Anyone experienced the Luxman MQ-300 or/and The Air Tight ATM-300R?

Charles is on the right path and the answer is no. 

Keithr,
I looked up the speaker’s specifications and sensitivity is 91db and impedance load is 8 ohms with a minimum of 6 ohms. So sensitivity is really  on the fringe  borderline. The speaker load is a relatively easy one. Room is 14 x 16ft .

If the OP is really interested in using a SET amplifier I’d suggest considering a good quality 845 ,805 or 211 output tube based amplifier. In the Dagogo review by the "Beatnik" he used four amplifiers and said that the best sound was achieved with his First Watt S.I.T. 3 which is an 18 watt solid state amplifier.

The above mentioned/recommended tubes will provide typically 20 to 30 watts (845 And 211). The 805 tube will yield 40 to 45 watts as an SET. Of course with these SETs the quality of the output transformer and power supply are major factors to recognize.

Back to the OP’s question, I believe he’d need to hear the two esteemed 300b SETs with his speaker (Or one with very similar specifications ) to determine if the pairing is feasible. I'm a 300b aficianodo but in this circumstance the bigger higher power  transmission output tubes may be more suitable. 
Charles

Thanks ! I think it would probably be worth the try as I am using a MQ 88 U se right now and I rarely push my pre pass 9 o’clock .

H_bomb,
Your current amplifier is a 25 watt push pull circuit. So probably about 4 or 5 db more than the 8 watt MQ-300. If you’re listening at your typical SPLs with the volume control (VC) at the 9 o’clock position it suggests that there’re is excessive gain in your system. You would want to utilize much more range with the VC.

Interesting the 8 watt MQ-300 is nearly double the weight of the MQ 88C!! This certainly tells you something about the size (And presumably quality) of the transformers and power supply section. As I noted yesterday the Luxman MQ-300 seems to be an all out effort premium tier  SET amplifier. 

What are your typical listening levels in your 14 x 16 ft Room? You have nothing to lose with an audition with your speakers. This would settle the matter one way or the other. 
Charles

Hi.I listen at low to medium volume.