Gotta love Nelson Pass

^Yes, even some of the Pass Labs branded amps, like some of the Alephs have some limited applications.

Right, current source amps vs. volage source amps is a big difference. 

Active gain preamps vs. passive preamps with no gain at all is a big difference too. He has passive preamps which became active after the volume turned up to 9 o'clock (the aleph L series). 

But if you know what you need for your particular speakers then it's a benefit. For example i don't need much power for my full range crossover-less speakers with 101db sensitivity. Nelson said he use Zu Audio speakers himself (among others). So for my need current source F2J power amp of 5w per channel is enough. And absolutely neutral First Watt B1 buffer preamp (pretty small box) is good match for F2J power amp. 

Everyone should learn more about FW or Pass Labs products, but Nelson can help with a great support for his products. 

 

I used a B1 and a First Watt F3 amp for a while with my Superflys.  I called the B1 the Transparency Machine.  It works great but it's neutral and revealing as all get out, as if you are plugging your source straight into your amp.  So much so that a CD player I thought was reference level turned out to be much less so, LOL.

@whoopycat i guess so, but my source is analog only, no digital. Phono preamps will be connected to First Watt B1 buffer and it would be nice to judge the actual quality of the cartridge+phonopreamp.