Oh Sh#7! Eddie Current Studio B

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

  1. Rthomas

    Rthomas Friend

    Friend
    Joined:
    Sep 28, 2015
    Likes Received:
    942
    Trophy Points:
    93
    Those are the best photos of an EC amp I have seen. Just beautiful and better than what Craig uses on his website :D

    Congrats on the purchase!
     
  2. Boops

    Boops Friend

    Friend
    Joined:
    Nov 8, 2015
    Likes Received:
    2,753
    Trophy Points:
    93
    Location:
    New York
    I've been able to keep the power supply closer to the amp than I would have expected based on my previous experience with AF. Does the fact that the output transformers are inside the case in the Studio B make them less susceptible to coupling/hum from the power supply transformer?
     
  3. Hands

    Hands Overzealous Auto Flusher - Measurbator

    Staff Member Friend MZR
    Joined:
    Sep 27, 2015
    Likes Received:
    12,243
    Trophy Points:
    113
    Location:
    Colorado
    Home Page:
    I would not be surprised if the chassis offers some amount of shielding that helps with these sorts of problems.
     
  4. purr1n

    purr1n Desire for betterer is endless.

    Staff Member Friend BWC
    Joined:
    Sep 24, 2015
    Likes Received:
    83,452
    Trophy Points:
    113
    Location:
    Padre Island CC TX
    It does.
     
  5. Ninja Pirate

    Ninja Pirate Friend

    Friend
    Joined:
    Sep 28, 2015
    Likes Received:
    162
    Trophy Points:
    43
    Location:
    NH
    Home Page:
    So I got a new space heater in for the desk at home...

    [​IMG]

    Wow, this thing is massive. I think its officially bigger than my PC.

    Haven't had too much time with it yet but some initial thoughts and comparisons vs Mogwai SE (new to me, V1 with added 8ohm tap for HPs):

    Using PC --> TT2 (via usb) --> amps
    • Noise floor is pitch black once tubes are warm. A very nice change from the Mogwai SE (apparently noise floor was addressed in V2 but my V1 Mog is noisy unless I'm using 12au7/6384 combo)
    • With the stock tube complement and Gold Lion 300b's, the Studio sounds less gooey/thick vs the Mog SE...
    • The sense of spaciousness/air is much greater on the Studio. Having never tried anything else from EC or A&S at length, I'm not sure if what I'm hearing is more to do with the overall amplifier topology/design vs tube selection vs me being baked, but whatever, it's what I'm hearing.
    • No reduction in bass impact vs Mogwai (8/32 ohm taps, 300 ohm tap makes a lot of things sound flabby).
    • The cheapo Gold Lion tubes I have are very microphonic... I would love to upgrade these soon, just trying to figure out which set of 300b's are not going to break the bank...
    • With TT2 in fixed output mode, the Studio B needs about 1/4 of the volume knob to drive the VCs to a nice volume. A little less on the Utopias. Need to see how this does with some planars.
     
  6. batriq

    batriq Probably has made you smarter

    Friend
    Joined:
    Oct 31, 2015
    Likes Received:
    986
    Trophy Points:
    93
    I settled on the EML 300B. For the rectifier, consider using the Genalex GZ34.

    off-topic: that liquid container next to the amp is very stressful :)
     
  7. gaspasser

    gaspasser Flatulence Maestro

    Friend
    Joined:
    Jan 16, 2016
    Likes Received:
    5,756
    Trophy Points:
    113
    Location:
    Suburban DC
    29B5E7A9-5D4E-45F4-B06F-F8FE55117134.jpeg
     
    • Like Like x 11
    • Epic Epic x 1
    • List
  8. atomicbob

    atomicbob dScope Yoda

    Friend BWC MZR
    Joined:
    Sep 27, 2015
    Likes Received:
    17,090
    Trophy Points:
    113
    Location:
    On planet
    For those knowing internal details, how are the Studio B and Balancing Act 300B version similar and how do they differ?
     
  9. Ninja Pirate

    Ninja Pirate Friend

    Friend
    Joined:
    Sep 28, 2015
    Likes Received:
    162
    Trophy Points:
    43
    Location:
    NH
    Home Page:
    I... I don't know what you're talking about...

    Appreciate the recommendation for EML, will have to check those out. And I believe I already have a Genalex GZ34 kicking around from the Mogwai.

    Does anyone know if a 5u4 is compatible in place of the 5ar4?
     
  10. purr1n

    purr1n Desire for betterer is endless.

    Staff Member Friend BWC
    Joined:
    Sep 24, 2015
    Likes Received:
    83,452
    Trophy Points:
    113
    Location:
    Padre Island CC TX
    With respect to spaciousness, you may not have known this coming in, but the EC amps have high-frequency filament heaters. Filaments can be run DC or AC. Most AC heater implementations are off the wall AC, so they will run at 50Hz and 60Hz AC. There is a line of thought that AC heating for DHTs (2A3, 45, 300B, etc.) sounds more spacious than DC. This can work with speaker amps, but the problem is hum, which will be especially evident with headphone amplifiers. Craig got around the problem of hum by using a dedicated heater amplifier running between 45kHz-50kHz to drive the tube filaments.

    Another aspect of the spaciousness could be the use of a DHT (directly heated triode). The filament itself is the cathode which emits electrons (the small coils strings that light up red inside the plates) . Tubes like the KT88 are indirectly heated, where a filament heats a surround piece of metal that emits the electrons). The KT88s are also pentodes, but they can be run as triodes with much of the triode sound.

    There is a cult of folks including myself who love the sound of DHTs and would rather not have anything else. The downside is lack of power and poor efficiency - and vintage tubes which are getting harder to find.

    I think an interesting one for something different could be the EML 300B. I prefer the solid plate slightly over the mesh - more "solid" sounding - heh. Slightly microphonic DHTs are not necessarily a bad thing. It's been speculated that part of the spaciousness or richness of these kinds of tubes could be the directly driven filaments vibrating at a very small level. It could also have to do with the glass structure and internal plates which fit into the glass structure, which may affect the electron cloud inside the glass. The KR PX-4 of the OG BA (predecessor to this amp), was very microphonic tube. I suspect this was one of the reasons why the KR tube sounded so good, so rich. FWIW, I do not recommend the KR tubes. They are difficult to obtain, and quality and service are shit - at least from a North American perspective. KR as a company turned to shit when Kron died and left the business to his wife.

    I believe it should work. However, the tubes are different. The 5AR4 / GZ34 was chosen for its stiffness or lack of voltage drop. The voltage from the 5U4 rectifier will sag. As a result, the amp may sound different - maybe softer.
     
    Last edited: Feb 2, 2021
  11. purr1n

    purr1n Desire for betterer is endless.

    Staff Member Friend BWC
    Joined:
    Sep 24, 2015
    Likes Received:
    83,452
    Trophy Points:
    113
    Location:
    Padre Island CC TX
    Some info here if you missed it: https://www.superbestaudiofriends.o...ddie-current-studio-b.9761/page-2#post-322581


    OG Balancing Act -vs- Studio B (some are educated guess or estimates)

    Different output transformers
    • ElectraPrint OPTs 5k to 16 -vs- Custom 3.5k? to 4/8 with tertiary winding
    • No feedback -vs- feedback (< 2db) via tertiary winding
    • KR PX4 / 300B -vs- 300B only
    • Studio B is more optimized for 300B operation and will power efficient speakers down to 4-ohms
    • OG BA was headout and balanced lineout only. (the phono was passthru)
    Different PS
    • Small preamp rectifiers -vs- 5AR4
    • 250V -vs- 300V plate
    • Filament voltage adjust (between 0V and 5V) with sexy meter -vs- none (obviously)
    • No choke PS -vs- with choke: CLC
    • Big PCB for high-frequency heater inside the PS -vs- small chip amp heater board and oscillator inside amp chassis
    • x2 donuts power transformer (B+ and filament) -vs- x1 EI with two secondary windings
    • Slightly more power for Studio B
    Other stuff
    • 6SN7 -vs- WE396a
    • Line out (XLR) -vs- speaker (Speakon) outputs
    • Headphone amp less gain -vs- efficient speaker amp with more gain
    • Cinemag CLMI15 transformers for XLR input -vs- SE input only.
     
    Last edited: Feb 10, 2021
  12. Ninja Pirate

    Ninja Pirate Friend

    Friend
    Joined:
    Sep 28, 2015
    Likes Received:
    162
    Trophy Points:
    43
    Location:
    NH
    Home Page:
    Thanks for the detailed response Marv! Reading this once again reinforces how little I know on the subject... Time to go do some research.
     
  13. atomicbob

    atomicbob dScope Yoda

    Friend BWC MZR
    Joined:
    Sep 27, 2015
    Likes Received:
    17,090
    Trophy Points:
    113
    Location:
    On planet
    Thank-you, I did miss this due to skimming and thinking you were addressing a different issue. When I receive my unit I will put it through my standard measurement suite.

    By now anyone paying attention knows my reason for measurements is primarily component characterization, not better / worse comparison. Comments that I find off-putting include "Amp A mops the floor with amp B." I've come to appreciate how personal preference influences perceptions. Individual perceptions do not necessarily extrapolate well to others. Learning to triangulate through reports is a helpful skill to develop.
     
  14. Boops

    Boops Friend

    Friend
    Joined:
    Nov 8, 2015
    Likes Received:
    2,753
    Trophy Points:
    93
    Location:
    New York
    Noticing you have the amp chassis right up next to the power supply. Do you get any humming/buzzing keeping the power supply that close? I've been able to keep mine semi-close but I never tried having them right next to eachother. (Other EC amps with exposed transformers tend to need much more distance)
     
  15. Ninja Pirate

    Ninja Pirate Friend

    Friend
    Joined:
    Sep 28, 2015
    Likes Received:
    162
    Trophy Points:
    43
    Location:
    NH
    Home Page:
    I haven't noticed any hum coming from either unit (other than at power on), and its not noticeable thru headphones. This is with a maybe 1/2" gap between them.
     
  16. bobmysterious

    bobmysterious Facebook Friend

    Joined:
    Feb 14, 2016
    Likes Received:
    65
    Trophy Points:
    43
    Location:
    Boca Raton, FL
    Hi y’all, got a question for the group. I’m beginning the ordering process for a Studio B and contacted Mr. Craig to ask a question or two. Just on the off chance I asked if there were any secret menu options (there weren’t) but he said that some people prefer different coupling caps and volume pots in their builds. So my question to y'all would be don’t mess with perfection, or play around with it - and if so, what caps and pot would y’all recommend?
     
  17. m17xr2b

    m17xr2b Friend

    Friend Banned
    Joined:
    Mar 26, 2016
    Likes Received:
    3,980
    Trophy Points:
    93
    Location:
    United kingdomland of fish and chips
    Get the amp as the manufacturer built it, don't try to be smarter than the man who designed it. The options of upgrading are reserved for the DIY knowledgeable types who know what they're after and what to change while accepting the risk of doing so. Asking for custom stuff may just piss off the builder. For my very personal preferences, I'd want Duelund CuSn coupling caps and TKD 2P65CS pot but that's at least 1K extra.
     
    Last edited: Feb 6, 2021
  18. bobmysterious

    bobmysterious Facebook Friend

    Joined:
    Feb 14, 2016
    Likes Received:
    65
    Trophy Points:
    43
    Location:
    Boca Raton, FL
    Thanks for the advice, I’ll go with the unit as is.
     
  19. totlsota

    totlsota Rando

    Joined:
    Sep 1, 2019
    Likes Received:
    30
    Trophy Points:
    13
    Location:
    London, United Kingdom
    Decisions. I've admired both makers for some time. So now:

    Get in on the probably last Eddie Current with this Studio B (on a somewhat shorter queue)
    or
    Get in the (longer) queue for a DNA Stratus? (I don't think I'll let myself go Stellaris yet)
    I'm using ZMF Verite Closed.

    I've got a Glenn OTL and more recently added a 1101 Audio Blue Halo (I have 2 listening locations). I'm looking to get a transformer coupled amp - something different - which could power efficient speakers (unlike the OTLs).

    Any thoughts from you informed people?
     
    Last edited: Feb 7, 2021
  20. CEE TEE

    CEE TEE MOT: NITSCH

    Friend IEMW
    Joined:
    Sep 25, 2015
    Likes Received:
    3,036
    Trophy Points:
    93
    Location:
    California Bay Area (San Francisco)
    Home Page:
    ^Studio B now, Stellaris later!
     

Share This Page