I don't have any experience with the Decware linestage, but, I do have a few suggestions on what to consider in your choice of linestage. From a practicality standpoint, I always turn off tube gear when it is not in use. But, because solid state gear, particularly amps, take an extremely long time to warm up and sound their best, I would leave such gear on even when it is not in use. There might be problems with using a tube linestage with a solid state amp that is left on all the time because of the possibility that the tube gear will emit loud noises/pulses when being turned off and on; if one can mute the linestage for turn on and turn off, that might to be a problem, so that is something to look into about your prospective purchase.
I hope that Decware will allow you to audition their linestage with your amp. While an audition is really important for ANY purchase, it is particularly important when one is trying to match a tube linestage to a solid state amp. I have found that, even when the match is theoretically fine (i.e., low enough output impedance from the linestage, short interconnection cable), the result can be quite unpredictable (more unpredictable than the other hybrid approach of solid state feeding tube amp).
I hope that Decware will allow you to audition their linestage with your amp. While an audition is really important for ANY purchase, it is particularly important when one is trying to match a tube linestage to a solid state amp. I have found that, even when the match is theoretically fine (i.e., low enough output impedance from the linestage, short interconnection cable), the result can be quite unpredictable (more unpredictable than the other hybrid approach of solid state feeding tube amp).