Hi Trelja, thanks a lot for your useful feedback! I learn a lot about Jadis amps from the comments you made in other audiogon threads.
My Cayin A-50T amp was previously used to drive a pair of B&W 683 speakers (90db). Most of the time the amp was operated in triode mode (16wpc), which produced a clear and lively sound. If switched into ultralinear mode (35wpc), the amp became more powerful with very solid and strong bass, but sounded a little bit harsh to my ears. So for the high sensitivity B&W 683 speakers, 16 wpc was enough to listen to most albums I have.
Recently I updated part of my system. The speakers were replaced with a pair of Proac D15. I like the new speakers, which give a much softer and cleaner sound, better image and a bigger soundstage. Strangely, many albums that sounded lively with the amp operated in triode mode became liveless, lacking of dynamics. Some improvements can be heared when switching into ultralinear mode, but still not good enough for me. I suspect that the amp is not powerful enough to drive the Proac D15 that has a realatively low sensitivity (it is low, but should not be hard to drive???) That is the reason I want to update the amp. The famous Jadis brand is my first choice.
I don't have a chance to pair the Proac D15 with a JOR or D50. If so, it will be much easier decision for me. One attractive thing about JOR is that it accepts both EL34 and KT88 tubes (should sound different). I learned from previous threads that the ONLY thing that needs to be done when swapping between these two different kinds of power tubes is manual biasing, is that correct ？？？ Tube biasing is not a big issue for me.
For the DA50, it only accepts KT88/KT90/6550 (same tube family), and I can not play around with my NOS EL34 tubes. However, if the DA50 does sound much better than JOR when paired with the Proac D15, I will have no hesitation to go for it !
