Hey there everyone. I have a Little Dot Mk3 and after owning it for some time now, I decided to share some of my tube rolling experiences. I did not roll a lot of tubes, it's a very small number of tubes, but the results surprised even me.
After tube rolling the Little Dot Mk3, I can pretty safely say this is an amplifier that benefits incredibly from a change of tubes.
All of these were heard using my DIY planar magnetic drivers and headphones
Many would consider this not a good idea, but after finding out that I managed to make my DIY planar drivers have an impedance curve nearly identical to a dynamic driver, it also has the same properties with different output impedances. This means the tubes can affect the sound just as much as dynamic drivers.
(Impedance is 42 Ohm, sensitivity is 108dB/mW)
I did not experience any distortion issues, low volume or anything bad using planars. (Even with EF91 tubes)
m.y. = Manufacturing Year
Power Tubes
The main thing I noticed is, that Power Tubes mainly affect the bass and that is about it.
JJ 6SN7 (m.y. 2021)
These JJ 6SN7 tubes are quite incredible for their cost and a fairly small size. They really made the sound quite a bit more punchy in the bass.
PSVANE UK-6SN7 (m.y. 2023)
I have not seen these tubes mentioned a lot - honestly I didn't expect much of a change and one of the reasons I got them was simply the 300B look they have. But then I turned on the amplifier with them and I was genuinely surprised! The bass felt way smoother compared to the JJ ones. (smoother in the way that it did not feel as if it jumped up and down in a few different places under 100 Hz). One more thing I noticed is the subbass being able to go a lot deeper.
Driver Tubes
Now this is where a lot of the fun comes in! The driver tubes change the sound from the ground up.
Voskhod 6ZH1P-EV (m.y. 1955) (EF95)
After reading the article for the first time, I was thinking for a very long time which tubes I'll end up going with. I'm glad I went with the Voskhod 6ZH1P-EV. It's a very safe choice. The soundstage is great (definitely not the widest though), the imaging is very precise. I found the bass not being super punchy with these, but it was very warm and pleasant to listen to. The mids felt very focused and smooth. The treble sometimes felt a bit bright in some areas, but in some of them it felt darker - safe to say, it was quite a rollercoaster in the treble area. In the end they were the most solid state sounding tubes out of the bunch with there not being a very big difference compared to my Topping EX5. If someone's new to the tube rolling, I can safely recommend these tubes.
Mullard M8161 (EF92 text on tube) (m.y. unknown) (EF92)
The main post is very much accurate. The first time I listened to these, I was like WOW, that's some incredibly quiet background. It makes a lot of instruments sound different than what I was used to thanks to that quietness in the background. The soundstage is way wider compared to the 6ZH1P-EV, the imaging doesn't feel as precise though. The bass is very smooth, it feels like there is a slight boost in the 80-150 Hz area making it quite punchy when the song wants it to be punchy. The mids are just incredible - vocals sound amazing (maybe a bit too close to the ear), the instruments sound incredibly realistic. This tube definitely leans to a warmer sound focused mainly on the mids. The treble is where I unfortuneately start to consider these tubes a bit more on the boring side. In a way, it feels like there is a high shelf filter making the treble go down a few dB and then back up at around 15kHz. I'd consider this tube if you plan to listen for long hours as the darker treble really helps with making the sound pleasant for a long listening time.
Brimar EF91 (Yellow T) (m.y. 1960) (EF91)
The tubes that come directly from the Swiss army - quite a nice origin. If you've read the main post, you know what stands out about these - but if you don't, it's the unique bass. While reading it, it was very hard for me to imagine what exactly is meant by "unique." The moment I put them into the amp and played the first song, I finally understood it. It's not easy to explain, it might actually be near impossible. It's very fun, but uncontrolled, it completely ignores the speed of the planar magnetic drivers. It is the most fun bass I've had out of the tubes I've tried until now. The bass is combined with incredibly wide soundstage, where I could actually feel the distance of instruments from the ear. The imaging felt very precise, though I must say, with these everything in a way felt as if it was coming a bit more from the back of my head instead of all around. The mids on these tubes is very pleasant to listen to - it slightly leans to the warmer side with incredible vocals. With this tube I probably felt the most actual seperation of all the instruments (not to say the other tubes were doing a bad job, all of them do an amazing job, but I found this one to stand out). The treble is interesting - it's definitely brighter in some areas, but it never got sibilant or unpleasant to listen to - rather it made a lot of very small details stand out a lot. I actually noticed stuff in music I did not notice before even through my Topping EX5. This is the tube I'd recommend to anyone if they're looking for an incredibly fun sound with a bit of a different treble.
TLDR
Voskhod 6ZH1P-EV: Most solid state like sound with incredible vocals
Mullard M8161 (EF92 text): The best performer in mids, darker in the treble
Brimar EF91 (Yellow T): A very fun tube with unique bass performance.
My personal favorite combo
PSVANE UK-6SN7 + Brimar EF91
I hope it was interesting to read to at least some of you and that it might help you make your next choice (or your first one if you're new here)
