Jadis orchestra reference or DA50 for Proac D15?

FWIW, I heard the DA50 Signature driving a larger pair of Proacs (I think it was the 3.8's) at a Stereophile show and it sounded fabulous, not underpowered at all....

All tube amps get hot and generate a lot of heat, same with Class A solid state amps. However, these "small" integrated Jadis amps like Orchestra and DA50 are quite tolerable in heat generation. You will only notice the heat if you put your hand close enough to the tubes.

With regard to whether it will be enough to drive a Proac D15, I think it should be okay since it is a "small" two way floor-standing speaker, with a 6 1/2 inch mid-bass driver.

It seens that I should go for the Jadis DA50, but I am still wondering whether Jadis Orchestra Reference with EL34 power tubes (40wpc) will be powerful enough to drive the Proac D15 with ease ??? I have two set of NOS EL34 tubes from Mullard (XF2), and it is a pity that I can not use them in the Jadis DA50 amp.

The relevant question is, are you satisfied with the way your Cayin drives the ProAc D15? If so, either Jadis will get the job done.

I own a JOR, DA30, and DA60, and would tend to agree with Avguy about the superiority of the DA50S over the JOR, though may differ on the ultimate degree. I would say a lot of it, (predictably) comes from the difference in topology - fixed bias (JOR) versus cathode bias (DA30). That's not to say fixed bias is inferior, as I certainly don't believe that. Obviously, Jadis put a lot more money into the DA50S; reflected in their retail pricing. But, all things being equal (and, when are they ever?), a cathode bias circuit will sound more warm and liquid, though at the expense of power. Further along those lines, getting the JOR to sound the way it can is dependent on having the right tubes, and biasing it properly. While neither amp sounds its best with the stock tubes, I believe the Ei KT90 found in a lot of JORs is an especially bad choice, and hamstrings the amp tremendously from a sonic perspective.

Also, on top of the fixed bias operation, as the JOR operates in Class A/B, whereas the DA50S is more towards Class A (claimed to be Class A, but most amps that claim to be Class actually are not - I need to check the plate voltage and current, it's been a while since I had mine apart), though the more upscale product is going to be at a disadvantage in terms of power on paper, as Avguy mentioned, it doesn't necessarily translate into real world, seat of the pants power.

While both amplifiers provide for one to try a wide variety of tubes to dial in their own preferred sound, you have to take the JOR apart to bias it. That means working around B+ voltages of about 550V. So, if you're not comfortable doing so, you'd want to opt for the plug and play convenience of the cathode bias DA50S.

In the end, if you have legitimate cause for concern about power, you need to step up to a DA60 or DA88S, as the gap there between them and the smaller Jadis integrateds is quite significant. But, presuming the products at hand will satisfy the need, putting all of the above together, I would say the question ultimately comes down to your own personal taste, and again returning to fixed versus cathode bias. If you want a more open and engaging presentation, the JOR is the better starting point. If you prefer richness, liquidity, and an overall more relaxed presentation that many an audiophile will equate with, go for the DA50S.

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 !