Choosing the right SUT for my setup



I’ve decided to add a SUT to my setup. My MC carts are a Denon 103R (14 ohms/0.25mV) and an Audio Technica AT-OC9XSL (12 ohms/.4mV). I’m trying to decide between two used SUTs: the Denon AU-300LC and the Denon AU-320, both having a 1:10 ratio. Would loading ideal gain for the 103R and the OC9 be best achieved thru a using a calculator and installing a resistor that can be switched for carts or testing with a trimpot then installing resistor? I’ve also seen writeups where the OC9 is put on a 1:12 SUT and 1:20 for the 103R; from the boards experience is that pushing overload, or its in a good spot?

jctyler

@artemus_5  I don't usually buy into a Consumer Product anymore, most of what I own is produced for me as a unique item. This as a purchase method does not  discount me from being a Consumer, it is that the products are not purchased as are the usual methods and are not items from a mass produced assembly.

The most important part of this hobby for me today is the social side, I carry out more social arranged listening now, the idea of shutting the door of a room and listening in isolation is a rare happening. The benefits for myself through being social in this hobby  is that a selection of the arranged social events are with a theme, and this allows for new musical encounters, and sometimes with unfamiliar equipment that can be very impressive.

 Through being demonstrated various devices over time, it is inevitable that a device might be stumbled on that makes a big impression. It is also inevitable that such a device might catapult itself into being an item of interest.

If such an item of interest is able to be home trialed, then all the better for broadening the experience, it does not detract from the enjoyment of the music being replayed, it usually reinforces the reason why this hobby was to be come a mainstay. What usually occurs through encountering unfamiliar equipment,  is that in certain cases a new flavour is supplied to the music that is already much enjoyed, and a preference for how a music is to be replayed can be expanded on .

A fixed, rigid viewpoint does not allow for these encounters to occur, an open mind is best to produce experiences that are the most fruitful, an 'inquisitive nature' and 'what if' approach is a valuable attitude and a route to make new discoveries.

I am not thinking of myself as an audiophile in the basic description anymore, I see this type in my mind and older practices used by myself are more solitary and insular in the activities around music replays.

I today view myself as more of a collaborator. I function very contented within a Group of likeminded enthusiasts who like myself, have a history within HiFi of experiencing a large variety of HiFi equipment and a love of recorded music replays as a shared interest. It is nice to know individuals who are all proud of still owning a Vinyl LP that is 40ish years owned and still proud to play it. These same individuals are as at home with CD and Streaming, so there is plenty to keep a Group on their toes.   

Greetings

To OP

I didn’t read what type of phono preamp you are presently using. If you only have a MM phono stage, then yes you will need a SUT. 
The cartridge’s that you list can easily be used with most MC phono stages. Any MC cartridge above 0.2 mv should work fine with most MC phono stages, with a gain of 60 to 65 db.

‘If you just want to experiment with SUT, go for it but be warned that picking out the wrong one is throwing money away. Also picking out the wrong one will give you lots of HUM for you to listen to.

‘I recommend that you read the article that is located in the “Vinylengine website” titled Step Ups and MC Cartridge’s. It is very well written and wealth of information. It was written in 2006 but still applies today. It has all the info you need to calculate the correct SUT for your cartridge.

The bottom line is that going  for a dedicated MC phono stage is the best way to go.

Just for reference I have 3 dedicated MC phono preamps and 2 MM phono stages. I also have a Denon AU-S1 SUT that I use with and only with my Denon DL-S1 cartridge. The DL-S1 has an output of 0.15 mv. Can be hard to drive do to it being below 0.2 mv.

Joe Nies

@jctyler 

I must also apologize for highjacking your thread. I didn't mean to do so. But maybe you have both sides of the issue. Choose one and enjoy

Neither is necessarily best, it is what your own ears decide. My ears prefer the SUT routed to the MM section of a Tubed phono preamp. Any hum encountered when using a SUT can sometimes be caused from using inferior wires. You should be using a phono specific cable, preferably a shielded one. However, hum can be eliminated by turning, repositioning , or relocating the SUT.

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.