I use the Modwright Anniversary PreAmp with the Modwright KWA 100SE Amp.
A match made in heaven!
I really suggest you use a tubed PreAmp with your Modwright KWA 150SE.
Talk to Dan about this!
I did have an older but reworked MW SWL 9.0 SE with upgraded caps, NOS tubes and tube line power stage (I think that is what it was called). I bought it used from a local dealer and when I had it paired with my Dynaudio Special 40 speakers it was awesome. Made the SP40s really sing. I recently upgraded to Spatial Audio M4 Sapphire open baffle speakers. In order to save the tubes I took the preamp out of the chain and hooked my Lumin T2 directly to the KWA 150 SE and as the speakers broke in I was very pleased with the sound. Excited to hear them with the preamp back in the mix and I was very surprised, it added very little to the sound. It made a huge difference with the SP40's but very little difference with the M4's.
The SWL 9.0 SE was my first experience with tubes and while I loved what they did with my SP40's I didn't like turning the preamp on/off, waiting for it to warm up, worrying about the tubes wearing out, etc. I planned on dealing with it with the SP40's because of how much better it made them sound, but with the M4's that is not the case. Given that I would prefer to go with a SS preamp or possibly well the KWA 150 SE and get a nice integrated. That would probably be the way to go, but I really enjoy how the KWA 150 SE sounds, not sure if I can find that in an integrated without tubes.