The Headcase Stax thread

[mwl168]

Interesting. 

My North America, black SR007 purchased new in early 2015 also has a SZ3 serial number. 

[wink]

8 hours ago, johnwmclean said:

Thanks guys that’s a relief, my serial is SZ2 - 2301, the box is minty fresh and headphones are immaculate, they sound darn good too...  

What happened to "There can only be one headphone"...?    

So now there's only one SR-007 and one SR-009                     perhaps..... 

[spritzer]

I've had at least five 007A's that were SZ3...    Stax serial numbers, such a source of joy. 

[coptician]

Hey everyone,

I'm looking for some new pads and a new head band (the flexible part, not the rigid outer bits) for my SR-007A. It's a brown/champagne one. I can't seem to find any place that has the head band in brown. Does anyone know where I can get one? I'm in the Netherlands, which might complicate matters...

[Ali-Pacha]

My experience with electromod is they always get the parts eventually. I assume you've asked them for brown headpad availability...?

Ali

[Tinkerer]

Hey coptician, if you still have your old headband, don't toss it out when you get a new one. I need the plastic mounts off of it. Shoot me a PM with what you want for it.

[coptician]

18 hours ago, Ali-Pacha said:

My experience with electromod is they always get the parts eventually. I assume you've asked them for brown headpad availability...?

Ali

Yeah, I sent them a message, thanks! They're checking, but it sounds like they think it's unlikely any brown parts are available from Stax anymore.

18 hours ago, Tinkerer said:

Hey coptician, if you still have your old headband, don't toss it out when you get a new one. I need the plastic mounts off of it. Shoot me a PM with what you want for it.

Thanks for the offer, but I think I'm going to keep the current one as a backup in case something goes wrong. Having spare parts for these 'phones makes me feel a little more secure.

[spritzer]

I just loved to see the inside pics of the "best electrostatic amp in the world" over on HF, the QA Jecklin Transdyn.  So it's a badly built EQ board with a B&O IcePower 125ASX2 power amplifier module and a couple of cheap looking transformers.  Also locating those two transformers side to side... yeah there will be some crosstalk. 

Edited October 9, 2017 by spritzer

[GeorgeP]

Am surprised he actually posted these pictures instead of falling into a deep depression after realizing he paid thousands for it...

[kevin gilmore]

The volume pots are likely to be linear instead of log because one pot spins the other direction due to the gears

2 active bandpass filters per channel and 3 compand/expand per channel. Lots and lots of signal thru those electrolytics.

So maybe an attempt at a near field equalizer?

$4k euros for this.

very sad

[spritzer]

To take this pics and post "best amp evah!!" shows a special level of something...   

Some things stand out for me, the total lack of heat shrink on the mains switch which means the CE rating doesn't stand up to scrutiny.  Also just the sheer level of hacking going on.  Parts suspended in mid air and other marks of quality.  Also just the general lack of giving a fuck... 

[wink]

But....   but...... it "works"           well,   sorta......   

Besides, some people love it.  That's gotta be good, right....?  

 

[stator]

i was listening couple of months ago to QA Transdyn at thinkers place with SR-009 and SR-007MK1,it was overall excellent sound ,some sort of meaty/warm detailed presentation with lots of power.Other people who heard it liked it quite a bit.I have been at he's place many times and heard lots of different stat amps and this is one of the best .Phenomenon phones are already in third generation and are coming in next month from Russia ,i will report something about them.

 

[sorenb]

31 minutes ago, stator said:

i was listening couple of months ago to QA Transdyn at thinkers place with SR-009 and SR-007MK1,it was overall excellent sound ,some sort of meaty/warm detailed presentation with lots of power.Other people who heard it liked it quite a bit.I have been at he's place many times and heard lots of different stat amps and this is one of the best .Phenomenon phones are already in third generation and are coming in next month from Russia ,i will report something about them.

 

did you ever listen to a Stax SRD7 ? that will probably provide you a similar enjoyment

[spritzer]

First off, anybody who plugs anything Stax into that box deserves the Darwin award, plain and simple.  Going by that the new Floats are supposed to be compatible with the old ones we are dealing with a bias of +1500V... yeah...just about three times that of the Stax.  Maybe they lowered it but I some how doubt it as those drivers need a lot of bias to work.  That "Thinker" (the irony is palpable) states over and over again that the bias is 800V but how was that verified. Perhaps by measuring after the (32M) ballast resistor? 

Then we have the transformers, Stax used a ratio of 1:25 but Jecklin...1:120.  So, even with a low input you are overdriving the fuck out of the Stax.  I guess that is one way to get a "meaty" impression...

[mypasswordis]

I would be interested in seeing what equal loudness curve the EQ circuit is based off, and how close it actually gets. This is something I definitely want to try eventually, but in the digital domain because the cap farm is just stupid.

[kevin gilmore]

more than just an equalizer, there are 3 companders/expanders in there.

so something like a stax ed1 plus a dbx3 (or possibly 3 band equalizer each feeding a compander/expander)

for those not familiar with dbx... this thing

http://www.ebay.com/itm/DBX-3BX-3-Band-Dynamic-Range-Expander-PARTS-OR-RESTORATION-ONLY-/202076549539?hash=item2f0cb371a3:g:T1IAAOSwm9tZ2pji

one of the pictures over there shows the bias board partially populated, so the bias might be as low as 600v, who knows

Edited October 10, 2017 by kevin gilmore

[mypasswordis]

Interesting.... just googled a description of what it does here: http://www.just-hifi.com/New-Jecklin-Float-QA_10441524-34.html

The ED1 is for diffuse field equalization, I think this one is doing equal loudness compensation just for some curve that corresponds to 8dB down, along with the dynamics expansion. Ideally the compensation should change with volume. 

Edited October 10, 2017 by mypasswordis

[JimL]

Yes, I think they are doing a baseline EQ for 8 dB down, then varying the compensation with volume to match the Fletcher-Munson, Robinson-Dadson or some other equal loudness curves, plus adding in some expansion, but the variation occurring separately in three frequency bands, possibly depending on the loudness within each band.  At least, that's what they seem to be saying - or I could be completely off base.  Hard to know from the vague description, and I have no idea what sort of psychoacoustic research they have to back it up, if any.

[wink]

... and, here, I thought this was Psychoacoustics.....

 

 

[Jensethi]

Hi everybody
With all the new electrostatic amps popping up I am wondering what the STAX-Mafia thinks about this 
https://ifi-audio.com/portfolio-view/pro-iesl/

[JimL]

Not a member of the Stax mafia, but...it's a glorified SRD-7 in a fancy case.

Edited October 13, 2017 by JimL

[HemiSam]

This should be entertaining...

HS

 

[Pars]

Appears to have the usual items necessary to generate hype:

1) fancy case - check

2) bullshit bingo laced ad copy - check

3) high price (so you know it's gotta be good) - actually not too bad at $1400

 

 

 

Sent from my iPhone using Tapatalk

 

[dsavitsk]

$1400 seems high for $80 worth of transformers.

On 10/9/2017 at 4:58 AM, spritzer said:

Also locating those two transformers side to side... yeah there will be some crosstalk. 

Doubtful. But even if there is, there will be considerably more across your head.