Pre Amp for Pass Labs X150.5

The Capri would likely work very well. Buy one used and try it. Re-sell it if it's not to your liking.

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

besides the impedance matching, i read that the gain also plays a part. just don't know how, someone pls enlighten me.

the X150.5 has a gain of 30dB, say the pre has a output gain of 14 dB, what does this mean? what if the pre now has a gain of just 4 dB?

thanks

It simply means you'll turn the volume knob farther on the 4dB preamp, and you may have smaller steps in volume versus the 14 dB preamp. In other words, the 14dB gain preamp will get louder faster than will the 4 dB preamp, and the 14 dB preamp may get too loud, or be too loud, at a low volume control setting.

30 dB gain on an amp is toward the high side from my experience.

just to make sure i get it right. X150.5 has gain of 30 dB and Balanced input impedance of 30,000 Ohm. say i have 2 pre:
A) Balance Output Impedance of 750 Ohm, Gain of 4 dB, every step in volume increment is 3 dB
B) Balance Output Impedance of 80 Ohm, Gain of 14 dB, every step in volume increment is 0.5 dB

Preamp B would give more control and play of the volume right? i.e. I could play my system late at night without getting too loud.

how does the output impedance affect the outcome?

thanks