Pure Class A SS vs Tube Amp

now I need deal or recommended dealer

Based on my experience and a great many others that have been reported here I would **very** highly recommend Reno HiFi.

Good luck.  Regards,
-- Al

Lordrootman 2-28-2020
Now I’m thinking about XA 30.8
since eventually I may move to focal Electra 1038 when my 4 months twins grow little bit
I want separates and I really want to keep my Michi P5 Preamp gain is complicated with first Watts J2

The Focal Electra 1038be is of course a very different animal than your Klipsch speakers, and I doubt that an amplifier choice can be found within a given price range that would be optimal for both. And specifically I suspect for a variety of reasons that the XA30.8 would be a much better choice for the Focal speakers than the First Watt models you have been considering.

And in that regard I recall from some years ago that a member who no longer posts here but for whom I have great respect very successfully paired an XA30.5 with a comparable Focal model.

However, as has been said the 26 db gain of the XA30.8 could very well be problematical given the gain of your preamp and the sensitivity of the Klipsch.

So here’s an approach to consider, if you believe that changing to the Focals is a real possibility in the foreseeable future. If you purchase the XA30.8 (or some other amp providing comparable gain or more), and you find that the gain is unacceptably high for use with your preamp and the Klipsch speakers, insert a pair of Rothwell attenuators at the inputs of the amp. They are offered in both balanced and unbalanced form, and with a choice of 10, 15, or 20 db of attenuation.

Some members have reported here that Rothwell attenuators seemed to compromise dynamics in their systems, while others (including me) have used them with no evident side-effects. I suspect that impedance considerations have contributed to at least some of the disparity in those findings. And if so the 50K/100K unbalanced/balanced input impedances of the XA30.8 and the 470 ohm/100 ohm unbalanced/balanced output impedances of the preamp would seem encouraging in that respect. But in any event you would presumably just be using the attenuators temporarily.

Finally, I would recommend against any make of inline attenuator other than the Rothwells, as the others I am familiar with have unreasonably low impedances for most consumer (non-pro) applications.

Good luck. Regards,
-- Al

The J2 does in fact provide XLR as well as RCA inputs, according to its manual and the description at the First Watt site.  I'm thinking that you might have been misled by photos at the Reno HiFi site which are shown under links referring to the J2, but which actually depict the F6.

The Pass XA amps other than the XA25 provide balanced as well as unbalanced inputs, but while the XA25 has a gain of 20 db, all of the other XA amps have gains of 26 db, which as has been said is most likely too high.

Good luck.  Regards,
-- Al

... my new preamp Michi P5 is class A design

@glennewdick makes an excellent point about usable volume control range. And that is a particularly important consideration in this case because the Rotel Michi P5 preamp has high gain. According to my calculations its gain is at least 16 db, and it may be considerably more than that depending on the combination of RCA and/or XLR inputs and outputs that are used. But even 16 db is well above average for the gain of a line stage.

Power amp gains generally tend to be in the area of 25 to 30 db. Your A21+, for example, has a specified gain of 29 db. But given the high gain of the preamp and the high efficiency of the speaker I think it would be prudent to avoid power amps having gains of more than about 20 db. (The gain of the XA25, btw, is 20 db; many of the First Watt amps have gains that are significantly less than that, which would be fine in this case).

Power amp gains are often not specified, but they can be calculated to a good approximation from the sensitivity spec that is usually provided, in combination with the specified maximum power ratings. Online calculators may be available for that purpose, or you can post back if you’d like to me to described how to do that calculation manually.

Finally, btw, virtually all preamps (and other line-level or phono-level analog components) operate in class A, even though some manufacturers trumpet that as a selling point.

Good luck. Regards,
-- Al

It appears that the KLF 30 is actually rated at 102 db/1 watt/1 meter, and given the horn loading of its mid-range and high frequency drivers I suspect that rating is reasonably accurate.

A concern such high efficiency raises is that the noise performance of the amp that is being used becomes especially critical. The hiss levels produced by some amps which may be perfectly fine with say 90 db speakers could very well be bothersome with 102 db speakers.

FWIW I suspect that the solid state Pass XA25 I use would be fine in that regard, as it is extremely quiet with my speakers that are spec’d at 97.5 db. I have no idea, though, how its very transparent and somewhat tube-like sonic character would synergize with the sonics of the KLF 30. But in any event, before settling on an amp it would be prudent, IMO, to try to verify that others have used the particular amp successfully with comparably efficient speakers.

Good luck. Regards,
-- Al