Massdrop x Eddie Current ZDT Jr. (Official Thread)

These tubes are complete analogues.

6N24P in another pinout is called 6N23P (ECC88)

if I put near 6N24P and 6N23P you will not find any difference between them.

In fact, this amplifier works well-known 6N23P (ECC88), but with a different Pinout.

6N24P (ECC89) and 6N23P(ECC88) without changing the PCB pattern can not be changed.

6N24P is a redesigned 6N23P to work in circuits where one triode works on the second.

 

So to be clear. The 6N24P (ECC89) can be used as a direct replacement in this amp. Thanks.

 

You can still try 6N14P, ECC84, 6CW7, 6L16
The amplifier will definitely sound different.
You will like this sound or not-it will be your personal preference.
All of these tubes one group, although are not exact analogs, as ECC89
6H14P is the parent 6H24P

Detailed specifications can be found here https://www.radiomuseum.org/tubes/tube_ecc84.html

 

Any update about fixed version for RMA?

 

From Massdrop:
Hello Everybody,
We have an update on your Massdrop Made product. The Massdrop x Eddie Current ZDT Jr. is nearing completion and we expect to begin shipping in mid-April 2019.
If you have any questions, please feel free to reach out. We look forward to you receiving and enjoying your Massdrop x Eddie Current ZDT Jr. soon. Thank you for your patience.

a little behind their original estimated ship date of Feb...

 

Coming from Russia I'd be happy it's coming at all LOL

 

Having fixed the hum issue a while back, I enjoy my ZDT Jr. very much. Really good amp, at a really good price. Swap out the stock tubes with those listed earlier. (I am using the ECC 89 with no problems, but try them at your own risk) and the amp is very engaging. Worth the wait IMHO.

 

Thanks to all for the info posted on the ZDT Jr. I recently bought the amp up for sale from DEATHxMACHINE who I believe acquired it from brencho. The amp has GE 5654W JAN tubes and I believe the original Russian 6N24P tubes (the lettering on them is not very clear).

I don't have much experience with tubes (I have a Bottlehead Crack + Speedball). But I am very surprised by how long it took for the amp to "settle down" (source Emotiva erc1 CD player, to amp, to HD650). The first evening it sounded very weird and "confused" (almost like when a sub woofer, or an iem is out of phase). The next evening the weirdness had gone, but the bass was really sloppy and the treble (urgh, cymbals were just harsh noise). Third night it started to sound OKish but not engaging. 4th night it sounded nice (I wonder whether it will continue to change).

Much of what I'm hearing has been mentioned by others who are more eloquent, so not sure if this contributes much (also apologies for my inadequate descriptions).
Now my ZDT Jr. has been on for 4 days, the bass is not very taut/fast and cymbals are still a little harsh (they do not shimmer). Also the soundstage is very close (singers seem to be 3-4 ft away).

However the soundstage is not flat (like the jotunheim) and the instruments are nicely separated from each other despite sounding very close. Its very easy to pick up details, so small noises from vocalists (breath intakes, etc) are very apparent. Its got great tone for double bass and bass guitars. As others have said, the mids are portrayed really nicely with this amp. Overall its a very enjoyable amp for me with the HD650s (listening to blues, acoustic instruments, vocals, etc).

I thought the MCTH was a nice (and affordable) sounding amp with the HD650, but the the ZDT Jr. is smoother (less grain) and has more "texture", a nicer tone, and is distinctly more enjoyable/engaging with the HD650s. Also the ZDT Jr. sounds pretty OK with the He560.

The ZDT Jr. is a really cool-looking piece of gear (this was important to me during the first couple of days when frankly it sounded pretty nasty).

I know that some folks leave their tube amps on all the time. For folks that turn their's off, how long does it take for the ZDT Jr. to re-stabilize and sound good again? Also - stupid question but - how safe is it to leave tube amps on all the time (will it burn down the house?). Thanks!!
(Edited typos)

 

You are correct, I purchased it from brencho.

 

Thanks for your advice purr1n !!
30 min to 1h warm-up is generally enough for my Bottlehead Crack amp. I was worried that the ZDT Jr would somehow be different and take a particulary long time, since it has taken so long to stabilize.
(I'm relieved that the ZDT Jr. won't take 4 days to warm up from being off.)

 

Apologies, I don't want to bore you folks with a blow-by-blow account of my ZDT Jr. stabilizing. But, a couple of additional things I'm noticing with the ZDT Jr. As the amp stabilized the perceived position of instruments changed. So on day 3 or 4 listening to Keb Mo (song linked below) it sounded like I was sitting at his feet (his voice was positioned above, although guitars were at normal height). Now the amp has been on 5 days contiunously, Keb sounds like he is singing directly in front of me (a more normal position).

Also the cymbals (drum high-hats) are now less harsh (which is an improvement), however they are not well resolved (sounds like someone's telling you to be quiet by "shusss", instead of a more detailed/textured shimmer). I also get a sense that the bass has improved. The soundstage with HD650 is still very close (I can imagine that some folks may not like this). However the tone on this amp is lovely!!

I also tried the Beyerdymanic T1s - I don't listen to these often, they have a troublesome treble for me. With Keb Mo's tune (below) which has a lot of cymbals the T1 and ZDT Jr were a poor match (but I'm pretty sensitive to treble). However this pairing with Hugh Laurie's "St James Infirmary" was really wonderful, actually really special (Link below)

This is a well recorded CD and has lots of very funky-fun mid range instruments (although it is weird having House singing to you). The piano, sax and double bass sounded really awesome and the double bass had all that wonderful texture due to vibrating strings and also great tone. I'm not sure if the sound of the piano was "accurate" (pianos sound so different to me in different venues) however the piano notes were "round" and full with that great inital fast and then slower decay sound. And the wider soundstage of the T1 vs the HD650 with the ZDT Jr. was also very nice.

For me this amp certainly has limitations (mainly close soundstage; and it's prob not great with a wide range of headphones; and I'm thinking that its strength are in genres like acoustic, vocals and blues). However it was really awesome with T1s (and HD650s) and Hugh Laurie.
[Note - thanks for your patience and there will be no more ZDT Jr. warm-up posts from me, since I turned the amp off last night .]

 

Got a use one. Sound fantastic, but it also have humming issue. I am thinking if I can directly move the transformer out and put it in a separate box. However, idea size of project box is not easy to find, especially one with a IEC socket knocked out. Maybe I should try @AudioFriend's method because it seems to be the most economic method. @AudioFriend have you every try simply relocate the main transformer without any shield?

 

My “fixed” or v2 version arrived this week. Presently buzzing like an industrial apiary, left-channel through cans and whole unit from several feet away but will play with positioning and try some More robustly-shielded cables to investigate further.

Anyone else have a revised unit set up?

 

Fortunately, my fixed ZDT Jr. appears to be running fine so far.

BTW, just a brief impression of the fixed unit with stock tubes that I noticed immediately...
I'm not sure if its due to the hum being gone, but the fixed unit does sound a bit different. Mainly, the instrument/voice positioning has changed to something that sounds like it's being played right in front of you in a very tangible way. Perhaps it was like this to a certain degree before, but it's really noticeable now. I'm assuming this is what Hikergrl was referring to above when mentioning stage/imaging. There's this 3D/holographic effect, but with a easily noticeable/definable small sound stage that's right in front of you.

 

This problem is familiar to me. There is probably an offset in your DC power supply. With DC bias, toroidal transformers are very capricious. The transformer heats up, hums, and is the source of the interference.
If you have the opportunity and desire - it can be easily checked.
Need 30 to 100 kOhm resistor, the capacitor 4 to 10 uF (you can use the starting capacitors from the electric motor) and a multimeter capable of measuring DC milivolt.

Going scheme



The appearance of the installation




In my case, the average DC voltage offset of 24 mV

But this only day. I don't listen to music with headphones during the day. In the evening, the displacement falls to almost zero and does not interfere with me.

This problem sometimes occurs with us and the fans made special filters protect against DC offset.
For example such

 

You have good hearing and you hear microsounds. Microsounds in music are like spices in good food. Spices quite a bit, but they radically change the taste and impression of food.

PS. I knew a unique person, a woman. She was radio operator. This woman was capable of receiving Morse code when I heard only the noise of the ether.

 

I also got a fixed unit today, and after I forgot it running for about 10 hours straight while I was at work today it sounds pretty clean in terms noise. The first and second unit I got had a very noticeable hum in the left channel when the music stopped, but this one is significantly quieter. I believe don't believe the second unit was a 'fixed' one, since it was a replacement from before the email offering to fix affected units.

The new unit definitely feels like it has a different soundstage from the first ones I got. Some things seem to image slightly differently, noticeably things seeming to be above my eyes instead of in line or slightly below. Noticing this change is what prompted me to check this thread again. Definitely a fun amp!