The Headcase Stax thread

[spritzer]

It's a SRX based amp with probably an added phono stage.  It's a good circuit but the modern ESX version is so much better. 

[dreamwhisper]

I was able to pick up an Sz1 Omega 2. Serial #1880.

Is a 'bad' O2 Mk1 still a good sounding headphone? Reading some of this Sz1 hate worries me.

[spritzer]

Yes, it's still good. 

[DefQon]

Interesting:

 

http://www.faqs.org/patents/app/20140064510

[nemomec]

Don´t spend your money for a BHSE and don´t make a long journey of searching a SRM-T2! Its so easy take a Audiovalve RKV and a Verto Box and all is fine! 

 

http://www.ebay.de/itm/VERTO-Stax-electrostatic-dynamic-magnetostatic-transformer-headphone-transformer-/171460930132?hash=item27ebde2a54

[DefQon]

Already been posted, not sure if you're being serious or sarcastic.

 

But both Spritzer and Kevin have done this (with better quality transformers) in the past and both have posted there lengthy discussions why it's never going to be an optimal solution compared to a proper discrete and dedicated e-stat amplifier.

 

Seem's that Eric is shilling the crap out of the RKV stuff and now this energizer on head-fi and Kevin has posted his technical counter-arguments why that energizer is an overpriced piece of crap that does the same thing a $150 SRD-7 energizer does Stax made over 20 years ago.

[Ali-Pacha]

There is no such thing as bad publicity.

Ali

[spritzer]

Here is a good article on the awesomeness of the Verto:

 

http://hifipig.com/audiovalve-verto-and-rkv-mk-3-headphone-amplifiers/

 

So it basically doesn't work and I can't say I'm surprised.  I've seen a lot of takes on the self bias idea over the years but this one is by far the worst.  As one would imagine, to get +580V bias off the music signal would require some step up to help matters when the audio signal is low.  No such luck here, just a huge voltage multiplier with all the issues they have and a pile of parts needed for it to work... or not as it happens.  I built these:

 

 

...and they worked perfectly off a portable headphone amplifier and fit into the palm of your hand.  Me thinks the person responsible for the Verto hasn't got a clue how to do this properly...

 

As for the subject of transformers, it's been well known since the dawn of electrostatics that they didn't match well with transformers.  Look at the history of brands like Sound Lab and Acoustat who spent a lot of time to make the transformers less of a crippling weak link in the performance of the panels.  So many different designs have been attempted over the years but none have truly worked and the inductive nature of transformers and electrostatics don't play well together.  For speakers they are a necessity given the very high voltages (Soundlab are up to what now, 20kV bias) but for headphones we can run on +/-400V and overdrive the transducers so amplifiers are a no-brainer.  

 

A word about just how stupid eric65 really is.  I mean this is epic shit and he just can't figure out how moronic this really is.  His great mod is to bypass the shitty transformers of the Woo WEE as according to him the gain is too high.  Granted 1:50 transformers are a bit too much today and the iron Woo is using is wholly unsuitable for the job so good riddance.    What Eric does though is he drives the Stax directly off the TRS plug on the RKV... wait for it.... single ended that is.     - stators are grounded so there is at least that but we are talking about distortion close to the 20% mark and at very low volume.  The theoretical max voltage swing of the RKV is 200Vpp but in reality it will be lower and we all know how great amps are when running right on the limit. 

[Ali-Pacha]

I've no interest in this transformer box since I already have two SRD-7/SB (mk1 and mk2). Sound is nice, especially with my vintage sets, somewhat foot-tapping because of mids-hump, but it is no match for a basic SRM-1/mk2 pro : details retrieval, extension, soundstage, dynamics, bass tightness, etc...

 

I don't have a clue in electronics, but I'm convinced the amplifier path is the right one for e-stat headphones. At least because Stax driving units are now amps only.

And though the mafia points out some "flaws" (unregulated PSU, overdriven tubes in 007t, no feedback on 727's last stage, etc..), most of them because these units are built to a price point, I do think they are great value for the money. And the build quality is quite there.

 

Last but not least, I'm on the list for a BHSE ( #4 batch), because I'm convinced this is the endgame commercial amp for Stax phones today (and it's amp-pr0n to look at ). And please kill me without mercy whenever I complain about the waiting time.

 

But Birgir, let's face it : this Verto unit didn't work because it was damaged. And it has more likely something to do with the build quality the reviewer points out.

 

Anyway, your little SB boxes are appealing. Could a basic O2 amp feed them ? 

 

Ali

Edited September 15, 2014 by Ali-Pacha

[Ali-Pacha]

Time for fun fact.

 

A step-up transformer box called "Verto" already exists. Built by Ortofon, for MC phono cartridges :

http://ortofon.com/hifi/products/transformers/verto

 

One more thing : transformers inside this box are lundahl's. Could this Verto box have mafia's approval ? 

Ali

[spritzer]

I doubt the verto was damanged, the reviewer just didn't listen loudly enough to energize the bias supply.  Even Eric has said there is no sound for the first two minutes which is not good for the health of the diaphragm. 

 

Those small boxes worked just fine off a Grado RA-1 (normal version) driven by an iphone. 

[Ali-Pacha]

Nice. And black. Like your next mini KGSSHV 

 

Ali

[spritzer]

The next ones will be silver as they are just waiting for transformers.  After that there will be two black units... 

[purk]

 

 

 

 

Birgir...you probably wonder the where about of your transformer boxes.  They are actually with me courtesy of Doug.  I'll revisit them again with the SR009.  The SR007 didn't work all that well with them due to its much more difficult to drive nature.

Edited September 17, 2014 by purk

[spritzer]

Yeah, the 007 will not work well with them but the SR-X Mk3 Pro worked pretty well, same with Lambdas.  You can confirm though that it is possible to build a small Stax transformer that fits into your hand and actually works? 

[purk]

Yeah, the 007 will not work well with them but the SR-X Mk3 Pro worked pretty well, same with Lambdas.  You can confirm though that it is possible to build a small Stax transformer that fits into your hand and actually works? 

 

Yup...amazing work indeed Birgir!

[arnaud]

You guys don't get it, do you? The rkvertose will soon take over the world, we're dooooomed!

[spritzer]

Fuck!!!! 

[Ali-Pacha]

May I post some BHSE pr0n, instead ?

Ali

[purk]

Whoa...no more of the original stax jacks?  Pretty darn nice!

[Ali-Pacha]

I've asked Justin about it on HF. Whenever you don't have any allergic reaction to HF, you may go there and read the details 

Ali

[spritzer]

The BHSE used to have the WPI sockets and only a handful had genuine Stax sockets.  Mine is one of those... 

[justin]

That was before Stax successfully put an end to 3rd party amplifiers

Sent from my iPhone using Tapatalk

[spritzer]

...or those of us that hoarded Stax sockets. 

[Mario_Fpolis]

I used to have a SR303 + SRM212. Loved it for female vocals, strings, soft jazz. Not so much for Led, Rush, Purple and fusion. Fast, coherent, but lacked bass presentation. Could not ask too much for such a simple setup, nonetheless, I know.

 

In the end, sold it in order to get some better dynamic phones. But still in love with electrostatics.

 

May I ask something? How about the actual 007 for 60-70 rock and fusion, that I listen most of the time? Does it do a fair job, like presenting a grooving sound, good bass, as in on pair with dynamics?

 

I do not have the time or patience to look for a mint Mk I, since I live in Brazil and to send a used phone to here is so troublesome, not to say expensive, pretty expensive. It would be like go to US in a near future and buy a new one and ship to my hotel.

 

What do you guys think? Birigir, let´s start the season of trashing newer 007 versus older and better 007 Mk I.

 

Many thanks.