EC Studio

Discussion in 'Eddie Current' started by Negura, Oct 17, 2015.

  1. purr1n

    purr1n Finding his inner redneck

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    On the chassis issues: while EC doesn't make audio jewelry (if we did, the Studio would be $20k), there are some embarrassing issues with some of the plates. I looked over our second run of plates today and to be honest I didn't like what I see. None of them were acceptable to me. For the first run of plates, 33% of them was probably to acceptable standards. I know some of you have been affected by this, and I promise you that we will take care of you one way or the other.

    There is a possibility that we may discontinue the clear anodized process and go to black painted tops which will fill in the gaps and other imperfections. These tops are thicker and heavier than the ZDS tops, and because of this, they require machining which seems to have resulted in lower quality.

    I know some of you have been totally respectful and spoke to me privately via e-mail about the chassis and Yggdrasil issues. It's OK to mention the various issues there. The more data we have the better. I don't see anything wrong with talking about this out in the open with this group. None of you guys are being unreasonable.
     
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    Last edited: Jan 17, 2016
  2. MisterRogers

    MisterRogers Ethernet Nervosa

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    Thanks Marv. Whatever frustration any of us felt around these issues, there was never any doubt that EC would make it right.
     
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  3. jacal01

    jacal01 Friend

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    I personally would like to know more about the observed disparity in output impedance between Yggdrasil production runs. Seems somewhat dubious on the face of it if the components and circuit topology has remained the same. Or maybe more exactly, marginally sufficient even among the 250 first run units.

    Have you tried multiple 1st run Yggys to make sure that they're consistently satisfactory, so that a production run dependency can be established, as opposed random unit performance differences? Have you talked with Mike or Jason about the potential non-Pro level balance line input impedance issue? Do they have a test measurement or published spec?

    As for the anodized aluminum cover plates... hell, that's just a metal supplier QA problem to push back on. ;)

    EDIT: Seriously tho, if plate machined surfaces seem to be the problem, how much more would they charge to electropolish them? Prior to bead blasting the then mirror finish, I mean... o_O But it would address the nicks and scratches from the machining process itself.
     
    Last edited: Jan 19, 2016
  4. leonardodrummond

    leonardodrummond Village idiot

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    Holy God! What have I done?! I shouldn't click into this rich thread. Eyes are hurt by $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$
     
  5. BioniclePhile

    BioniclePhile The Terminal Man - Friend

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    Shouldn't look at expensive cars either. Or houses. Or really anything that's awesome.
     
  6. Smitty

    Smitty Too good for bad vodka - Friend

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    You have much to learn young grasshopper. You think this is bad, but you haven't seen the horror that is the traditional two-channel world.
    I propose making a GoFundMe to send leonard to a high-end audio show. When the crossover to the speakers costs $10k, the studio starts to look like a good value.
     
  7. Priidik

    Priidik MOT: Estelon

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    Many sources are output z of hundreds of ohms, does the 600:600 transformer sound that much better with the low z sources?
    Some tube output dacs and unbuffered Soekris has no business with Studio then?

    You probably meant 6,15 V RMS here.
     
  8. jacal01

    jacal01 Friend

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    On further reflection, I think the source of the Yggdrasil/Gungnir Multibit incompatibility issue may be because the particular AD5791/5781 DAC chips used have a sufficiently high voltage output so that I/V conversion or signal gain is not necessary in their output buffer stage. And while this may be sufficient for driving headphone amps, which is Schiit’s target customer base anyway, the DAC buffer stage may be too simplistic or inflexible to bring its output impedance up to the 600Ω min. industry Pro level specification. The Bimbo, OTOH, has an opamp buffer stage, so that the output signal gain probably can satisfy the 600Ω min. impedance constraint demanded by the Studio’s Cinemag CMLI600 input transformer being driven by the DAC. You might try that DAC for comparison if you’re experiencing distortion issues.

    About the time that the Yggdrasil was being released, purrin suggested that its JFET buffers be augmented/replaced by a tube output buffer stage for enhanced performance capability. Since the Tribute Studio has a more neutral voice than the warmer M, it might well accommodate having an additional tube output buffer/gain interstage inserted after the DAC as a separate component, if EC is interested in such a notion. Replacing the Yggdrasil JFET output buffer board with an e.g. 6AS7 tube buffer stage is another alternative, however voiding its warranty, if that’s an issue.

    As a suitable option, I can always use my M7 multibit DAC, loosey-goosey bass notwithstanding, for driving the Studio and my speakers, leaving the Yggdrasil in my headphone trains. I have an I2S over HDMI source/DAC digital signal interconnect cause that’s in need of further celebration, anyway. ;)

    However, for retaining the Yggdrasil in one’s Studio amp setup, the easiest solution for the impedance mismatch is probably to run the DAC output through a preamp, or in our case a capable headphone amp, for further input into the Studio. I just hope that I have a suitable headphone amp RCA or XLR analog output available. <insert fingers crossed icon here>

    I’m still in.
     
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  9. Smitty

    Smitty Too good for bad vodka - Friend

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    Well, at least the analog boards are upgradable. Maybe Schiit will release an improved version that will solve this issue (and maybe it will be tube based, though I wouldn't hold my breath for it).
     
  10. Griffon

    Griffon 2nd biggest asshole on SBAF

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    I wholeheartly concur. The headphone business, though already outrageous, is still far from the traditional 2-ch insanity, and cable voodoo in particular.

    http://www.hifiheadphones.ca/audioquest-fire-rca-audio-cable/

    Some meters of cable voodoo? Or buy a EC Studio? The answer is just self-evident.
     
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  11. jacal01

    jacal01 Friend

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    Don't you know that the trick around here is to buy the reference amp and the cables? Especially now that I need yet another pair to run between my Krell preamp/HP amp and my Studio.

    Go big or stay home.
     
  12. Judeus

    Judeus Facebook Friend

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    couple questions...

    1. what kind of speakers can this drive exactly? 6w @ 8ohms doesn't seem much at all (total speaker noob...)

    2. Is this balanced in balanced out? Or balanced in single ended out? (is the xlr on the front just for convenience)
     
  13. Smitty

    Smitty Too good for bad vodka - Friend

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    It should be able to drive bookshelf or monitors for nearfield listening if they're not mini Maggie's, and should be good for stuff with sensitivity higher than [email protected] m. Speakers are funky, so it mihlghtvbe better to consider 94 dB as the sensitivity go aim for. @purrin will need to comment on the topology.
     
  14. Griffon

    Griffon 2nd biggest asshole on SBAF

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    I'm not sure if you're talking sarcasm or you're serious all-in about cables. FWIW, I found cables have the poorest value among audio components.
     
  15. insidious meme

    insidious meme Ambivalent Kumquat

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    I'll take "sarcasm" for $200, Alex.
     
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  16. Smitty

    Smitty Too good for bad vodka - Friend

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    It's sarcasm, most of us are pretty shameless about magic cables and such.
     
  17. jacal01

    jacal01 Friend

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    Delivery scheduled for Friday: #6 Cannonball!
     
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  18. MisterRogers

    MisterRogers Ethernet Nervosa

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    Ok. I reached out to engage EC & Schiit a couple of days ago. All stepped up to sort this out, and here's the definitive explanation of what's going on. Rather than translate, I'll drop in Jason's relevant statements for the benefit of all those affected by this (Yggdrasil / Gungnir Multibit / Studio / Balanced). These statements are in chronological order:

    Jason:
    "I looked up the Cinemag line. If the Cinemag is indeed a 600 ohm input impedance model, it looks like there’s no problem with voltage overload. The problem is current drive requirements. For Yggdrasil’s 4V RMS output (22.4V p-p), that's 18.7mA peak. The output buffer can’t provide that much current, nor can it be simply re-engineered to do so. It would take adding a separate push-pull output stage on to the buffer, and a re-examination of the current transformer’s capability to provide the additional 120mA current at 48V (4 buffers per balanced stereo pair, plus the same output stage added on the SE summers) if we want SE to drive that load as well. Nor can we reduce the output level easily, since that’s set by the voltages running into the DACs, which are specific to the design. Passive dividers might be usable, but the amp would have to provide enough gain to compensate.
    So yep, looks like 15K is the way to go. It would only require 0.75mA of output current, which is well below the envelope of the current buffers. Sorry, but I don’t think we could even power the additional output stage without major surgery and architectural changes, let alone what speculate what it might do to the sound."

    "Distortion I believe, because even 9.3mA is outside of what the buffers'—or summers'—envelope. As to why some people aren’t experiencing it, I’m not sure. There is some variance in the current through the buffers (typical of JFETS), but even on the hottest side, they aren’t running 9.3mA. To remedy the distortion, we are either at complete re-engineering of the Yggdrasil (probably down to transformer and choke level) or 15K input transformers on the Studio. Has anyone tried the 15K input transformers?".

    "Yep, 600 ohm driving capability ain’t gonna happen. Confirmed it with Mike in a talk last night.
    Everything else—10K, 15K, no hum, etc…that’s fine."


    While Jason was addressing Yggdrasil, experientially this seems to apply to Gungnir Multibit too; though Gungnir Multibit seems to swing a bit more current, as it distorts less. All of this pertains to the balanced inputs, or SE inputs too if the balanced inputs are loaded up (cables are connected). SE is said to work without distortion if the balance cables are disconnected. I'll verify this when I get home tonight.

    Summary: If we want to use Yggdrasil / Gungnir Multibit with T Studio balanced, we'll need the 600Ohm transformers swapped out for the 15K transformers. My goal with all this, was to try and directly engage both companies to definitively identify why it wasn't working. So now we know. I appreciate Jason, Mike M, Craig and Marv's willingness to engage and dig in to this.
     
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  19. TMoney

    TMoney Shits on SBAF over at Head-Case to be cool

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    What are typical input impedances on amps? Is 600Ω (for balanced or unbalanced) a typical number?

    My preamp's output impedance via balanced is 1,000Ω so I'm guessing it wouldn't play well with the Studio with its current 600Ω input transformers?
     
  20. fishski13

    fishski13 Friend

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    typically, a preamp/HP amp input impedance is defined by the parallel resistance of the pot/attenuator and first input stage, usually 10s of Kohms with consumer audio. my Klone is at around 10K or so, on the lower side of typical for consumer audio. never an issue with sand output DACs like Schiit, but could cause flatulence from a tube output DAC depending on the output impedance and current capability.
     
    Last edited: Jan 27, 2016

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