I run my Benz Wood SL "unloaded" at 47K on my Pass XP15. It sounds the
most open, with airier highs, but admittedly I'd be hard pressed to tell
the difference between 47K and 1000 ohms, maybe even 500 ohms. Seems
the Pass XP15 just isn't that sensitive to loading.
You are correct- when I've pointed this stuff out on other threads, Pass Labs phono section owners respond as you have.
I don't understand this comment... a Manley Steelhead is unstable? The
Steelhead lets you switch loading on the fly and the tonal differences
were easily audible.
If the loading is affecting the sound like that its a good bet that the phono section is sensitive to the resonant peak' RFI as I mentioned earlier. Now I should point out that MM cartridges do behave differently- if you have one of those then loading is critical IME moreso that LOMC. This is partially because MM cartridges do ring at audio frequencies if not critically damped. LOMC cartridges don't ring anywhere near audio frequencies- if you 'ring' them with a square wave the input and output waveforms look the same.
There are IMO/IME four parameters that have to do with phono preamp design:
1) enough gain with low enough noise2) accurate EQ3) resistance to RFI4) good internal stability
It is the last two on the list where many phono sections have problems. If you find for example that you get lots of ticks and pops even with new vinyl, this is a sign that the preamp has troubles with these last two parameters. Needing to have a low resistance load on the cartridge is another (keeping in mind that we are talking about LOMC); if the phono section is set up right 47K as a load will be found to work just fine, assuming that normal low capacitance phono cables are in use.