The topic has come up elsewhere and I thought I had it all sorted in my mind but I'm beginning to questions myself.
The idea was when loading on the primary, the 47K in the phonostage was replaced and the chosen resistor was placed on the primary side linked between the hot & cold on the input phono plug?
So if you wanted a selection say 20R; 40; 100; 220; etc these were placed on a selector switch (rotary) and wired across the H & C of the input phono?
The reason I ask is someone has done this, then measured the load and got readings from the input phono which don't equate to the resistor values they have used. I've checked mine and I don't either.
The Hagerman site suggests if loading on the primary to:
In this instance it would mean a resistor value (for primary loading) of 135.7R to get 40R. Is this because there is 47K in the phonostage rather than 1Meg? Or to achieve 40R on the primary you should in fact use a value of 135R????So let's turn this around. What resistor should you put in parallel with the 47k phonostage to change the loading to a desired value? Note, you can only go lower in value, not higher (negative answer means unrealizable).
Desired Loading:40R , Turns Ratio: 1:18.5, Resistor =19.3 k
You can also put the parallel resistor on the primary side, but then the value is the above divided by the turns ratio squared.
Sorry if this is old hat and stupid, I would just like to understand it.
Best regards