Joined drop but don't understand pricing for additional tubes. Also I want to buy more tubes on Massdrop but the system allow me to select only one option. Cmon Massdrop you can do better and 2x cheaper than this.
It isn't an option for additional tubes, it's an option for alternate tubes that should sound better than the ones the ones the factory uses, but they also cost more than the factory cheapos. Your best bet for purchasing additional tubes is eBay. Search the following on ebay.
2x Russian 6H6P-I Power Tubes Little Dot Amp Mk II 6N6 from the yenaudiostore: A good power tube (the big tubes) and better than the factory set. I suggest yen audio because its an easy place to start, but you can find the same thing from tons of different sellers. I like yen because they are reliable. If anyone else has tube seller recommendations I would like to hear them.
2x Voshkod 6ZH1P-EV Matched Pair Little Dot Amp from the yenaudiostore: My favorite signal tube (small tubes) for the Little Dot MK II.
Matched Pair NOS/NIB Mullard 5654/6AK5 BLACK HOLE plate tubes - Little Dot: Also a great signal tube.
This would be a good place to start, and with these signal tubes you don't need to change the jumpers since they are both in the EF95 Family. Here is a link to a fantastic tube rolling guide for the Little Dots. It's been a great reference and I've tried quite a few of the tubes (I've stayed in the EF95 Family)
https://www.head-fi.org/threads/little-dot-tube-amps-vacuum-tube-rolling-guide.563884/
Hope this helps. Let me know if you have any additional questions.