond the DIY T2, I'm glad that companies like Headamp are providing support for truly SOTA electrostatic setups where Stax either can't or won't.
 

 

[livewire]

Quote:

 
I'm pretty happy with a 007t as the amp for my 009s so far. I'll probably feel differently once I get a KGSS built, but I felt it was, to quote The Monkey, a bit too "polite" with the O2 MKIs.
 

Some of the DIY builds of the T2 are exceeding the cost of a Blue Hawaii SE I gather. It's pretty crazy.  Tempting though it is to get boards for the T2, I've decided to stick to the KGSSHV as my end-game goal.
 

Get both board sets, that's what I'm doing.
Wont cost a lot to hold on to them and I am sure resale wouldnt be a problem in the future.(if you decided to off them)
Prolly too late for that now, the group buy is locked down.
Good luck with your KGSSHV build, I bet that you will still be longing for that T2 after it's done.

 
 

 

[J-Pak]

Quote:

I managed to get in the group-buy for the DIY T2 boards.  Just in the nick of time, so to speak.  Now I have to collect all the other stuff and also (apparently) build a rig to measure FETs for matching, as matched FETs seem to be needed in this thing. It's all pretty interesting. Lots of fun.
 
Someone is looking into having a batch of casework machined for the DIY T2s. This apparently is the second batch of  DIY T2s to be set loose upon an unsuspecting humanity.... 
 
Here's some of what I've learned so far:

1. There were 47 of the factory T2 amps sold by Stax 
2. 15 or so of the first batch of DIY T2s have either been built or are being built

 
It's a pretty exclusive amplifier, I'd say; even when this second batch of DIY T2s is built, there will be less than 100 T2s in existence, a number which includes all the factory Stax T2s and all the DIY T2s.
 
The DIY T2s are supposedly better, they have regulated power supplies galore, while the Stax T2 used fairly conventional transformer / diode / capacitor unregulated supplies mostly.
 
Someone ought to raise a statue to Kevin Gilmore, he's done heroic levels of design work on this stuff; and around that statue ought to be smaller monuments to all of the generous guys who organize and often FUND group buys etc.  My hat is off to them, too!
 
(An aside: I wonder  if we could ever convince Kingwah over at Audio-Gd to design / sell an electrostat amp????)
 
This electrostatic thing has really gotten me.  Maybe I can build a set of giant Sigma-like earcups and strap my Quad ESL-57's to my head.....
  
 
 

Well the other thing is the semis aren't your run of the mill $.50 pieces, some of them are $6 or $7 each. I think I am up to $250 in sand for just the amp section and that is with getting in on some attractive group buys that slashed the price of them in half

 

[milosz]

My SR-007 MK II's arrived today. I like them.
 
I like them more on my SRM 1  MK II than I do on my SRM-T1, I woulda thought just the opposite.
 
On the tube amp there's too much midbass, low bass is flabby too.  Upper mids and treble are nice.
 
On the SRM 1 there's a better mid / low frequency balance and bass is tighter, punchier.  Mids are good.  Highs are good, but not as good as they could be.  A little "scratchy."  Kinda.
 
It'll be a year before I finish the DIY T2 but I am looking forward to having a better amplifier, although the old Stax jobs are pretty decent really. Not "reference" but pretty darn good.
 
One thing I noticed with the SR-007's.  When I adjust the headset on my head, move the earcups around, there's that usual Stax "crackle."  (Which is scary, what is going on?)  It seems like the air pressure changes from moving the earcups around on my head are pushing the diaphragms into the stators, is that really arcing I hear?  Or is it just the dust covers crinkling?  The right earcup does this a lot more readily than the left, a better seal on that side I'd guess.
 
I notice this with my Lambdas too.  I hope it's not destroying my Staxes.

 

[deadlylover]

Don't worry, the sound is normal (and quite scary sounding on the O2's eh?), that's just how they roll. We call it the Stax fart.
 
Have fun playing with the fit, it took me quite a long time to get them to fit and sound the way I wanted.

 

[Leonardo Drummond]

Quote:

Don't worry, the sound is normal [...]

...and VERY annoying.

 

[svyr]

...and VERY annoying.

lol, i even posted it as a 'major drawback' of electrostatics in one of the threads asking what sort of problems you might have with them or what their weaknesses are.
A few pages back someone suggested putting a small straw or tube under part of a pad to relieve the pressure, that was for /\, but you can try it for 007 as well.

 

[DaveBSC]

Quote:

I like them more on my SRM 1  MK II than I do on my SRM-T1, I woulda thought just the opposite.
 
On the tube amp there's too much midbass, low bass is flabby too.  Upper mids and treble are nice.
 
On the SRM 1 there's a better mid / low frequency balance and bass is tighter, punchier.  Mids are good.  Highs are good, but not as good as they could be.  A little "scratchy."  Kinda.

 
It's partly a voltage swing issue. The 007 demands voltage, and the SRM-1 Mk2 has more of it than the T1 does. None of the in or out of production Stax tube amps have near enough voltage swing. (T2 excepted of course). The T1 was 300V, the 007Tii has 340V. To get the Omega 2 really moving, you need 400V+.
 
 

 

[deadlylover]

Quote:

It's partly a voltage swing issue. The 007 demands voltage, and the SRM-1 Mk2 has more of it than the T1 does. None of the in or out of production Stax tube amps have near enough voltage swing. (T2 excepted of course). The T1 was 300V, the 007Tii has 340V. To get the Omega 2 really moving, you need 400V+.

 
It's safe to assume its pretty much an issue of MOAR POWER. I think the O2 tends to love having some standing current on the output devices to munch on.
 
Quote:

...and VERY annoying.

 
Yeah it's pretty annoying when you're trying to enjoy a spot of breakfast while listening/watching something and PSHHWT PSHHWT.
I just intentionally wear the O2's wrong to break the seal in that case

 

[MrGreen]

That sound is famously known as the "stax fart". It has to do with the lightness of the diaphram, and the currents (change in air pressure), caused when you push the cups on your ears, or sometimes move them. You're essentially moving the diaphragm, and they're accentuating the sound of the air.

 This same principle has been adopted by Stax in their line since the Lambda Signature, I believe, which was the first to remove mechanical damping, and just use the air pressure around us to stop the diaphragm once flux has stopped (since the "plate" is a low mass and wide surface area, the wind resistance stops it very quickly, although not as quick as many dynamic systems).
 
BoPET (the material the diaphragm is made from) has a relatively high tensile strength, so you won't be damaging it. It's certainly less stressful than playing music through them.

 

[Amarphael]

It's a bit puzzeling me that i have no issue whatsoever with the fart when i'm with the O2 on, even though i  don't eat while wearing them i do occasionally yawn (late night listening) and grooving with the music and no unwanted sounds bother me at all. Only when i adjust the earcups that i get the PSHHWT PSHHWT lol... Does this mean i don't have a proper seal? But they sound so goooooood.