Choosing the right SUT for my setup

SUT’s do not have universal loading, meaning that just because a SUT is a 1/10 version does not necessarily mean the cartridge will see 470 ohms. Here is an example, my Jensen mc-2rr-L has a 430 ohm impedance that the cartridge will see, while my Rothwell mcx SUT, also 1/10, presents a 100 ohm loading.

The only reason those specific 1:10 SUT’s present 430ohms/100ohms to the cartridge is because they have either a zoebel network or resistive loading that is reducing the load seen by the cartridge from 470ohms.

A 1:10 turns ratio SUT with no loading will present 470ohms to the cartridge.

@dover yes. you are correct, as mathematically it should be 470 ohms. All im saying is do Not assume that is what you are getting. You need to look at the specs...

All Rothwell SUT’s are 100 ohm, the Jensen specifies 430 ohm....it is all there to read on their respective websites.. other makes of SUT’s, who knows what loading they provide, as i don’t own any of them.

So in essence, the Rothwell is used for the likes of my eroica lx and my ortofon quintet blue. Both of which specify a 100 ohm loading. The Jensen is used for my Hana el and my denon 103, both of which specify 400 ohm or greater. If you are not careful you can be applying to large or too small a resistive load to your particular moving coil cartridge, which Will effect its performance and sound.

Boutique SUT’s will provide the user with whatever loading value you desire, However, off the shelf SUT’s have what they have, so you must be careful and do homework. If you believe that cartridge loading does not matter, well then, forget it and be happy.

I like to follow what the manufacturer recommends.

Less loading, numerically higher ohm # will result in a brighter, thinner sound. While more loading, numerically lower ohm# results in a fatter, duller sound with a more pronounced bass.

It’s like the goldilocks and the 3 bears fairy tail, you want the loading just right, like her porridge.

@jctyler among all this discussion, do remember 2 things

1. A good MM stage is paramount if you want good sound. No matter how good is your cart and SUT, the quality of the MM stage will have the highest impact on sound.

2. A good MM stage is expensive. Nearly as expensive as a similarly capable full function MM/MC phono. In fact that is where the bulk of the design and money goes in a phono stage. So it is an expensive affair to dwell into SUT + MM phono.

Moreover choices for pure MM stages are very few in the market.

 If you believe that cartridge loading does not matter, well then, forget it and be happy.

Yes - I have a raft of highly regarded SUT's - and have experimented with a variety of top flight cartridges - from 3-40ohms internal impedance.

What I have found is that the "sound" and quality of the SUT dominates no matter what loading as long as the cartridge is not loaded down too far  ( not less than 10x the impedance ).

In my view far more important is getting the gain right - finding the optimum gain for the phono stage/preamp so as you are not running the volume too low or too high.

Jonathan Carr has written on this forum - loading only really impacts the sound if there are issues with the ensuing phono stage. Loading does not change the "sound" of most modern moving coils. Therefore if a SUT presents 470ohms say to a low impedance cartridge, for example koetsu @ 3ohms, it doesn't really matter.

For those who hear a difference - there is a problem either with the phono stage or arm/cartridge issue.

For what its worth my reference system uses a current sensing MC step up into a tube phono stage, which I prefer to SUT's into same. Doesn't mean you can't get a great result with SUT's.

I don't know which MM phonostage is agnostic to loading. Can you name a few @dover ?