First, I have not heard the sr-71 nor the Ety/ Eddie Current combinations. I owned the hd300 and auditioned the hd25. I liked the hd25 version of the Eddie Current amp better than the hd300 even with the senn 650's. I thought the hd25 had more openess and transparency. I eventually decided there was a sameness and darkness to the hd300's sound, despite much tuberolling, that soon wore on me. I am not sure where I put the gilmore lite in comparison to the hd25. I usually prefer tube amps but I especially liked what the gilmore lite did with the senn 650's.
The lite has a flat soundstage presentation though, which is the amps only noticeable shortcoming from my perspective. So right of the bat, if a sense of space is particularly important TO YOU the hd25 would be better for you. The hd25 is richer sounding too, but not a lot more. Both amps have excellent dynamics. The hd25 has the advantage in features having a preamp output, multiple inputs and the same loop out feature the lite has; but it also costs twice as much.
As you may expect the lite is more neutral with a seamless frequency response that has more apparent extension at the frequency extremes and a powerful bass response. I dont find the lite more transparent but its does sound a little clearer. The lite's treble is very refined and this quality especially endeared the lite with me. Another characteritic of the lite was a definite forwardness in the mids that removed any hint of recessiveness in the 650's midrange. The lite's forwardness gave the 650's a rocking quality I have only heard through my singlepower amps when equipped with the best tubes. However, I listen to mostly rock and electric blues so be aware the senns performance on rock is more important to me in my evaluation. Both amps have seperate power supplies and are very quiet. I give the blackness edge to the gilmore lite, however, even with the std power supply.
If I were going for a headamp only to use with the 650's, the lite is one of the best combinations of performance and value out there. Furthermore, the lite works well with grados and my very similar gilmore v1 is also excellent with beyer dt880's and any other headphones I have tried. If small size for tight placement requirements and portability is a need, again the lite is the clear choice. In addition, an upgrade power supply can be added now or in the future to improve the lite's performance even more.
If I were in need of a preamp or the combination of features the hd25 provides, desired that richer tonal quality of tube sound or desired a more open soundscape I would go for the hd25. The cost is double, but the hd25 is a complete control center as well as an excellent sounding headamp. The only reservation I have with the hd25 is the way the tube sockets are board mounted. I dont like how removing a tube causes so much board flex. For someone like me that likes to tuberoll this was disconcerting. Even with the standoffs there is to much flex for me.
I find both the gilmore lite and the hd25 excellent amps. Take your time examining your own priorities be it sound, features or price. Audition them if you can. IMO, whatever you choose you will be pleased.
