So I've got my pair up and going in an uglycase without the input attenuators; haven't found time/money (mostly money) to order the vactrols. When I do, I'm going to get 500-ohm pots and parallel them with a 750R to get the 300-ohms; the only 300-ohmers I found were unreasonably priced.
Haven't added the 8k2 parallel resistance that another gentleman referenced earlier (and is referenced in the urei documents), but I noticed something funny. In one channel, I definitely get the oscillation(?) when flipping the gain switch down to the lower setting. However, in the other channel, setup with the same passives, there's no oscillation. Is this something that is influenced by the transistor's HFE, perhaps? I'll match a pair and experiment in due time, probably once I get the vactrols and pots ordered, but thought I'd ask any experts/passionate twiddlers out there for some insight in the meantime.
I can only use them for very quiet things without the attenuators, of course, but what I have tried (mostly nylon string guitar and voice from about 3 feet away with a dynamic mic) sounds great.
Oh, and I yanked out the zobel indicated on the silkscreen(which is for the cinemag mentioned in mnats first posts) and installed 150k resistor for the Jensen 115ke inputs I'm using.
Just thought I'd add my experiences to the pile. Definitely would be interested in building another two channels for a 4-pack at some point, if and when they become available. Thanks for the opportunity to experiment on this, Mako! You're a gem-encrusted Prince of a human being.
Ben