Are all MI and MM made to drive into 47k ohms?
Just got a new phonostage as I have been wanting to upgrade cartridge, but have been limited to 42dB gain into 47k ohms.
(I could have loaded it, but did not have enough gain for any low output cart.)
I’ll install the Garrott bros MI, but looking ahead to try a lower output cart.
Sort of - it became an informal industry standard a long long time ago...
But if you read the fine print on some of the manuals that came with cartridges back in the day... you will see words such as "recomended load up to 70k"...
What they were trying to say (without actually saying it, as most MM stages were already 47k at that point) - was that optimal performance was achieved with a load other than 47K !!
So yeah - all MM's and MI's are basically specced for a 47K resistive load. - but often, the optimum load can only be determined by measurement and adjustment.... I have the bits & bobs to adjust R load from around 27k to over 100k I mostly find 35k to 70k covers things.... the combination of C and R loading provides a wide range of "voicing" options.
Also worth keeping in mind that whatever the original manufacturers specs were for a MM/MI... all bets are off when you replace the stylus with a non-original one.... and at that point you are on your own for determining what the best loading is.
Typically when someone says "this new needle is allowing me to hear so much more detail" (or other similar...) - it often indicates some peaks and troughs in the frequency response that weren't there before.... and the potential need for load adjustment to get the cartridge back to neutral. On the other hand, many people prefer the new "voicing"...
But if I am going to mess with Voicing, I prefer to do it at the Room/Speaker EQ level, and to know exactly what is happening, rather than roll the dice and take a random EQ, and hope it suits me!