Definitely a killer, and pro preamp.
1073 purists will argue that this isn't a true 1073, but a 1272 because it only has 2 gain stages, not 3 , and in some senses, that is correct. But there is also purists that say its not a 1073 sound if the EQ isn't part of the circuit, and that's also a way of looking at it. Read more
And then there is the rest. Another thing is this. There was a coupling capacitor that had to be negated in the 500 series version. How much that affects the sound, Im not sure, but all I can say is this. When you forget about all that, and take it for what it is, its one of my favourite preamps, and it sounds wonderful. I especially love them on Vocals, Electric Guitar, Overheads, Snare, and Room mic's. And also, all the Purists talk aside, I can also say this. I have known engineers, and heard from engineers that they consider BAE to be the best and closest replacement to an O.G 1073. I do think the Rack and or Version with EQ will get you a little closer to the originals, but also the 500 series(despite some changes) are absolutely killer, and as long as BAE keeps using Carnhill Transformers and keeps them Through Hole, they will have a home in my rack, and I would buy another and recommend them. Fat low end, thick and balanced midrange, sweet and silky highs that are just perfect, not super bright, but never sounds to dark to me. Drive the input Harder and you definitely get that nice Compression and Bloom. Like I say, taking it as it is without comparing, and Its a beauty. Compare it too much to the O.G, and it may fall short.