Well here's the next step up: The DC Coupled B1. This is not designed by Nelson Pass, but by folks over at diyaudio. Pass designed the simple B1 circuit to foster and encourage experimentation, so it has his blessing. The difference between this and the standard B1 is the elimination of input and output caps and the inclusion of a much praised shunt regulated power supply. So I can chuck the battery power and go back to good old ac.
Many thanks to Salas, Tea-Bag, and all the other extraordinary minds and helping hands over at diyaudio - the two B1 threads there are the few that actually stay on-topic and don't try my patience.
Be warned: These threads are loooong.
http://www.diyaudio.com/forums/pass-labs/145201-building-symmetrical-psu-b1-buffer.htmlhttp://www.diyaudio.com/forums/group-buys/147075-gb-dc-coupled-b1-buffer-shunt-psus.htmlThe cost to build is slightly cheaper to much cheaper - mostly due to the very cheap pcb ($7) and depending on the quality of caps, etc. you use for the standard B1. On the other hand, there is some tricky component matching involved like the fets and the LEDs and a larger parts count.
These PCBs are no longer available but a larger and more accomodating (and twice as expensive) PCB is planned for the end of July. If interested you'll have to sign up in the DC Coupled B1 Group Buy thread in the Group Buy section of diyaudio linked above.
Too early for serious opinion, but given the lower quality connectors and slap-dash nature of the build it sounds very impressive. The overall signature of the standard B1 remains, transparent and clean - but kicked up a couple notches.
