Massdrop x Eddie Current ZDT Jr. (Official Thread)

Discussion in 'Headphone Amplifiers and Combo (DAC/Amp) Units' started by Hands, Nov 15, 2017.

  1. purr1n

    purr1n Finding his inner redneck

    Staff Member Friend BWC
    Joined:
    Sep 24, 2015
    Likes Received:
    48,300
    Dislikes Received:
    78
    Trophy Points:
    113
    Location:
    Antarctica
    Could be tubes. I've found that on occasion, some old tubes will pop or crackle. Sometimes pretty loud. This usually happens most frequently in the first 48 hours, then subsides. I figure maybe impurities inside the vacuum that need to burn off. HD600 drivers can hit mechanical excursion limits fairly easily.
     
    Sqveak and Zampotech like this.
  2. gixxerwimp

    gixxerwimp Professional tricycle rider

    Friend
    Joined:
    Sep 30, 2015
    Likes Received:
    2,054
    Dislikes Received:
    13
    Trophy Points:
    113
    Location:
    small island claimed by China
    So using the basic equation P=V^2/R, does this mean that the output transformer limits the max power output to 120mW @300Ω?
     
    Zampotech likes this.
  3. Zampotech

    Zampotech Friend

    Friend
    Joined:
    Oct 15, 2018
    Likes Received:
    882
    Dislikes Received:
    0
    Trophy Points:
    93
    Location:
    Moskou
    Yes, you have calculated it.
    Unfortunately I don't know PMPO headphone SenHD600
    Power for "loud" status for these headphones is about 12-15 mW

    I find it hard to discuss SenHD600, I have only SenHD580, but my other headphones Beyr DT770 are unable to destroy 12v/50hz. (570mW) This experiment on the survival of the headphone was carried out accidentally, as a result of my error in switching.
     
    Last edited: Jul 29, 2019
    gixxerwimp likes this.
  4. atomicbob

    atomicbob dScope Yoda

    Friend BWC MZR
    Joined:
    Sep 27, 2015
    Likes Received:
    9,364
    Dislikes Received:
    3
    Trophy Points:
    113
    Location:
    On planet
    sensitivity for a number of common headphones may be found here .
     
    bluebyte60 and Zampotech like this.
  5. Zampotech

    Zampotech Friend

    Friend
    Joined:
    Oct 15, 2018
    Likes Received:
    882
    Dislikes Received:
    0
    Trophy Points:
    93
    Location:
    Moskou
    Impressive research. Many figures were unknown to me.I will use your results. Thanks so much
     
  6. Zampotech

    Zampotech Friend

    Friend
    Joined:
    Oct 15, 2018
    Likes Received:
    882
    Dislikes Received:
    0
    Trophy Points:
    93
    Location:
    Moskou
    Dear friends.
    Today I sent the last roll out of this box.

    If anyone else needs steel transformer tape, let me know. In this case, I will buy such cores, It will add $4 to the shipping cost and slightly increase the preparation time.

    I publish another modding that increases the width of the scene in NBM. I installed this protection in my NBM

    Probably this protection reduces noise/hum, but in my NBM there is no noise, and I have nothing to compare

    [​IMG]
     
    Last edited: Jul 30, 2019
    hikergrl and gixxerwimp like this.
  7. gixxerwimp

    gixxerwimp Professional tricycle rider

    Friend
    Joined:
    Sep 30, 2015
    Likes Received:
    2,054
    Dislikes Received:
    13
    Trophy Points:
    113
    Location:
    small island claimed by China
    Any other improvements you can hear besides increased width in the sound stage?
     
  8. Zampotech

    Zampotech Friend

    Friend
    Joined:
    Oct 15, 2018
    Likes Received:
    882
    Dislikes Received:
    0
    Trophy Points:
    93
    Location:
    Moskou
    I didn't notice any other changes.
     
  9. peoplee

    peoplee Rando

    Joined:
    Apr 30, 2017
    Likes Received:
    2
    Dislikes Received:
    0
    Trophy Points:
    3
    Location:
    Asia pacific
    Just received this wonderful amp for a week, the imaging/ depth of each instruments is natural & realistic. However, has anyone experienced channel imbalance(right channel is about 2 dB louder)? It not just happens bellow 9 o’clock but all the way except maximum. And around 2 o’clock the potentiometer becomes es difficult to turn and the right channel becomes no sound. Gee, what should I do?
     
  10. Lyander

    Lyander Too sensitive for SBAF

    Friend
    Joined:
    Feb 25, 2017
    Likes Received:
    4,019
    Dislikes Received:
    23
    Trophy Points:
    113
    Location:
    Pasig, Philippines
    What steps have you taken so far to troubleshoot? Swapped tubes around, checked that interconnects were secure and that no DSP was in effect? It could be hearing or headphones— have you measured 2dB imbalance, or tested imaging with a pure tone in mono? Is this imbalance manifest on other amps?

    Not calling your competence into question, just that people can overlook simple things often. I do it a lot, and just recently one of my best friends thought she'd lost one of her favourite fountain pens. Turned out it was in her pants pocket, which wasn't typical of her but still somewhere that warranted checking.
     
  11. yotacowboy

    yotacowboy McRibs Kind of Guy

    Friend
    Joined:
    Feb 23, 2016
    Likes Received:
    1,655
    Dislikes Received:
    10
    Trophy Points:
    93
    Location:
    NOVA
    Home Page:
    mailto:[email protected]
     
  12. Ksaurav402

    Ksaurav402 Acquaintance

    Contributor
    Joined:
    May 7, 2019
    Likes Received:
    80
    Dislikes Received:
    3
    Trophy Points:
    18
    Location:
    NY
    I did have imbalance at higher volume ever so slightly but I replaced stock tubewith JAN GE5654w after may be 1 day of use and after proper burn in I don't hear any imbalance except at very low volume which is kind of expected. Swap the tube around and let them burn in for 2 days. This issue may go away.
     
  13. Ringingears

    Ringingears Honorary BFF

    Friend
    Joined:
    Sep 26, 2015
    Likes Received:
    3,413
    Dislikes Received:
    3
    Trophy Points:
    113
    Location:
    Northern Californium Valley
    ^^Do that. It should not be doing that. Sounds like a potentiometer. Mine is smooth to operate at any position on the clock.
     
  14. yotacowboy

    yotacowboy McRibs Kind of Guy

    Friend
    Joined:
    Feb 23, 2016
    Likes Received:
    1,655
    Dislikes Received:
    10
    Trophy Points:
    93
    Location:
    NOVA
    Home Page:
    This sounds like the volume knob is binding on either the casework/face plate, or there's something mechanically wrong with the pot.
     
    Lyander and Ringingears like this.
  15. Ringingears

    Ringingears Honorary BFF

    Friend
    Joined:
    Sep 26, 2015
    Likes Received:
    3,413
    Dislikes Received:
    3
    Trophy Points:
    113
    Location:
    Northern Californium Valley
    Or both. Either way if it’s under warranty, I would return it. Somethings wrong and it should be fixed if under warranty.

    Sorry, usually not so blunt, but Drop is a good company and will make it right. IMHO, etc.

    Edit: Sorry to hear you are having problems with your amp. When it’s finally working right I think you will be very pleased.
     
    Last edited: Aug 2, 2019
    Lyander likes this.
  16. peoplee

    peoplee Rando

    Joined:
    Apr 30, 2017
    Likes Received:
    2
    Dislikes Received:
    0
    Trophy Points:
    3
    Location:
    Asia pacific
    Yep, I’ve tried not to be foolish before posting a thread.
    My Eddie was connected to m9xx, capable of adjusting channel balance up to 6 dB , as dac/preamp, and that’s why I figured out around 2 dB. And when I connect to m9xx no imbalance noted what so ever.
    Thanks for your feedback.
     
    Lyander likes this.
  17. peoplee

    peoplee Rando

    Joined:
    Apr 30, 2017
    Likes Received:
    2
    Dislikes Received:
    0
    Trophy Points:
    3
    Location:
    Asia pacific
    Hmm, thank you for your info, it seems to be a faulty potentiometer.
     
    Ringingears likes this.
  18. fp627

    fp627 Friend

    Friend
    Joined:
    Sep 26, 2018
    Likes Received:
    336
    Dislikes Received:
    7
    Trophy Points:
    63
    Location:
    SouthernCA
    After a few weeks with JAN GE 5654 tubes, I don't really think the tubes are an upgrade. They just provide a different tone, sound, and voice. And while my "complaints" are somewhat reduced, this amp has lost it's own special sound and tone in the process. Can't find it now, but earlier in the thread someone said this amp was very specifically voiced for Russian tubes. I COMPLETELY agree. Luckily GE5654 tubes were not expensive and not hard to obtain.

    For anyone who wants to tube roll, I'm going recommend trying to find Russian tubes other than the stock Voskhods in addition to GE 5654. Overall, I do agree that one could get the GE 5654 and call it a day (and just switch between these and stock tubes as needed).

    With the GE5654, I also prefer the low Z jack most of the time regardless of actual Z value of my headphones. It seems slightly bloomy and bloated at times, some decay isn't fast enough (both uncharacteristic for EC house sound from my experience) but overall it just seems a little more musical. This is true with different DACs and headphones. Will have to go back to Voskhods again or possibly new tubes and see what I prefer there.
     
    Last edited: Aug 3, 2019
    hikergrl, peoplee, Dzerh and 3 others like this.
  19. PrismaticOrb

    PrismaticOrb Rando

    Joined:
    Jul 21, 2019
    Likes Received:
    5
    Dislikes Received:
    1
    Trophy Points:
    3
    Location:
    F
    The replacement is as quiet as its going to get. The volume pot knocks back and forth when turning it up or down though and is a bit rough turning, but sounds clean though. No other issues with this one besides the volume pot which does not effect its performance.
     
    Zampotech likes this.
  20. gixxerwimp

    gixxerwimp Professional tricycle rider

    Friend
    Joined:
    Sep 30, 2015
    Likes Received:
    2,054
    Dislikes Received:
    13
    Trophy Points:
    113
    Location:
    small island claimed by China
    I'm still holding off on posting full impressions of my de facto ZDT Jr (it's a NBM), but here are some comments.
    Other than filling out and tightening up the bass a bit and being a touch more forward, I agree that the GE isn't an upgrade in overall sound quality. Depending on the source material, I probably wouldn't notice the difference.
    Would appreciate it if anyone has any specific recommendations. I'm not up for random purchases from the former Soviet bloc. Every time a package shows up at our door, my wife asks, "What did you order now???!!!"
    For me, HD650M has tighter bass on high-Z out and bloated mid-bass on low-Z out. With Clears it's the opposite. With each phone out of preferred output (Senn = high, Focal = low), the overall sound is wetter with more extended decay than MCTH (but not overly so). Soundstage is wider, and while I can't say for sure that imaging is tighter, the presentation of how instruments and vocals are placed seems more "alive" (sorry, don't really know how to describe it). If not for the poor bass extension and slight flabbiness in what's there down low, this would (could?) replace MCTH for me.
     

Share This Page