Oh Sh#7! Eddie Current Studio B

Discussion in 'Headphone Amplifiers and Combo (DAC/Amp) Units' started by purr1n, Aug 15, 2020.

  1. atomicbob

    atomicbob dScope Yoda

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    TRS jack has a common ground which shares the return currents between amp and headphones.
    The 4-pin XLR has independent grounds and thus no co-mingling of return currents.
     
  2. atomicbob

    atomicbob dScope Yoda

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    Studio B is one very special amp. I've listened to many of EC 2A3 amps, but never was excited enough to acquire one. I've also heard a number of 300B amps (not EC) and was similarly unmotivated. Craig's 300B is a wonder amp, at least for my personal preferences. Like you, I wish there were more hours to enjoy.
     
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  3. totlsota

    totlsota Rando

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    StudioB is my 1st transformer-coupled (non-OTL) headphone amp. I've had a good sampling of nice OTLs and the SB has a different flavour. I can't quite label it yet. Perhaps the OTLs are a bit more dreamy/smooth (blurred transients) and less well-articulated than the SB. The staging on the SB is something and the mid-bass can be quite a force. Now I need to find some efficient speakers worth pushing with this thing...

    My tube-rolling days are a thing of the past, however, I'm using a pair of Emission Labs 300Bs and it was suggested earlier in the thread that they are a bit more "solid-statey", so I'll have a pair of JJs to compare with soon.
     
  4. purr1n

    purr1n Super Friend

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    It's the output transformers. They say output transformers make the tube amp. My custom 45 amp is using the same output transformers as the Studio B - the difference is that I'm running 45s (and interstage transformers instead of caps). Two 45 tubes are needed because their plate resistance is twice the 300B. I can say that the OPTs influence the sound more than the tubes (300B vs x2 45) - much more than I expected. This amp sounds quite different from my prior custom 45 which used exotic double C-core Lundahls.

    I don't know if you had ever heard the Balancing Act. I think you would have liked the BA. For time until the Studio B, Craig was tending toward a drier, clearer, more neutral sound of the Cinemag OPTs along with the tertiary winding. A lot of people really liked this sound; however, I tried to steer him away from this for years. Studio B completes the circle back to the days of the BA sound. The tertiary winding remains, but I've noticed the feedback from has peeled back. This results in the best of both worlds: the bigger soundstage, more lively, more engaging, and richer timbre of the pure NFB designs along with tighter bass, lower distortion, and less goo. Craig finally stopped being a cheapskate after dozens of customers asked him to replace the stock interstage cap on the AF with a Jupiter, so the Studio B comes with a Jantzen Superior.

    The Studio (Tribute+Cinemag) and AF (Cinemag with the feedback) I preferred with Audezes, stock HD650s, darker cans, etc. (and with warmer or laid-back DACs). The Studio B I prefer with the Focals, HD600, etc. (and with neutral DACs).
     
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    Last edited: May 30, 2021
  5. wenbinbin2010

    wenbinbin2010 Rando

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    Rando lurker here finally posting in the new member thread. I've been a lucky owner of an Eddie Current Studio Jr and have really appreciated all the information from these threads on SBAF. Don't have too much of my personal contribution other than I think the Gold Lion 300Bs and the WE 396A square-getter are an excellent combo. I've had this setup paired with a HE1000se for the past several months, and it's pure audio bliss every time.

    My one question that has been bugging me recently though: is there any way to make the amp from outputting via 1/4" and XLR when the amp is switched to SE mode? I was hoping to keep two different headphones connected, but whenever I listen via the SE output, I have to unplug my headphone (HE1000se) plugged into the XLR out. When it's switched to balanced mode, this isn't a problem as there is only sound output from the XLR out.
    Thanks in advance with any advice or thoughts!
     
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  6. Boops

    Boops Friend

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    I'm thinking of experimenting with biamping the Studio B and want to make sure I'm thinking of this in the correct way. Is the diagram below the right way to approach this kind of setup?
    • Studio B speaker outputs go to the HF speaker inputs
    • Studio B line-out goes to a Goldpoint attenuated to -22 dB (offsetting 22 dB gain of Amp 2)
    • Goldpoint output goes to Amp 2
    • Amp 2 speaker outputs go to the LF speaker inputs
    • Studio B controls all volume

    biamp-diagram.jpg

    @purr1n or someone else who has done it: does this look right to you?
     
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  7. Armaegis

    Armaegis Friend

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    @Boops If the lineout doesn't have any gain attached to it, then you'll only need -7 dB on the goldpoint.
     
  8. purr1n

    purr1n Super Friend

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    ^ what he said.

    The cool thing is that the Goldpoint now acts as a low/high tone control. There could be a possibility that there isn't enough granularity with the stepper. I've gone cheap and used Sys.
     
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  9. atomicbob

    atomicbob dScope Yoda

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    This looks like a job for Measurement Man.
    But he's out to lunch so I'll answer.

    1) Studio B is specified as 1.5 V in to reach 4W out at 8R load. Calculating 4W at 8R requires 5.66 Vrms.
    5.66 / 1.5 = 3.77 for gain factor or approximately 11.5 dB

    2) at maximum volume I measure a gain of 8.3 dB on my Studio B with Genelex Gold Lion tubes
    3) at maximum volume setting the line I observe 1.5 dB gain at line out

    This implies approximately 7 dB gain at speaker output compared to line out to use in your calculations.

    Next consideration. Does the HF and LF sections of the speaker have the same sensitivity? It is possible they are different and the internal crossover has accounted for that difference. If the sensitivity between sections differ you will need to account for that between the two amps.
     
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  10. murray

    murray Friend

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    Another approach would be to use pink noise, either by ear or measurement mic. As long as you have sufficient range of adjustment.
     
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  11. AdvanTech

    AdvanTech Friend

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    Does much change for a 4R load?

    The crossover sections for HF and LF should be the same sensitivity.
     
  12. Boops

    Boops Friend

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    I’ve got a 47-step Goldpoint which can adjust in 1.5dB steps, but I also have a Sys lying around.

    @atomicbob does the 7dB difference you’ve measured for ECSB mean that, assuming 22dB gain for amp 2, the correct attenuation would be -15dB, not -7dB?

    (and ignoring differences in sensitivity between HF and LF, divergence between manufacturer stated gain and measured gain for amp 2, etc…)
     
  13. atomicbob

    atomicbob dScope Yoda

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    I don’t know. I didn’t test a 4R load. The manual states 4W for either 4R or 8R load.

    That is correct.
     
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  14. Boops

    Boops Friend

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    Thanks for the recommendations. Tried this out at @AdvanTech's place with his 3WC-15s with his Allnic integrated on bass duties. It was nice to have a numerical starting point with the measurements (thanks @atomicbob), but ultimately we had to dial in the correct bass level by ear. It was not hard with the precise 1.5 dB steps on the Goldpoint 47. Within about half a song, we had it sounding about right.

    I'll drop some impressions over in the 3WC-15 thread, but the Studio B did not disappoint. We were using the 4-Ohm taps fyi.

    I'm going to try this at home with my Klipschs. I've got an Aegir on hand which is maybe not the correct choice for bass duties in a biamp setup, but at 5x the power of the ECSB, it can't hurt!
     
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  15. Marvey

    Marvey Super Friend

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    Definitely dial in things by ear!

    1.5db steps! Not good enough. I dial in bass to 0.1db increments - just kidding. Actually to 0.25db on my DCX2496 over the course of several weeks listening to a lot of music. It's easy for me to get incredibly anal retentive about these things - but then again this is what speaker building can do to you!
     
  16. Curado

    Curado Rando

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    I think it is possible, but you'll have to look into the output circuit.

    Follow the wires from the output transformers, headphone jacks, and the SE/XLR switch, and see if it's possible to desolder some connections so that output signal can be directed to only one of them.
     
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  17. Marvey

    Marvey Super Friend

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    May want to ask Craig why BAL output is still on while the switch is to SE mode. I am pretty sure there is a funky reason for this.
     
  18. CharlesM

    CharlesM Rando

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    Hi all,
    new Frenchie here - I placed an order on a Studio B a few days ago. It seems they have very (very) few amps still available.

    Anyway thanks all for the different feedbacks and measurements - been a lurker for quite a long time here before signing up.
     
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  19. poohlikehoney

    poohlikehoney Rando

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    Arrived a few days ago and here are some day 1 initial impressions of this amp. Running it with a pair hd800(SDR) and verite. Using JJ tubes and stock driver/rectifier tubes.

    Day 1
    - The staging is huge for a headphone amp. Probably the widest or least compressed I've heard from these headphones.
    - Everything is well spaced incredibly expansive and well separated. This is very noticeable with both headphones used. Never heard anything of this nature before.
    - Incredibly nuanced especially in the lower frequencies. Seems some notes seems easier to notice.
    - Slams pretty hard. Digs deep into the lower freq. Love the way it hits when the bass drop. Hits hard and also remains nuanced.
    - There's a certain lushness not found in other amps I've tried over the years. Incredibly smooth and not overly done in anyway. Not sure if this is due to the 300b tube nature of the design of the amp.
    - Both the hd800 and verite tend to have a bit of etch in it's lower treble range but none of it is found. Probably my favorite amp so far with the hd800.
    - Find the overall tone pretty neutral-ish. Not overly warm and certainly not harsh sounding. There is definitely a underlying smoothness presented especially in it's mid-bass. Will need more time to process.

    Will be posting some comparisons with the Starlett in the coming days. So far the experience has been very positive.
     
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    Last edited: Jul 16, 2021
  20. poohlikehoney

    poohlikehoney Rando

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    A small note on it's tonality. After spending a bit more time listening it's definitely not a neutral sounding amp. It's tilted slightly towards a warmer tone. Not sure if this was due to the JJ tubes.

    In terms of headphone pairing, the hd800 absolutely sings with this tonality. Guitars has have a sufficient bite and weight. It is difficult to get hd800 to sound right on any setup really but this amp really is as close to ideal for my taste as it gets with the hd800.

    The verite on the other hand is a bit more complicated. On first listening it impresses with it's massive staging and and slam. The lushness in its mids-bass is very addictive to listen. But guitars does seem to lack bite and cymbal crashes is a tad muted. It plays more towards verite's strengths rather than patching it's one glaring trait which is a slightly sucked in upper midrange. A post by @ChaChaRealSmooth best sums this up.
    The studio b epitomizes enhancing the zmfness. I find it very enjoyable but suspects better synergy to be found elsewhere for my taste. Will be interested to hear it with eml tubes which are supposed to be more solid state sounding and less 300b so to speak. Will be looking to roll some other tubes in the coming weeks/months so any recommendation will be much appreciated. Tubes that tilt it slightly towards a neutral sound will be ideal. The Linlai e-300b seems pretty good but that's going into the kilobuck range.
     
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