Danny,
I am about to purchase a Dac-60 that was one of your first sent out with stage 1 mods from another AC member, it has a black face plate. From research, I found some of the early stage 1 dac-60s from GR-research, were sent out before the stage 1 mods were finalized. The seller mentioned when he purchased the dac (used also), he had the same questions, and already verified with you what the differences were. Some of the early dac's were sent out without a tube upgrade. The original owner of the unit replaced the stock dac-60 tubes, with a pr of Jan Phillips tubes, and that is what is currently in the dac.
Do you think the JAN Philips are an o.k. match for the dac-60, and if not are there any you would recommend? Not sure if this qualifies as giving up proprietary info on your mods for the dac, if it is, understood if you don't want to provide give your opinion on tubes for the dac-60.
Thanks,
John