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The Headcase Stax thread


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On 4/14/2023 at 8:46 PM, Kung said:

::)Ray samuels the old friend of stax mafia just released a new amplifier B-21, the electrostatic part claimed 1800Vpp voltage swing with 200mA continuous current output performance just shocked me. . . Reminds me of the horribly weak output performance of the A10 he designed before, this new amp is also questionable...

B211.jpg

What's the price on Ray Samuels B-21?   

Just to get perspective on Eletrostat/Dynamic combo amps out there..

Audio Valve Solaris $4900

https://www.headamp.com/products/audiovalve-solaris

Mal Valve Head amp three Mk 4  6000+ Euro

https://www.malvalve.de/Headamp3-E.htm

Linear Tube Audio Z10e $6950

https://www.lineartubeaudio.com/products/z10e-electrostatic-headphone-amp-integrated-amp

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On 4/15/2023 at 3:46 AM, Kung said:

::)Ray samuels the old friend of stax mafia just released a new amplifier B-21, the electrostatic part claimed 1800Vpp voltage swing with 200mA continuous current output performance just shocked me. . . Reminds me of the horribly weak output performance of the A10 he designed before, this new amp is also questionable...

 

So I've been thinking about this...  and I've seen those numbers before, 1800Vpp and 200mA.  Took me a while to figure out where but yeah... it's our good friends Apex.  See the list here:

https://www.apexanalog.com/products/linear_selector.html

Go under high voltage and see the PA194, PA95 and PA94.  All of them are rated at 900V (+/-450V so 1800Vpp if you live in magical fairy land with no losses) and 0.2A or 200mA.  Now these are absolute design limits, nominal current is 100mA and given the power limitations of each package (30W or so) there is no way you can reach them simultaneously.  This is better than the absolute trashfire of the PA97 Woo are using in the 3ES but not by much. 

Now if this is what Ray's using then the PA94 and PA95 are roughly 150$ each so a 600$ amp.  This plus a PSU and something to drive this and yeah, no way he can charge more than 4k$ for this or people will just laugh at him.  This will not stand up to a Stax 727 (unmodified even) so what's the fucking point. 

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you calculated incorrectly. lets start with $3495 for the darkstar component. and then add $6500 for the a10 equivalent.

lets just call it $10k. 

ray should be ashamed of himself for selling something less than woo audio's 23es price.

the 200ma is peak. there is no way to actually shove 200ma into the headphones with 450v power supplies. with a square wave at 20khz, the best you can do is 40ma peaks if you are using the 500v/us version.

sure hope ray is smart enough to actually use the 5.1k safety resistors, otherwise this thing could actually kill its owners if something stupid happens.

 

 

Edited by kevin gilmore
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ray maybe lies a little on the specs ??

left is 20khz sine wave, 15ma peak, bottom is 20khz sine wave 1800vppss

right is 20khz square wave 500v/us, top is current bottom is voltage, 1800vppss  

would have to be more than 1000v/us to hit 200ma peak.

only apex part that does that is the pa194, price for 4 is $1600.

 

slewrate.PDF

Edited by kevin gilmore
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Hi there, new to Head-case

I'd been out of the hobby since around 2017 and only came back in the last year

I was impressed in the past by the 007mk1 with an SRM1MK2 that a friend refurbished with updated parts. I ended up selling this setup for more portable solutions, but recently came back to e-stats with a 009 + T1s (temporary).

I did try my friend's custom tube amp at some point with the 007 and it was a night and day difference over the SRM1MK2 / 007t, so I know I'm missing out on a lot with the T1s.

Found this forum from the post about the Topping EHA5 (which I was close to getting) and came to ask about experience with Mjolnir Audio. Specifically the Tiny Triode?

Anyway, cheers

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On 9/27/2006 at 11:41 PM, humanflyz said:

I'm torn at the moment as to whether I should get a balanced [URL=https://sharpedgeshop.com/collections/japanese-knives/nakiri]Nakiri knives[/URL] setup for my complementary rig or an O2 rig? Any comments? My main setup is in my sig, I'm just looking for something different.

That's a great question! It really depends on what sound you're looking for and how much you're willing to spend. The HD650 setup is well balanced and versatile, whereas the O2 rig offers a more detailed and dynamic sound. It's really up to you to decide which one fits your needs and budget better. Good luck!

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Since this thread isn't heading anywhere... I did a little comparison between three Lambda pads on the SR-303: Stock 303 pads, EP-507 pads and Lambda Nova Signature pads.

Stock 303 pads: Detailed and airy, but shouty. Yuck.

EP-507 pads: Hmm, the shout is gone. The sound has decent tonal weight now. Note: The EP-507 is actually a bit smaller than the other two.

Lambda Nova Signature pads: No shout here either, a bit more airy than the EP-507 pads. Favourite pads so far.

I wonder if the old "303/404 shout" is actually caused by Stax's pleather pads, rather than some inherent flaw in the driver. This could also explain why the 404 limited sounds better, as it uses leather pads instead of pleather.

Edited by Tachikoma
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I'm just assuming that they're stock pads, got them with my LNS many years ago. There is a little decomposition, but its slight.

They're pleather too, but a much harder pleather. They seem a lot less permeable than the 303 pads.

Edited by Tachikoma
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The thing is, the 303 and 404 pads are made from the same material and that also applies to the LNC and LNS pads. Stax did change the material between the versions as well... the Lambda Nova pads do turn rather nasty.  I've seen a NOS unit though and the material is close to being identical.  The 307 and 407 pads were changed though, very different construction method and different materials.  Any pads with the cloth inserts are those pads. 

Now if you have dark brown pads with harder pleather, perhaps Lambda Signature pads?  I know they were fitted to Nova Signatures that came in for pads falling apart back in the day.  They last for a long time too. 

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  • 2 weeks later...
On 5/11/2023 at 8:34 PM, spritzer said:

The thing is, the 303 and 404 pads are made from the same material and that also applies to the LNC and LNS pads. Stax did change the material between the versions as well... the Lambda Nova pads do turn rather nasty.  I've seen a NOS unit though and the material is close to being identical.  The 307 and 407 pads were changed though, very different construction method and different materials.  Any pads with the cloth inserts are those pads. 

Now if you have dark brown pads with harder pleather, perhaps Lambda Signature pads?  I know they were fitted to Nova Signatures that came in for pads falling apart back in the Nakiri knives.  They last for a long time too. 

the 507 pads were very much a move back to the original pad design for the Lambda as can be seen on the prototype pictures. 

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On 5/26/2023 at 12:12 AM, spritzer said:

This thing really tops out "how stupid can we make something" and given that the iesl barely worked... I'm not hopeful this is any better given the iFi stuff is just terrible. 

Is there any hope for hybrid estat/dynamic amps? Seems like it's better to just do one very well than try to stuff both in a box.

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