Jadis JA-30 vs JA-50 need opinions

You will not get an answer as long as you do not point out what you want to use those amps with. 10 watts more or less generally do nor make much of difference as far as the sound is concerned. There are exceptions, but they are fairly rare.

Yes I know, I didn't give much info, but it was actually a bit on purpose. I know people will tell me I need more power for my 86db speakers to be able to play loud enough but I have never even been close to miss watts when trying different amps, not even with a 40w class AB tube amp. Not when it comes to playing loud, bass control is another thing. I wanted to know if anybody knew the sound difference of the two amps but I guess it was a long shot. Would still be very interested though!

I'm going from years back, as I haven't kept up with current production, but I believe the JA 50 uses KT90 tubes, where you could use EL34s, 6550s and KT 88s with the JA 30s. IMHO the Jadis amps using KT90 tubes sound perhaps cleaner than the other types, but ultimately uninvolving in comparison. With the right speaker, the JA 30s I have heard could be magical, particularly with vintage EL34 tubes, but they probably will not give have as much control on the bass as the KT 90s do. KT 88s in a JA 30 might be a good compromise between bass control and midrange magic.