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

I have owned a few SS Phon's, a Valve Hybrid Phon, and a Valve Input/Output Phon', I have the two Valve models maintained as keepers.

Additionally whilst on the Phon' Quest, I have experienced through demonstrations, quite a few Phonostages at Bake Off's over the years.

I have heard compared to each other a wide selection of SS Phon's with a 'in built' MC Stage, along with multiple Valve Hybrids and lesser Valve Input/Output.

Not all SS Phon's are equal, I say that with asurity, many topologies are similar and there is a much of a muchness experience encountered, these designs can soon be discovered to not leave too much of a positive impression. Occasionally there are SS Phon's encountered, that are produced using a different topology, and certain models, be it from a Brand or a DIY Build can make a impactful impression and one I would like to experience in my home system. I wouldn't hesitate to try these as a MM > SUT vs the 'in built' MC Stage.

I am yet to discover a Valve Hybrid following a demonstration at a Bake Off, that has made myself want to use it in my home system. The MC Stage does not deliver in a way that I find impressive, and similar designed, but differing models all have a related sonic signature, especially when Jfets are in use. These designs have not conjured up the desire to bypass the Jfet and use the MM > SUT.

My own Hybrid has a different design to a Jfet for the MC Stage, it has a Transformer and has also has been Tube Rolled, I use this most commonly with a SUT, but as it has a multi adjustment function on the MC Stage, I will occasionally use it with a Cart' and produce various settings to see what can be achieved. The Phon' has been given up for extended loan periods and the users have ended up adding a SUT. 

The Valve Input/Output Phon' I use, is a Bespoke Built Design and has developed through a few build guises.  There is an 'earlier prototype version' that has been demonstrated in a Bake Off where Phon's were present up to five figures, it held its own in this Company.  The version I is the latest version with a selection of components in use of my choice. It was also discussed to have an 'in built' MC Stage, but I was reluctant, as I knew the options for it and it seemed limiting to my requirements. I chose to remain MM and have a large selection of SUT's and Head Amp's to experience.

The Valve Input/Output Phon' that I was recently demonstrated the Structure A SUT's through is the referred to 'earlier prototype version' of my own one, hence my keenness to have a home demonstration when up and running once more with the system. 

My experiences of using a SUT and Head Amp in A/B comparisons leads me to suggest that Head Amp's I have used, are best described, as being transparent and the SUT's I have used can be perceived as being Noticeably Rich, Rich, or having a Hue of Richness.

These variations in how a Step Up device presents, allows for a lot of options for a user increase their enjoyment during listening, as their is a option to select a device that will present very closely to their unique tastes and preferred presentation.

Folks, I asked for enlightenment which you have given. So thanks for your responses. Here is what I said from the beginning

The biggest benefit is the cost which can be cheaper than a good phono preamp with enough gain for the LOMC. But even this is not set in stone. I remember the Bent SUT was around $1k some 15 yrs ago..

As I read through all the technical jargon, I believe we are coming from different viewpoints. A DIY POV and a Consumer POV. I am the leter and speaking from my experience and my observations. I believe you are coming to it from theoretical POV. IOW many DIY posters which is fine IF you are that sort. I am a retired builder and chose to build my own house. So I speak as a builder. Many if not most of you are doing the same in building a phono preamp out of different components put together to meet the needs of LOMC. I can applaud that. But not all of us here are DIYer nor have the electronic background to know the various theories involved.

We (I) are/am a consemer. For me its all about getting to the music. I have no desire to own #’s of various components IE audioguy85. But I do have 4K vinyl albums, 1K CD & about 1500 Flac albums. But that is me plus a lot of other audiophiles who are not DIYers in this arena.

But back to the house as an example. I built my own because it would cost me less and I believe I am in the top 2% of my trade. And this is what I said from the beginning. It is cheaper. But only for the DIYer who understands the electronic theories and has worked with the guts of these things, For the typical consumer it is generally NOT cheaper nor better. But maybe you can make it cheaper & maybe better. But I’m still not sold on better. But if you like it, then great. That is what this hobby is about...pleasing our own ears.

So again thanks and I hope you realize that none of what I have said was meant to offend anyone

 

@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