Update 2015-12-18: Things improved quite a lot by simply wrapping the board in aluminium foil!
The amplifier phase noise floor is now at around -156 dBc/Hz while the 6502 is at -163 dBc/Hz. The AM noise numbers are similar.
Original post 2015-12-17: I put together a first prototype (only one output channel) of my TADD-1 inspired frequency distribution amplifier. Preliminary schematic here.
I compared the prototype board to two commercial distribution amplifiers: an SRS FS710 (quite awful) and a Symmetricom 6502 (very good). I also compared my new data with John Ackermann's measurements from 2007.
The new board showed ugly spurs at 50 Hz and harmonics using an el-cheapo wall-wart 12 VDC SMPS, so I also tried it with an "ultra-low noise DC-source" a.k.a 12 V lead-acid battery.