Massdrop x Eddie Current ZDT Jr. (Official Thread)

ok so on that image there, see right below the plug point on the black thing it says "use only with 250v fuse"... just realized it maybe telling me to use a 250v fuse INSIDE it.

 

+1 to what @Hands says. Fuses are providing protection from a high current. You should care just that the voltage rating of a replacement fuse is not lower, higher is fine.

 

Thanks guys,
Just saw that and was confused for a bit. Anyways, plugged it in (I have tonnes of spare power cords) and O.M.G LOVED IT instantly. It's not that I don't notice more subtle changes but I'm usually not so immediately reactive to changes unless it's super obvious. It wasn't like "nectar of the Gods" or "OMG I can hear things i've never heard before" or anything btw. But like how people say caviar is supposed to be awesome because it's fancy and expensive, but wouldn't you rather have that old familiar fave dish that your moms been making for you since you were a kid? That is to say, not good because of some objective thing, or some fancy tech but because it's good for ME, like it was tailored to my sensibilities to give me exactly what I like and want.

I've actually never owned a tube amp before, I'd barely heard one (maybe for a few minutes) at a store when I was testing out the some of the headphones there. But, a lot of people were saying the ZMF Atticus headphones I have go very well with tubes so I decided to take the plunge. Great price too! Now I'm just sad I won't be able to take this listening experience with me when I go out .

(Another sidebar question about this: a. how do I actually remove the tubes if I need to - pull or screw? And the back ones kinda tilt from side to side a whee bit...is that normal?)

 

Popping back in here with some lazy tube rolling updates: Mullard NOS 5654's seem to be another great option. A little rolled off at the tippy-top, but they still sound more spacious than the Sylvania JAN-5654s. Where the Sylvanias sound neutral in the upper midbass and mids, the Mullards are a bit wetter/more full sounding. There's a bit better "jump factor" in the power range of the frequency response. Kick drums and toms get a good dose of punch, better than the Sylvanias, and mid-90's grunge guitars on old Tool (as shitty as it's mixed), Jane's Addiction, and Alice in Chains are nice and crunchy. These seem to be great rock tubes. Listening to some avant electronic stuff now with no complaints. Hope that helps. Got mine off ebay for $40/matched pair.

I've read that the colloquialism "tube rolling" came from the description of the movement to remove a tube; rolling the tube around in small circles to loosen it from the socket. Could be complete bullshit, but whatever.

 

I have found that ecc89 tubes made the bass quite better, with more texture and definition.
Was wondering if this amp accepts ecc88 in rear tubes.
Maybe a dumb question, and I don’t want to detonate a bomb inside my little zdj

 

To enable ECC88 instead of ECC89 must be an adapter made according to this scheme




I tried to persuade a Chinese factory to make such an adapter, but I failed. Probably, if there is interest, I will make myself. A small jewelry factory is ready to make the brass pins for me.

 

I've said a lot of dumb things but not asked many dumb questions lately, so time to remedy that.

Installing shielding on the output transformer, but in order to take the enclosure off I believe I need to remove the PCB inside; in order to remove the PCB I have to somehow get under this misbegotten piece of uncooked pasta that leaves the last screw holding the PCB in inaccessible. Maybe I'm just really tired but I can't seem to figure out how to do that just yet. Trawled through the thread, apologies if I missed it.

Tried getting front plate off— unscrewed the hex screws on front panel to no effect. If this were my ZDT Jr I'd just clip off the excess and cook it (/s), but it's a loaner from a friend so I'll abstain from eviscerating the amp's innards.

 

It's very simple. You need to remove the nuts from the connectors






The front panel should not be removed

Photo from instructions on modernization.

What material will you use for shielding?

 

@Zampotech just saw your edit. I got some unidentified metal from @CEE TEE back when he was with Massdrop, I handed it off to the amp's owner thinking he'd install. He recently asked whether I could do it instead and offered to let me demo the amp while it's at my place.

Not sure what the material is. Also, I'm making it obvious that I don't mess around with electronics often, but what tool are you using to extract the nuts?

 

In appearance it is a Russian transformer tape type 3409. I have exactly the same. Excellent material for shielding.

Nuts are unscrewed by an end key on 11.

 

I had some JAN GE5654s and then some mystery tubes that say "6096TL / CV4010 KB/DC" at my parent's place that I decided to grab during thanksgiving.

I have to agree with @klyrish about the ZDT JR with the GE tubes and the 6XX. The DAC I used was the RME-ADI 2. The difference is immediately noticeable without even having to plug in the stock tubes for comparison. It really wakes up the 6XX and lifts away the veil while giving the bass a nice facelift by making it tighter. Really dramatic difference. I guess if you wanted a dedicated 6XX setup this would be it, I know this is kind of redundant to what was said earlier but just wanted to provide another data point.

The clear through that combination sounded fine but I would say mainly that the treble became a bit peaky and would stray into being a tad to harsh especially on electronic music/rap.

Sadly the mystery tubes which I don't remember how I got (I think they are mullards?) didn't work at all. They made everything sound thin and overall U shaped in a bad way on the 6XX. The bass was also kind of slower, bloaty, and unwieldly. Blink-182 just sounded wrong. And so did norah jones. Would not recommend unless that was something you wanted. I guess I could see it if you wanted like a maximum bloaty bass if you were listening to dubstep or something where the bass takes primacy over everything else.

I think I'll probably stick with the stock tubes because I do prefer them with the clears through the high Z output (I guess I'm a basshead too).

 

Today I tested the adapter for NBM. I called it "hard rock adapter". This adapter is installed in place of the tubes. This adapter turns the NBM into a quasi hybrid amplifier. Perhaps this adapter will also work in ZDT-Jr
The result is the bass is as dense as the impact of a horse hoof to the head

In the near future I will manufacture this adapter in a civilized form and will show you dear friends. Now it's an ugly pile of components and wires.

 

I'll consult with the manufacturer tomorrow. Hope the difference negligible or its there is no.

 

I consulted with the manufacturer.
Without any alterations at all, my adapter will only work on the first version of NBM. I have this version.

In other versions of NBM&ZDT-Jr, my adapter will also work, but a little intervention will be required. On the PCB, you need to remove one capacitor and put a wire jumper instead.
I will be given a real ZDT-Jr - 220v for testing and I will be able to show the whole process in photos.

 

Is the one I bought from you a "first version"? What do you expect these motherfugly adapters to cost?

 

As far as I know, the first version is amplifiers released in 2008-2011. Your amplifier is made much later.

I have not thought about the cost of the adapter yet, as the work is not yet completely finished. But I don't think it will be expensive. The adapter is simple.

 

The first image of the adapter.