Massdrop x Eddie Current ZDT Jr. (Official Thread)

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

  1. Meh

    Meh Friend

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    I may be experiencing a similar problem as your not enough current problem ( I have no problem with Hum, however)

    I experienced this problem with the ZDT Jr I ordered from the latest drop:

    It worked fine for the first few days and sounded great, then I noticed that the R channel was fading completely out at times for a few seconds and then fading back in. This was using the High Z out. It didn't happen with the Low Z out.

    I tried different cables and tubes and different DAC's ( EL DAC and Airist R2R) but the problem kept reoccurring with both my headphones - 6xx and Elegia.

    Drop was great about allowing a return and I'm now awaiting a replacement.
     
  2. fp627

    fp627 Friend

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    Yes, I wiggled and reinserted tubes and have ordered new tubes already. Sounds like our solution is the same (this was my previously mentioned "action taken" although I deliberately omitted this).

    Will try this tonight. And I'll move to a different room, etc. But if this were the case, wouldn't the "no current sound" issue occur on both days? (rhetorical question only - I appreciate the idea and I'll do some more research to figure this out)
     
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  3. Zampotech

    Zampotech Friend

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    To @fp627

    I will follow your work with attention, and if I have enough brains and experience I will definitely help you.
     
  4. tommytakis

    tommytakis Friend

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    I purchased a used ZDT Jr. after reading through impressions on SBAF and was hoping it captured some of the magic of the ZDS that I used to own. Suffice to say, the ZDT Jr. did just that and definitely worthy of its title.

    The amplifier I purchased had the infamous humming issue, but I thought it would be a fun DIY project to try. Even with the humming issue, I loved the sound of the amp so I just said ‘F*** it’ and attempted the mods developed by the SBAF community. I’m a total noob when it comes to electronics and the only “experience” I had working with amplifier was building a Bottlehead Crack + SB. But thanks to the help of @Zampotech and @AudioFriend I managed to get the amplifier hum-free and I’m loving the sound even more.

    Chain used: Gungnir Multibit A2 Gen 5 > ZDT Jr. > HD650 | Verite | HD800

    My favorite headphone pairing with this amp was HD650. The ZDT Jr. had amazing clarity and microdynamics that help remove the Sennheiser veil and made it sound lively and dynamic. Like other members have previously stated, this amp really shines in the mids and treble. Any genre of music I threw at, it was detailed but never fatiguing or sharp. Instruments are well separated with adequate depth, despite lacking in width and the feeling of expansiveness with ZDS. Another reason why I love pairing with HD650 was that the headphone itself was never known for its bass extension, so the bass of this amp didn’t particularly bother me at all. This amp also resolves nicely with the 650, not quite at the level of ZDS but pretty close from what I recall.

    I also thought HD800 was another excellent combo from brief listening, but I just can’t stand the stock H800 sound, even with EQ. Maybe with the SDR + SBAF mod it might even be a better combo with this amp, amplifying the inherent qualities of HD800

    Pairing with ZMF Verite was another good combination, but I wasn’t floored/amazed like how I was with the HD650. My pair is still relatively new so I’m not sure if this is totally validated, but I liked pairing it with either universe suede or flat Verite pads since the amp helps reduce the treble edge a bit.

    Overall, I think this is an excellent amplifier for the price even with smallish stage and okay-bass for high impedance dynamic cans. I hope more people get to try this amp with their HD650 because despite owning the Verite, if I ever need to scale down for whatever reason, ZDT Jr+ HD650 would be my desert island combo.

    [​IMG]
     
  5. Justin S

    Justin S Rando

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    Longtime lurker here. I have been reading a number of reviews of the ZDT Jr. (including this thread) over the past year. When the most recent Drop happened, I put in an order right away.

    A bit of background: I'm a film pro and headphones have mostly been a working tool for me, not so much a "listening pleasure" device.

    Lately, I have been digging into headphones for the late night music (so i don't bug the family). I have worked my way through a small sample of amps and headphones: Magni 3, Burson Fun Vivid, the original Burson Soloist, the headphone output of the RME ADI-2.

    I tried the original HD650s, my old AKG 600ohm monitors, AKG Sextetts, my old (modded) Grado SR60s, ZMF Classics, and a custom grado build with the Magnum V8 drivers. All of them have had their charms, but I have always felt like headphone listening has been a compromise when compared to my monitor/speaker listening.

    I ordered the ZDT Jr., the GE driver tubes, and a used pair of 6xxs making my chain:

    W10 Roon>HQ Player (sometimes)>RME ADI-2>ZDT Jr.>HD 6xx/Magnum V8s

    I have experienced zero noise issues with the ZDTJ - it's dead silent when not being fed. I put 100+hrs on everything this week and am sitting down to listen as I type this.

    The first thing that strikes me about the ZDTJ is the detail. I am hearing so much more into mixes than I had been hearing using the previous listed amps. The second thing that really stands out to me is the sense of space. While the original Burson Soloist provided a pretty neat sense of space, the ZDTJ really opens this up - I'm hearing more space between the instruments and more spacial (room) cues.

    I should note that I'm using a small touch of cross-feed out of the ADI-2 when headphone listening. I'm listening to studio music right now: Made in Heights, The Books, T. Rex, James Blake, Wilco, Sparklehorse, Hendrix, Nick Cave...

    Other qualities that I think are notable about the ZDTJ with the GE driver tubes: when compared to my other amp experiences, the treble is very pleasant and not at all tiring (though there is a touch of grain I notice from time to time), I also find the bass really very satisfying - I know there have been many comments about it lacking bass, but I find it substantial, thrusty, tuneful, and clean. It's an exciting listen.

    In the scope of all your collective experience, I know that my noob sample size is small. I would say, though. that it is providing me with sound that has changed my headphone listening experience. ZDTJ with the 6xx is still not speakers, but it's not a compromise either - more like a destination. The ZDTJ works very well with my 6xxs and is also pretty great with my DIY grado/magnum build.

    I am curious about a how best to setup the gain between the ADI-2 and the ZDTJ. @atomicbob mentioned something about this in his measurements of the ZDTJ.

    "DAC is an ADI-2 Pro gain structured at -30 dBFS with ref set for +19dBu, and NOS filter. [...] When I post the ADI-2 Pro data it will become evident why I have chosen this particular gain structure."


    I have the ZDTJ set to about 1:30 which I understand is the 0dB mark for this amp and am adjusting the volume using the ADI-2 (which is set to auto ref level).

    When I listen to the hd6xxs with the ZDTJ, comfortable listening levels (using the RME volume control) are between -15.5 (first step when the rme swtiches to ref +1 dBu) and -21.5 (first step when the ADI-2 switches to ref -5 dBu).

    Am I getting the most out of things using this configuration?


    Edits: grammar and some clarifications

    One more edit: I just did a coarse emi test on my version of the ZDTJ by putting my phone on it and sending and receiving photos on both wifi and 4G. Data sent and received on my phone, not in the headphones. Whatever they did, this thing is more quiet than the rest of my gear.
     
    Last edited: Jul 12, 2019
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  6. fp627

    fp627 Friend

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    So the "no current sound" issue described above hasn't recurred since asking above. Have done literally nothing else other than reseat front driver tubes. No more hum either. Tried in multiple rooms and multiple outlets. Suspect it's one of 2 things:
    - BH crack is further away. Both used to sit next to each other about 1 foot apart horizontally but at different heights. The choke in my crack is also oriented in the same plane/direction as ZDT transformers. They now sit about 1.5 feet apart horizontally, same heights, and Ygg is now between them. However, even if I power both units on and put them touching right next to each other, I can't get ZDT Jr to hum anymore (and the crack never has and still won't hum).
    - Something weird with grounding in surge protector maybe ... I tried plugging and unplugging other audio gear, computer, etc, into same surge protector and no humming regardless of what is or isn't plugged in.

    Regarding my initial impressions of the sound:
    I'm not as familiar with EC house sound as others here but have heard Studio Jr (@ EC launch event), a few different AF, and a few other EC here and there. I have not heard original ZDT before. To me this has the EC house sound for the most part, about 60-80% depending on various aspects, the song, etc. A little leanness to the sound, aiming for clarity (over say fullness, wetness, warmth, etc), good amount of energy in the sound, a little bit of bite.

    Resolving enough that I can easily hear the differences between SDAC, 1421, and Ygg (IMO differentiating expected at $400, but easily is the keyword here). I like this amp best with 1421 except for loss of resolution, detail, etc. that comes with going away from Ygg and hence I still swap between the two. A 1541 would be nice with this (for me). Note that I felt Ygg was a great match for all other EC amps I've heard before. The up front in your face presentation of Ygg is a bit much for me with the extra energy in the mids of this amp on some songs. Oddly enough though, even when I forced myself to listen for 2+ hours, it didn't get fatiguing.

    So far a little too much energy in the mids and upper mids for me when using Clears. Contrary to what others are saying, I don't like this amp with HD6xx, will elaborate more later. I don't think this drives LCD3 or Ether Flow 1.1 well. Still waiting for new tubes to arrive and Auteurs will arrive soon too, will see if this changes anything.

    Compared to my modded BH crack and LP, I would say ZDT JR at about the same level as the modded BH Crack but with a very different sound. Also BH Crack is relegated to high Z dynamics, ZDT Jr has more flexibility. Still like the LP more than either of these overall (whether it be with stock EH or preferred Telefunkens) but there are still areas where ZDT Jr and Crack outperform LP.
     
    Last edited: Jul 14, 2019
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  7. Hands

    Hands Overzealous Auto Flusher - Measurbator

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    Those GE tubes in front add some bass and reduce the bite.
     
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  8. gixxerwimp

    gixxerwimp Professional tricycle rider

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    My initial impression after swapping the GEs into my NBM was that the bass improved a smidge, but they were more forward and bitey than the stock Voshkods. They've only had about 24hrs on them. Maybe they'll smoothen out a bit over time.
     
  9. Hands

    Hands Overzealous Auto Flusher - Measurbator

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    Hmm, interesting...More forward I could see. I wonder if we are using the term bite differently.
     
  10. fp627

    fp627 Friend

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    I use the term "bite" not as a positive or negative that I want more or less of, just a preference or sound signature thing. Two examples of what I think of: Recent HFM headphones where all models just sound too soft to some but relaxing to others. Solaris (loaner tour) where the lack of bite (along with other dynamics) make for a sound that's great for some and not others.

    Also, I use the term more subjectively / emotionally. My rough definition:
    Does the sound bite on to and engage the user? Or in other words, does it kind of "stick" and have a little bit of "ummmfff" where it gets in there? Or does it kind of sound like teflon where all the sound just comes in and rolls off? I do not define bite as dynamics, slam, harshness, a raised part of the freq response, or even say distortion that someone could intentionally introduce when playing electric guitar. Yes, a little dumb when written out on paper like this, but I've always found describing such subjective "feelings/moods/tones" to be a bit difficult for me - kind like how do you actually define feeling cold or hot? (if you really think about it and take away common shared experience of hot/cold weather/items)

    If I use the term incorrectly, please correct me.
     
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  11. yotacowboy

    yotacowboy McRibs Kind of Guy

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  12. futbutts

    futbutts Rando

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    I've been auditioning a few amps and had one of these come in, open-box from Blinq. I really dug the sound right away but detected a hum in the left channel almost immediately, so I boxed it up to return it. (MD doesn't honor warranties of their products sold on Blinq.)

    So I spent a few days with the LP and did my write-up of that. Someone on Head-Fi offered to ship me some tubes to roll, so I decided to spend some more time with the ZDT Jr. in the meantime. Lo and behold, the hum is not nearly as prominent as it was before; in fact it's barely audible, which was not the case before.

    As the tubes break in I appreciate the ZDT Jr more and more. Timbre is just so god-damn spot on, it's a very synergistic compliment to both the 600's and 800's. It's also a great match with the Ori's, which are fairly inefficient planars, so I was very surprised to find that to be the case. (The 650's are just a tad too dark-sounding with it to my ear, so far.) I've mostly only listened to tube amps at various shops and was always blown away by the good stuff, $1000+ ampsandsounds OTL amps and the like. I borrowed a friend's Bottlehead Crack for a bit and it was fun but maybe too much of a good thing with the tubey-ness. So to find a solid tube amp within my modest budget is both a relief and a welcome surprise.

    The ZDT Jr is also a very revealing amp, probably not to the extent of the LP, but I find the way ZDTJ presents those details much more to my liking than the LP's somewhat reserved attitude. It's much more engaging, the new details you pick up on feel much more complimentary to the song as a whole, whereas with the LP they somewhat just sound like mere embellishments. (Obviously, this is comparing a tube vs a tube hybrid, but it's all I have on hand to compare at the moment.) I adore the way the ZDTJ portrays lower mids, especially bass guitars, there is just so much texture and power behind the notes. (I never really appreciated John Paul Jones' bass playing before I heard his frantic bass guitar on 'Immigrant Song' through the ZDTJ, for example.) The bass response is good, not great. More modern, brighter recordings are much less enveloping in comparison to old recordings, which are really brought to life with the ZDTJ.

    I'll add that while I don't really understand the interplay between the low and the high impedance outputs, I've found I seem to prefer the low impedance one, even with 300 Ohm cans like the 600's or 800's. It seems more well-rounded, the bass response seems more prevalent which smooths out the overall sound very nicely. The high-impedance one seemed to sound more cacophonous, but maybe I didn't give it enough of a chance.

    I got a good deal on it, but there is that slight hum that irks the perfectionist in me (plus the chassis has a tendency to kind of bobble around on top of both my DAC and my desk, like a table on an uneven surface), so I am on the fence about either returning this and buying brand-new one from Drop or possibly just dealing with it. Is mitigating a tiny hum and having a warranty worth $80? Still thinking about it...
     
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  13. Zampotech

    Zampotech Friend

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    [QUOTE = "fp627, сообщение: 263902, участник: 6732"] и [/ QUOTE]

    I'll tell you how I eliminate the swing of different devices.

    I put the device on the edge of the table diagonally, on the protruding legs. And two hands a little press on the device on the other diagonal.
    Little effort and the device stands like a brick:)

    PS So I fixed a lot of DVD players and a few amplifiers. NBM was also

    EDIT This method works if the case is metal. Plastic cases eventually return to the curved position.
     
    Last edited: Jul 15, 2019
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  14. Hands

    Hands Overzealous Auto Flusher - Measurbator

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    Ah, interesting. "Bite" to me would probably mean oversharpened transients or a mid-to-upper treble peak that kind of gives too much glare and hardness.

    Think "bite" as in like the "bite" you feel when you step outside on an incredibly crisp, cold day.

    I think what you're describing is more a combination of transient response (fast? slow? sharp? soft?), dynamics (micro through macro), clarity and cleanliness, etc. And most I think would then sum up how "engaging" the amp sounds, which is a term you just used in combination with "bite."

    I don't necessarily know if this is the right or wrong way to use these terms for the broad population here, so I can't say one way or the other. :)
     
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  15. yotacowboy

    yotacowboy McRibs Kind of Guy

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    I think "engaging" or "involving" might be the better terms for what @fp627 is describing. Almost gets to the oft maligned "PRAT" thing.
     
  16. fp627

    fp627 Friend

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    Don't want to come across as argumentative, but again, not quite sure how I should describe it. This whole thing has turned into a good exercise with descriptive writing...
    I don't equate bite to engaging, musicality, involving, etc. those are still their own terms. Yes, I imagine anything with soft, smooth, and/or slow transients and lack of micro and macro won't have as much bite, but it isn't limited to being the opposite of this either. But that isn't quite it. I guess another example would be bite being like biting into a crispy panini with crispy ingredients within while no bite is like biting into really soft bread with just a little mayo and deli meat inside - neither is right or wrong, but you get a very different feeling going into each and some people will only eat one or the other, some people appreciate both... Anyways, hopefully I have kind of painted a picture of what I'm trying to say.

    but back to the amp now:

    On a different note could someone please PM me if you have a known source for matched 6N24P / 6FC7 / ECC89 aside from stock Voskhods? 15 min of searching including HF has yielded nothing. Seller for ECC89 I was buying just sent me a message stating that he made a mistake and they aren't close to matched. (5654 have already been ordered).
     
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  17. Hands

    Hands Overzealous Auto Flusher - Measurbator

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    Maybe you are thinking of the term "incisive"?

    Honestly I've had good luck just buying tube pairs on eBay without super close matching. Even easier when you get like a 4 pack NOS.
     
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  18. gixxerwimp

    gixxerwimp Professional tricycle rider

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    I was clumsy while swapping out tubes to test the spare set I got with my NBM and dropped one onto a tile floor (default in Asia) ... #smash #myavatar

    The spare set of stock 6N24P I had exhibited significant channel imbalance, even though they were supposed to be matched. Luckily I was able to match one of them by ear with the remaining original. No idea how far out the gain(?) would have to be to hear a significant swing in volume L to R.

    Oh, and by "more bitey" I meant increased upper mids and lower treble, so I guess the same thing as more forward.
     
  19. Orkney

    Orkney Acquaintance

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    You can search a while before finding a genuinely matched set. My "fixed" ZDT arrived with two blown tubes, including one of the 6Ns. Given the reasonable price of the stocks, your best bet may be to buy them in bulk (10 pc sets are common) and then use a tester or your ears to match. Generally IME vendors don't bother close-matching such modestly-priced tubes.

    I have a whack of these and can help out if you can't source a set that suits.

    I've been listening to me ZDT more than my old ZD recently -- runs cooler, easy to place in my office space, and sounds very good on most of my music from the Onyx I'm running it with. Still a bit hair-shirt, ad not the easiest to gain-match, but a still a ridiculous value if you get a good one.
     
  20. bluebyte60

    bluebyte60 Acquaintance

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    Finally got some free time slots to do the mod. @Zampotech kindly send me steel tape from Russia, I have use that to wrap the transformer.
    [​IMG]
    I did two tests. Before the cover is mounted, merely with the steel tape, the hum will still be audible. But after the cover is up, the hum is at a very very low level. It will take a lot of attention to notice that. Wish have more time to try the steps of @AudioFriend. It will take some efforts to remove to clean the glue and desoldering all those wires to remove transformer. It's a bit too far for me :D. At that level, I probably will move the transformer to another box. After the mod, I have been enjoy this amp for hours, it's very smooth with HD800 (stock version), sounds warm while holds the clarity. Still have some tapes remained, probably enough for 2~3 ZDT. Can shoot me a email, I can have that ship to you.
     
    Last edited: Jul 19, 2019

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