Mesch makes an excellent point. Dorkwad has recommended a very nice product, that is in your price range, but unfortunately I don’t think it would be a good match for your amp. As is often the case with tube preamps its measured output impedance of around 1800 ohms (unbalanced only) is much too high to be a good match for the input impedance of your amp (10K unbalanced, 20K balanced). And I note that the manual for your amp recommends that it be used with a preamp having an output impedance of 600 ohms or less. Also, its gain is probably too high to be optimal for use with your very sensitive and very high powered amp, especially when playing CD’s. Gain that is too high in relation to the sensitivity and power capability of the amp (with the efficiency of the speakers also being a relevant factor, that apparently being moderate at 89 db/1W/1m for the L150A) would force you to use the volume control too close to the bottom of its range. Finally, although your amp can accept unbalanced inputs in certain ways, it does not provide RCA input connectors, and it appears to have been designed with the expectation that it would be likely to be driven with balanced signals.
IMO your chances of success would be greatest if you were to choose a solid state preamp providing both unbalanced (RCA) and balanced (XLR) outputs. Some of the older Classe preamps such as the CP-50 and CP-60, with the optional built-in phono stage, may be findable in your price range or for not much more, and should be fine choices. Some of the lesser models in that range, though, such as the CP-45 and perhaps the CP-30 and CP-35, may have line-stage gains that are somewhat higher than would be optimal for use with your amp.
Good luck. Regards,
-- Al
IMO your chances of success would be greatest if you were to choose a solid state preamp providing both unbalanced (RCA) and balanced (XLR) outputs. Some of the older Classe preamps such as the CP-50 and CP-60, with the optional built-in phono stage, may be findable in your price range or for not much more, and should be fine choices. Some of the lesser models in that range, though, such as the CP-45 and perhaps the CP-30 and CP-35, may have line-stage gains that are somewhat higher than would be optimal for use with your amp.
Good luck. Regards,
-- Al