I follow the below article... and it has worked out for me in spades... I have copied the text and pasted it here .... I believe Tin Pavacini used to believe the same principles, which is why his phonos are legendary...
Beginning of article:
"Cartridge loading and its efficacy can be a contentious issue among vinylphiles. So, I asked Icon Audio’s designer/owner David Shaw about his decision to hard set 100Ω for his MC option. Was it a philosophical, financial, or design choice? Here is Shaw’s very detailed and informative response:
Hi Anthony
I start my story with a visit to Ortofon’s factories and offices in Denmark some years ago. An amazing company dedicated to phono cartridges, they have tremendous knowledge and expertise. I learned a lot.
Behind closed doors they said two things I have never forgotten.
1. They only really make MM cartridges because the market demands it and MC is superior in just about every way.
2. If you are using MC you will only get the best results with a step up transformer. A $2 chip with 10x gain on the front of MM phono stage is just not the same.
At least part of the reason lies in the fact that the normal loading for an MM cartridge is a resistor, 47,000 Ohms and by convention a passive unchanging load.
Whereas a transformer is reactive load who’s impedance is constantly changing with frequency and amplitude. Therefore, any measurements must be qualified by stating whether it’s a DC measurement or AC and then things like frequency and level come into play. (For example a so called “8 Ohm speaker” (which usually measure 6 Ohms DC) will vary its impedance often between 2 Ohms and 30 Ohms, depending upon how easy it do that frequency).
For example the spec for Ortofon’s superb Cadenza Bronze says:
Recommended Load Impedance: 50 - 200Ω
A pretty wide tolerance don’t you think?
And the £4,000 “Expression” model says “greater than 10 Ohms”, they do not even specify an upper limit! The reason why is that it simply does not matter very much, the impact on the sonics will be small.
So, loading the cartridge with a minimum of 10 Ohms resistor will deliver the correct voltage to the next stage.
But loading the cartridge with a step-up transformer gives coil to coil transfer, then something magical happens! The energy transfer happens with all the micro detail that gives the flavour and emotion of the original recording. It’s “organic”.
So, that is why IMHO (and Ortofon + others) a good quality 10x step-up transformer is all you need. (at about 100 ohms).
I should also add that again IMHO a “pure” tube phono stage is always preferable.
Why? Because when in 1957 RCA/CBS/Decca/HMV agreed on the LP stereo format and agreed on the RIAA EQ as standard, they did this with tubes in mind as transistors were not advanced enough at that time. So, for a high quality accurate reproduction of the RIAA curve with a MM cartridge requires just two medium gain tubes. Doing this with transistors is actually not that easy and requires a lot more complexity. Of course, these days, the use of very high quality, low noise chips is the norm. Technically superb!
But (and this is a very big BUT!), as we know chips contain a huge number of junctions inside so the signal becomes highly processed though possibly hundreds of junctions, micro resistors, micro capacitors. Whereas the simplicity of just two triode valves (plus one for output) gives a much more “open” and “honest” presentation.
This is the basic idea, let me know if you need more.
Regards
David Shaw
Icon Audio (UK) Ltd"
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