Pre Amp for Pass Labs X150.5

Hello, I'm running a pair of Pass Labs X600.5 monoblock amps, which, like your X150.5 amp, have an input impedance of 22kohms balanced, and a Pass labs X0.2 preamp. The output impedance of the Pass Labs XO.2 preamp is 200 ohms unbalanced & 750 ohms balanced. You could buy a Pass Labs X-1 preamp for around $2200 used or try the JR Capri preamp that everyone is talking about--(assuming the output impedance of the Capri matches). Also, depends on if you want to go solid state or tube. Sounds like you are leaning toward tubes. To narrow the playing field: First, make sure that the output impedance of your new preamp is a good match with your Pass amp. Second, try to determine if there would be a musical synergy between the two components. The second part is the harder (and fun) part. Good luck! Stan

Hello Driver, To my knowledge preamp output impedance doesn't effect volume. Matching of impedance just assures that the entire audio signal is passed. I looked up your X150.5's input impedance last night @ the Pass Labs website. According to Pass, your amp's balanced input impedance is 22 kohms, just like my X600.5 amps. The gain of my amps is also 30 dB. My Pass Labs X0.2 preamp has a gain of 12 dB balanced, while my old Audio Research Reference 3 preamp had a gain of 11.5 balanced. Both worked well with my system as far as volume goes. If a gain is very high, like a VTL 7.5 markI preamp which has a gain of 20 dB balanced, for example, then you can run into high volume problems no matter how low you set your preamp's volume. Also, with the VTL 7.5 markI, it would depend on an amps output and the amps gain, plus the sensitivity of speakers, etc. However, most preamps have a sensible gain and aren't as high as the VTL 7.5 markI. Hope this helped. Stan