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arnaud

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Everything posted by arnaud

  1. I was pretty shocked to see these pics of a disassembled unit, takes some courage 😅 These are assembled in a dust free environment so I wouldn’t recommend disassembling these things like one takes an engine apart for cleaning. On to the sound, I found these lacking a bit of excitement when fed with T8000 amp and assumed they need oozes of power, like a carbon for starter. The mesh stator appears to drastically damp out the mid / highs (not to the point of having a blanket between the driver and the ear as sometimes seen in planar designs though 😵‍💫) relative to the 009, which will appeal to many.
  2. arnaud

    Kaldas Research

    Hi Aumkar, This is an interesting development and I am curious about how you came up with some of the design aspects. For instance, we can see that the open back baffle is quite deep and has non symmetric shape. Does this measurably affect the response on your kemar? Also, my recollection of 009 measurements is that is has ~80Hz resonance frequency loaded (~150Hz in free air) with a non-ported design. How about your prototype? From the measurements you published, it looks more like a ported design with ~45Hz resonance frequency? I'd be keen on making acoustic simulation of the housing + ear pads if you are willing to share this information, cheers, arnaud
  3. I don’t have much to add to hugo’s post, agree on the findings except perhaps sounstage which felt a bit more closed in on the 009S compared to 009. I also used my source (sony dap) HP out to drive the T8000 so it wasn’t ideal + noisy environment but I was pleasantly surprised by 009S. These days I am applying dig. EQ to my 009 to take the edge off the mids and boost the subbass a little so I did not think I’d get into the 009S. But what I listened to today was quite promising, the 009S improves on the 009 across the board and I could not find a drawback. It sounds cleaner, fuller body, more natural mids, looses that tendency of 009 to sound thin / agressive at high volume levels and does not loose any treble extension or resolution. I think this one is going to be popular with the mafia given the number of 007 fans and 009 haters ;-). Design wise, besides the official blurb on housing, stators and grill, the pads felt definitely stiffer than the 009 and I bet part of the chances in voicing come from there (perhaps more so than the gold plating of the stators). The 009 really do sound cleaner than 009 from bass quality to transparency overall, the structural redesign of the grill and such may be more influential than I would have thought. It was good to see Sasaki-san there (apparently the head designer Suzuki-san is joining tomorrow) but the new generation of employees seem to be on top of the game already so I can only wish a bright year ahead for Stax. Besides talk on the 009S, Suzuki-san mentionned all D/A related designed are outsourced to edifier (the new portable dac amp fully is), the upcoming dac board addon for the t8000 also won’t come out of Japan (they stick to analog components design). Apart from that, Edifier still leaves Stax full autonomy today it seems.
  4. Interesting tear down, thank you Birgir! The driver is effectively sandwiched between the housing the baffle plate through these rubber gaskets, quite different from Stax hard fixation style. Also, the wire mesh of the stator seems very very fine, that's interesting because I bet the airflow resistivity is actually orders of magnitude higher than than traditional perforated stators (that present little airflow resistance contrary to the common belief these days...). That fine wire mesh, ignoring the mechanical aspect for now, must certainly add significant damping to the diaphragm. As for the price drop, it's hard to imagine the SR009S release had no influence on that ;-) arnaud
  5. The worse part is that these comments made me curious and... so basically, woo wes and earpods is all you need, the rest is to show off and, by the way, I am spending 50 grands on a headphone system where the tubes raise up when you turn the amp on, I am thus done with audio. Finally someone who got it, it was about time. Back to you gilmore, building those carbons with burger. arnaud
  6. This is what Suzuki-san was saying in his video I think: DC coupled not strictly because of the use of servo.
  7. Suzuki-san confirmed this was for dac or phono board when I talked to him at the show. You should have asked me that before, I would have brought it up! Also he confirmed the dedicated low voltage supply for the addon board. Jude got other things confirmed when he visited Stax office on Friday (such as power supply regulation), I hope to see some news posted in the HF thread at some point. I liked what I heard on brief listen when compared to stock 727 amp, it felt more significant than differences between other stax amps. Of course, this is to be taken with a pinch of salt given the short audition / show conditions etc... Oh, and it does look very nice in person, sand blast finish on the aluminum panels, reminiscent of the SR009. It's bigger than other stax amps but nothing compared to my BHSE, I can see people wanting this. Arnaud
  8. There you go, I stand corrected. Now, if I only knew what this servo regulates actually ;-).
  9. From the little I understood in the video, slot 4 is for addon that are still in developments. Suzuki-san (chief designer) specifically mentioned about DAC or equalizer (phono that is?). He also mentioned this line 4 slot has its own transformer / supply, independent from the rest of the circuit. He mentioned great attention had to be paid to shielding giving how closely spaced these components are and the mixture of low level signals (including upcoming slot 4 boards) and 60dB circuit (or 54dB I forgot). So, encaged toroidal, encaged inpu stage tubes, encaged slot 4 board... Seems like a big effort just to make this all fit in one box to limit manufacturing / shipping costs and all. Oh, another thing he mentioned which flew over my head is presence of a servo (world first for stax) to make sure the amp operates within spec from cold start. Otherwise, you'd have to wait about 1h till warmup because of thermal drift. Hopefully I did not get this wrong but the heatsinks used for the SS output stages are face to face with close spacing to make this thermal drift uniform across channels (or differential signals?). I let the experts decipher and correct this ;-). Not sure if I'll have the patience to wait in line but I may be able to see it irl this w.e. arnaud
  10. He is afaik, think the main bottleneck was efficiency but I suppose the delayed launch has a bit to do with him working on this.
  11. There was talk of something mk2 becoming something mk3 but I personally don't see the Omega 2 getting the treatment this time if it was already tweaked behind the scenes (pads) per people claiming current production Z3 are good. On the other hand, I recall Stax acknowledged the tiny SR003 could be more ergonomic so there's hope something is being done there. But indeed, nobody has a clue what will get released or when... arnaud
  12. Stax amp coming this summer, sitting above the 007t2 but not quite T2 grade. My random guessing goes toward something similar to the kgst with sr009 price tag... Other than that, you pissed off the sole speaker of transdyn.... arnaud
  13. Hifiman RE-2000$ ;-). There you go, the only mistake with the Edition-6 was the unfortunate naming, should have gone by HE-6000$. BTW, HE-9000$ is coming soon at CanJan event near you ! arnaud
  14. An attempt at translating the latest Stax tour / interview: http://www.head-fi.org/t/829843/stax-sr-009-and-t2-successors-confirmed-for-spring-2017/45#post_13130037 cheers, arnaud
  15. Correct, I think this was just the excitment to post big news while relying on google translate ;-). Now, what could 2018 big thing be if the amp is released next year?! A new ... ladder DAC? ;-) arnaud
  16. His account must have been hacked!
  17. Clearly, the best action plan here is for birgir to do his best and help this fellow actually burn through 10 pairs of sr009. When you see 2kUSD cables popping for 4kUSD utopia phones and takers, that will be a nice change as the cable work here should be cheaper than 10 pairs of drivers, a good deal.
  18. Does not seem so as one headfi report from rmaf mentions it has a tough time sounding more full bodied than a mere sr207... Maybe there was a 1 decimal error in the yuen / usd conversion? arnaud
  19. As discussed privately with @PretentiousFood, assuming spice circuits exists for many of the amps discussed here, wouldn't it make sense to have standard results from a spice simulation for 120pF capacitive load and various voltage swings? In terms of V swing, I don't know how load you listen to but, in my case, I seldom seem to exceed 100V PPSS. Something like 80V, 160V, 320V, 640V, 1280V PPSS would seem sufficient. As I understood from spice simulation, the output current vs. frequency don't show actual current limitation of the amp (e.g. 6mA in example shown above) but transient simulation would? Similarly, we could have thd vs frequency at same Vswing levels. Seems like that would be more suitable than just talking from the plate current, rail voltage specs and topology when comparing these various amp designs. Arnaud
  20. Birgir, So, for you, main issue with the SR009 is the lack of top end extension on all amps prior to the carbon including the T2? About measurable performance, give me a break. The 207/507/L500/L700 sound clearly different yet we can't tell fuck from looking at the measured FRF such as the pretty clean measurements Tyll makes at InnerFidelity. About the BHSE responding to tubes, or lack thereof, you can call people fool all you want, there's absolutely no question it sounds subtly different when switching tubes, including the midrange where it's pretty sure you won't find a measurement method to highlight the differences. I never bothered trying to measure because, heck, even less subtle differences between shades of lambdas don't easily show up in measured graphs. For the SR009 in particular, it really does quickly sound shouty in the BHSE with production tubes (hyped chinese crap or else). As I recall, you listen at pretty healthy levels so I can bet the 009 sounds like torture for you. You can despise all you want the likes of Mulveling or Purk, these guys have, ime, a pretty good track record at discerning good from bad sounding stuff and I often find I jive with their experiences. Yours, no offence but, not much. That does not change anything to your brilliant engineering skills but, at least for the subjective part, you'll have to excuse some of us if we don't quite hear the same greatness and faults as you do... arnaud
  21. Wow, I have to admit I would likely have fallen for this. This is so much more subtle than the nigerian deals ;-). It's great to this posted here, probably worth a sticky thread though. Also, hoping the fellow who had his bank account and personal address posted here is really a scammer... arnaud
  22. arnaud

    Deals

    I am really getting itchy about getting some ER4SR or XR. Not quite the deal starting from nothing but I have grown sick and tired of my crappy bose ANC earphones. They isolate great and are comfy but that really is it. Built as great as every other pos Bose makes, that is one of the drivers rattling during heavy when under stress from anc circuit, iPhone controls busted after a few months etc... I'd rather listen to my apple EarPods than this if it wasn't for the isolation. I tested ER4P (I think) and thought it was a bargain in the midsts of 1kUSD iems. 3 years later I think the average price fotm iems is more like 1.5kUSD to 2k so that makes me even more tempted to just go the single BA old-fashioned way ;-).
  23. To me, it seems like the main intent is to create a new ecosystem of phones and amps that don't mix with Stax stuff (and accessorily work around inefficiency issue of current ether E design). I am too close to Stax to be neutral but I don't see MrSpeakers running circles around good old Stax with this. The L700, I feel, is stunning for the price and sounds great out of budget amps. It's thus not an issue of cost and I don't see a new plug changing this. Now, if we're talking about heavily sponsored brands on head-fi that would be given massive exposure for new amps / phones and this special club new plug, I can imagine though that there will be a crowd for this. Not the old farts like us that is... Actually, reading the posts of stillhurt and the likes, it's like they really really welcome something that's not compatible with stax. Meh, head-fi these days... arnaud
  24. This new plug idea makes no sense to me. He's blabbing about the need to come up with cheaper amps affordable to all, yet better performance than Stax offerings. But, how can a new plug design make this any cheaper. Also, AFAIK, it's not like Stax is ripping off their customers with current pricing so am not sure what can realistically be expected from non-Stax commercial offerings. The Ether E prototype shown in Tokyo a couple months back was utterly inefficient (LLmk2 at max volume to get decent loudness from a bricasti M1, BHSE at 3-4PM!). My guess here is that Dan will find someone to make non-direct drive amp with high voltage gain transformers (and/or high bias) to drive his Ether E, hence he does not want to use a Stax plug to avoid people frying their Omega phones when trying to A/B out of same amp... arnaud
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