One of the Coda Contiunuum Preamps or CL or CLX... (these are all nice sounding)
Audio Research LS9, LS12
Muse Model 3 Signature
Classe 5 or 6 or CP47 or CP50
I suspect that the Gustard recommended would be good for the buck $700, but to be fair, I've never heard it.
I hope this helps, Tim