Paul at Tube Research designed the circuit for the First Sound pre-amp as a favor to his friend, Emmanual Go, owner of First Sound. Friends or not, I can't imagine him giving Emmanual a circuit as good as his. Sonically, there is a difference.
The MP-1 is a fine pre-amp but lacks the soundstaging, dynamics and resolution of the TRL GTP-3 pre-amp, IME. Of course TRL has offered the GTP-4 pre-amp for the past 18 months that is much better. I'm patiently waiting for mine, which I don't mind. I know what I'll have when it gets here.
I suggest auditioning the TRL if you can before settling for anything else.
The MP-1 is a fine pre-amp but lacks the soundstaging, dynamics and resolution of the TRL GTP-3 pre-amp, IME. Of course TRL has offered the GTP-4 pre-amp for the past 18 months that is much better. I'm patiently waiting for mine, which I don't mind. I know what I'll have when it gets here.
I suggest auditioning the TRL if you can before settling for anything else.