I did not purchase this item from massdrop which I am guessing is a requirement for leaving reviews, so I will post it here.
A review for the rest of us:
If you are a hardcore tube amp user then I would suggest you skip this because this is not for you, this is for those people that are like me, a noob with tubes that has no clue.
First let me say that this was not my first tube amp, the first time I purchased a tube amp I figured I would go big, buy the best rated, expensive, and best reviewed with the most tubes because all of that would mean I am getting the best tube amp I could get... correct? Maybe.... but I wouldn't know because I had no clue what I was doing, listening to or listening for. Tube amps are not as simple as plugging in your headphones and BAM! all new sounds and stark differences. I quickly found out that no matter what I did or what tubes I put on it, I wasn't getting that, so of course I had a faulty tube amp and immediately sent it back swearing that everything I read about tubes was a bunch of crap and a waste of time and money. After spending some time with high end headphones and a decent dac/amp, I began to hear the changes in music quality and when going back to my $30 and $80 headphones I could immediately tell the difference and understand what I was and was not hearing. It was at this point that I thought back to the tube experiment and decided to try it again, but instead of going all out and spending top of the line money for top of the line equipment I decided to look around for what was believed to be a good starter tube amp, enter the LD MKii.
(all explanations from here forward are my noob terms and do not require expert dissection and argument)
LD MKii - black box with box and four tubes on top. Blue power led, audio jack and volume on the face.
[what the smaller black box encases is beyond me, nor do I care at this point. All I know is it works for me]
Tubes - Large tubes are power tubes, Small tubes are pre-amp tubes.
[This is where the magic happens, there is more to it but it was in *"tube rolling" that I found my sound]
Headphones - Here is another thing that I did not understand where tube amps are concerned, for best results, dynamic driver headphones are the way to go.
So now that I was armed with my HD800s, HD6xx, 1More triple driver and the LD MKii I started plugging things in and checking the sound.
First thing I did was try it with my Sanskrit pro and then with my Aune X1S while cycling through my headphones on each. There was a slight difference between the two but to my ears (which are admittedly compromised) it wasn't enough for me to say you should use one over the other.
Next I took a few days to listen to different types of music and compared it between the tube amp and Aune X7S because the X7S has an balanced xlr connection that I love on my planars. As I did this I began to hear the subtle differences and where the tube shined and where it did not. To me, the tube and my HD6xx were the best match based on what I like.
Lastly, I began the task of *tube rolling. I did some research and found some of the more popular tubes that are paired with this amp. I eventually settled on the 7-Pin GE JAN 5654W for my pre and the Novosibirsk 6N6p / 6H6pi for my power. This pairing gave me the most amazing improvement on sound, again, based on what I like. I love all genres of music and have found that when listening to jazz, blues, quartets, trios, Cello, and classic rock (AC/CD, Metallica, Eagles and many others) that the combo flourished. The beauty of the sound in its fullness, warmth, separation and clarity was absolutely stunning. I will listen to other genres such as EDM and others that actually sounds better on my LCD 2 Closed to my ears. I have watched movies and it performs great in that space as well but again, it depends on the the type of movie it is, would I use it for Jurassic park or an MCU movie, sure, but again, I would prefer the LCD 2 Closed for that. The point to all this is that while you can buy a dac/amp combo or individual unit pairings and get perfect sound and balance, the tube will take the edge off of the perfection and dirty it up but in a most wonderful way. Tube amps are more about the perfection of imperfection like smudges on charcoal art and mayonnaise in a cake recipe. You wouldn't expect it to work but then you try it and you get that WTF moment when you realize how good it is. To me, the beauty of this amp is its simplicity and ease of use. Are there better amps out there, sure, but from personal experience, the LD MKii is the most inexpensive, easy to use introductory tube amp that will give great results.
Annotation *Tube rolling does not mean place it on your desk and roll the round tubes across it over and over (you laugh but that is exactly what I thought it was until I looked it up). As best I understand it, rolling is when you install different types of tubes (they come with different materials and resistances) to get a different sound profile. You can mix and match different power and pre tubes to one another, but, never mix and match them to itself. From what I understand, you want your pre tubes to be the same to itself and power tubes to be the same to itself. Mixing them across brand and type to itself could have catastrophic consequences for your tubes and even the amp.
Next thing of note is that you will want your tubes to be tested and matched, I can not explain the how, what and why but from everything I read, that is the best practice. Tested and matched means that the type of tube (pre or power) will be a tested and matched pair to itself not across types.
Last thing I will say is that there is a jumper inside the unit that will effect the power output. I have not tried it and would suggest that if you feel you need to do this, go check out some of the reviewers that do a deep dive into the LD MKii, there is a lot of good information about this unit out there so don't be afraid to look it up or even ask questions because it is better to ask when you don't know than to assume and possibly cause irreparable damage. I hope this helped and congratulations for making it to the end of my never ending post.