The Sony XDR-F1HD is the first tuner in my large collection of tuners that can receive local classical station KPAC without getting a high frequency noise and birdie (like a whistle). I have several other tuners that are not supposed to be affected by unusual subcarriers (including Yamaha T-85 and TX-1000, Onkyo 9090 Mk II, and Sony 730ES) but still are, to one degree or another, only the XDR-F1HD truly fixes the problem. Signal strength is around 60dBF, and adjacent signals do not appear to be part of the problem. Getting rid of this birdie makes it much more enjoyable to listen to this great station, even if, in stock form, the XDR-F1HD sounds a bit dull in the top end, possibly due to about 2dB extra HF rolloff at 15Khz (which can be fixed by removing the capacitors of the crude anti-aliasing filter).
So, for me, this is a keeper. I cut out the top of the case for better ventilation so I can keep it running all the time. I plan to cut out the antialiasing capacitors for flatter HF response, add an HD defeat switch, and add 1.5nF to the backup capacitor for longer storage. One question I have is whether there is a transistor or IC output device that can be bypassed if feeding into a high impedance input. Is a schematic for this Sony available?
I'm not so impressed by HD. On one local college station, the analog feed is head and shoulders above the HD. Though the station is somewhat weak, on a Yamaha TX-1000 it sounds very dynamic and punchy. On the Sony XDR-F1HD, the HD feed sounds soft and compressed to a noiseless 10dB dynamic range. That is, it stays at about -10dB all that time, never gettting louder or softer. I'd love to hear how the XDR-F1HD sounds on that station with the HD defeated.
I don't see much of a case for HD radio. Analog FM radio sounds great (only limited by overcompression and other artifacts from the station) within local range. Outside the local range, analog FM degrades, but with great setup or location you can still get stations hundreds of miles away. For local reception, HD adds little or nothing (or worse). For DX, HD simply doesn't work. So who needs it?
And while the XDR-F1HD generally sounds better on all pure analog, I don't particularly like the automatic muting on super DX stations. On one deep DX station, the Sony sounds very lifeless but a Kenwood KT-8300 sounds punchy, primarily because the Kenwood just lets it all out.