[spritzer]

As with so much of the stuff we do, Kevin and I don't spend a lot of time discussing it in public.  Boards for the improved version were ordered and the improvements are nothing short of drastic, bringing the sound much closer in quality to the KGSSHV.  Here is a (rather large) picture of the populated boards:
 
http://img833.imageshack.us/img833/4126/exstatav2.jpg
 
As it happens they are sitting on my desk now since I finally got a chassis for them and the PSU.  I will use most of the same parts as in my other Exstata so I can easily compare the two.  This build used 2SA4686A's and 2SA1831's for the CCS (I ran out of 2SA1968's). 
 
Granted the boards are larger than what Alex drew up but that's just because I had the KGSSHV layout and modified it to fit plus I decreased the board size a bit.  In reality this version is just a little bit more expensive to build while being much superior in every way.  Far higher voltage swing with +/-400V rails, more standing power for the output stage and distortion a few orders of magnitude lower.  We won't make any more of these boards though since we have a new "poor mans" ready for testing.  Same power supply as the KGSSHV but all tube, balanced from input through to output. 

 

[Sathimas]

 
Quote:

We won't make any more of these boards though since we have a new "poor mans" ready for testing.

 
Sounds interesting
 
Not that I have time or money for another electrostatic amp at the moment (building an EHHA)
but nonetheless I'd like to stay informed - is there any website where I can find more information?
 
By the way - those distortion measurements - were they done with the hybrid or the SS version?
I know next to nothing about the circuits or whatever devides a good one from a bad one - so please
excuse my naive questions.
 
 
Quote:

So why jazz up the Exstata when you can just start with a more robust base design?

 
It sounded like with small improvements (e.g. changing few parts) a much better performance could be achieved.
(And I don't have that much money to spend on audio gear, at least not at the present time.)
 
If that's not the case, I'll just live him as he is and enjoy the sound since it (with Lambda Pro) still sounds better to me than
for example a HD800 / Lehmann BCL  or AMB M³ combo did.

 

[spritzer]

Quote:

 
By the way - those distortion measurements - were they done with the hybrid or the SS version?
I know next to nothing about the circuits or whatever devides a good one from a bad one - so please
excuse my naive questions.

Both versions were tested, the tube version tested slightly better but we focused on improving the SS version as I never saw the point with the hybrid.  Same improvements can be done to that as well.

 

[Keithpgdrb]

I have the exstata hybrid boards here, unbuilt.  is there a link to where the improvements are documented.. meaning what parts are changed out, and the improvements?  Or would it be better to wait to build the new poor mans amp, whatever that is.  I dont think I want to build more than one amp for my stats, so I have to make it count.

 

[spritzer]

Sorry about that, not enough sleep for months now... 

 
You could never fit the updates to the circuit on those PCB's unless you get very creative with the chassis you put it in (i.e. for extra heat handling).  It also needs a new PSU for the higher rail voltages. 
 
I would build them all but then again I'm a compulsive amp hoarder. 

 

[Keithpgdrb]

Sorry about that, not enough sleep for months now... 

 
You could never fit the updates to the circuit on those PCB's unless you get very creative with the chassis you put it in (i.e. for extra heat handling).  It also needs a new PSU for the higher rail voltages. 
 
I would build them all but then again I'm a compulsive amp hoarder. 

Hmm. I was getting ready to start this project. Maybe I will put it on hold till more information comes up on the poor mans amp. I generally only watch head fi. And there isn't much on any exstata problems. I had no idea improvements were being made. I'll do some more research before I proceed with anything.

 

[marcus1]

With the new "poor man's amp", any idea what the distortion measurements are as yet - better than the exstata?
 
thanks
 
Quote:

Both versions were tested, the tube version tested slightly better but we focused on improving the SS version as I never saw the point with the hybrid.  Same improvements can be done to that as well.

 

 

[AmarokCZ]

He wrote "...and distortion a few orders of magnitude lower." so the distortion will be surely lower. Even my electrostatic design (see signature) has lower distortion (0.05% @ 450Vrms/1kHz) which is quite something considering its simplicity.

 

[Forte]

Quote:

He wrote "...and distortion a few orders of magnitude lower." so the distortion will be surely lower. Even my electrostatic design (see signature) has lower distortion (0.05% @ 450Vrms/1kHz) which is quite something considering its simplicity.

Mind sharing how you made the DIY Stax sockets?

 

[AmarokCZ]

Basically it is: 2x 3pin XLR sockets => disassemble to get 6 pins and one jack body => make 2x round PCB with six (or five for PRO jack) holes (one PCB inside of jack; second larger PCB for connecting wires) => solder all together and isolate body from PCBs and pins with thick plastic foil and isolating paint (or just any paint) = brand new "STAX Jack" 

 

[Lou Erickson]

It's the "make 2x round boards" that's the hard part, to get the layout right.
 
Way back in 2010, luvdunhill made some Stax jacks out of teflon which he cut on a CNC machine.  I know he wasn't interested in making more, as it was a hassle, but I wonder if he'd share the files for the jacks.  I have a set and they are nice.

 

[AmarokCZ]

It's the "make 2x round boards" that's the hard part, to get the layout right.

 
It wasn't hard for me - I had two original jacks and one headphone plug, so I just copied it.
I made holes in PCB according to this pic a it fits my SR-3 very well...

 
BTW ... radius 9 is just radius of old Stax Jack, those two PCBs are bigger (first ~R10, second ~R15)

 

[spritzer]

The Stax jack design Kevin did for the T2DIY (milled piece of solid teflon) has been circulated so anybody with a CNC machine can make them.  The pins are available on ebay. 
 
Quote:

With the new "poor man's amp", any idea what the distortion measurements are as yet - better than the exstata?
 
thanks
 


 

Orders of magnitude referred to the Exstata V2 no amp we'll release will have a distortion figure of 1%+.  The BATE is indeed a bit of a compromise as my goal was an amp that anybody could build.  That means a bog standard tube amp which could have been built easily in the 50's so no SS parts in the amp section.  No CCS anywhere, no LED's to set the current through the tubes or any such modern stuff.  Just resistors used for everything and, yes there are a bunch of interstage coupling caps but no output caps.  This means it will never reach the vanishingly low distortion figure of the KGSSHV but more than good enough. 

 

[kevin gilmore]

This is known to be exactly correct, and matches the original specification for the plug.
I made something like 75 of them. Maybe more. All gone now.
http://gilmore.chem.northwestern.edu/staxout3.pdf
 

 

[jaycalgary]

If anyone wants boards for the SS build at cost pm me.