Absolutely agree with your statement that there is no "correct" loading value and it needs to be done by ear.
Not sure I agree with your comment how mfrs arrive at their 'recommended" value ... the specs for my Benz LP merely say "500 ohm to 47K ohm"!
Yes and this is where it gets interesting ... and why I asked my question.
IMO, there is an optimal load for any cart - it is not logical that this value should change when a SUT is suddenly introduced in front of a MM phono stage (ss or valve) instead of using a pre-pre amp (aka ' headamp').
Why a mfr might suggest 2 different values, to me is because of the way a SUT modifies the default 47K loading which most MM phono stages have. As I'm sure you know, when a SUT sits between the cart and the MM phono stage, the cart 'sees' 47K / sq of the turns ratio. So with a 10:1 turns ratio, the load becomes 470 ohms ... with a 20:1 turns ratio, the load becomes 118 ohms.
This, IMO, is the weakness of SUTs.
A mate of mine who also owns a Benz LP was using it with his very expensive, very nice-sounding, US-made MM/MC valve phono stage. With the 0.28mV output of the benz, he obviously had to plug the phono cable into the MC input - which had an in-built 10:1 SUT ... which meant he was loading his LP with only 470 ohms.
He knew I loaded mine at 3K3 and asked me how he could increase
his loading. I lent him a JFET-based headamp that I own (which has a parallel pair of input RCAs, designed to take 'loaded' plugs), which he used with the MM input ... and was delighted with the better sound from his Benz LP.
Regards,
Andy
He was delighted