The SR-71 seems like a very well thought out design, aligning some features off the original 670 schematic to modern needs.
However, it´s not an exact replica of a 670 as the Drip Versions are. I don´t wanna say, that leaving out the lat/vert Mode, exchanging time constants and of course using much cheaper and easier to gt 6BA6 Tubes instead of 6386 is a bad idea, it´s just a different approach, while Greg´s design tries to be very close to the original.
There are some other very good 670 redesigns, some leaving out the tube based AMP stage, getting relay based hard bypass, some focussing on slimming down the general design or making calibration easier. The Fairchild 670 mk II would be a great example of one of these newer designs.
And I also agree that the Drip Units (especially Version 1 with the huge PCB) aren´t made to be shipped around a few times - but that´s not a critical point with these units, is it? I bet most of the people make these for themselves and don´t think about reselling them.
But, to bring this thread back to topic - the UE-100 is a much more clever design shippingwise with it´s 10 modular PCBs. Let´s talk about that one.
Does anybody power his unit up already? I´m still waiting on instructions for Drop Resistors.