Amplifier for Guru Junior

Hi All.
I recently bought a pair of Guru Juniors and now looking for an amplifier for them. Can you recommend me something?
I'd like it to be able to play well at low and mid volume level with Guru's.

The source is a Metrum Octave.

Too bad tubes are out. Even though they are an unlikely match the Gurus to me sounded leaps and bounds better with tubes than SS. This was with the QM10-2s I had for a while. Really good! YMMV. 
Like I said. Unlikely match. Played them with Odyssey Stratos Extreme and Jolida Tube Pre and with a Cayin A100T Tube integrated. The Cayin sounded way better with all kinds of music. Opposite of other speakers I’ve had with the same components. Merlin speakers are inefficient too and people almost exclusively use tubes with them. 
On another site they recommend Rega Elex-R, are there any opinions/experience on how Rega works with my speakers?