Amp for Kef Reference Speakers 203/2

[ant1973]

I recently acquired a pair of Kef Reference 203/2 speakers for a knockdown price. I have been away from hifi for a long time and have tolerated various Sonos products based on their convenience.

Having recently moved home, they are in a room which is 11m x 4m. No furniture as of yet, and lots of hard surfaces, so I know that will limit the sound somewhat.

According to KEF the speakers have a sensitivity of 89db (2.83v/1m), a maximum output of 113db, and impedance of 8 ohms (3.2 min). 50w - 250w Amp is recommended by Kef.

I set the Speakers up with an old Roksan Kandy Ka1-111 which is 20 years old. From what I can make out, the amp delivers 115wx2 into 8 ohms or 220x2 into 4 ohms. Damping factor: 110, 38 db gain. Source was an old Sonos Connect Amp using pretty thin RCA connectors.

I set the Connect Amp to max volume and used the Kandy Amp to regulate the sound.

The speakers to my ears (admittedly aging) sounded fantastic. Sounded a little shrill with some female vocalists at the 9-10 position on the amp. But with others it was fine. 10 oclock sounded plenty loud on the amp.

Having looked at the Class D amps, I was toying with trying a pair of Fosi V3 Monoblocks or a Nord NC252 Amp.

I don't need the amp to go all that loud, but did wonder if some of the shrill sounds were really distortion as volume increased. I get that room accoustics are a big part of this.

Am I wasting my time trying either of the above amps? If so, what if anything would you suggest.

Thanks in anticipation.

 

[AnalogSteph]

I don't need the amp to go all that loud, but did wonder if some of the shrill sounds were really distortion as volume increased. I get that room accoustics are a big part of this.

From what I understand, a Sonos Connect AMP is an integrated amplifier with speaker outputs all of its own, so as a sanity check I would try operating it standalone and see whether that makes any substantial difference.

Fundamentally your combination does look workable and adequate (even if the Roksan looks to be an IEC Class I device when can get annoying, but I assume the Connect Amp is a Class II - double insulated - device with no wired networking in sight). I would probably back off the levels on the Connect Amp a bit since a max required level of 10 o'clock on an integrated amp with somewhat less than average gain seems a bit low. You should still have 16-20 dB to spare by 12 o'clock, so there is absolutely no reason to restrict yourself to such a small control range.

Sonos appears to have very limited ReplayGain support (it's only reading track gain, which is annoyingly limited and close to useless in my book), but this could fundamentally help. I suppose one could try streaming to it via Foobar2000 with the uPnP Controller plugin or similar.

 

[ant1973]

Thanks, I should maybe have made clear that the Connect (as distinct from the Connect Amp) essentially just functions as a DAC. It's a long discontinued product. Will dial down the Connect volume and report back.