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

@jctyler Selecting the ideal ratio ?:??, is one part of the selection ratio.

SUT's have a sonic signature, I have been demonstrated quite a few models and own a few models as well.

A range from delivering a very rich, Bass Dominant through to a Hue of Rich, with a balance across the frequency range is to presented from different models.

A Head Amp is the Antithesis of the SUT, the models I have been demonstrated and compared to a SUT are Transparent as a comparison, and can be anchored to a certain range of the frequency where it is perceived as being noticeably present, or alternatively balanced across the frequency range.

It is best to learn which areas of the Cart's frequency range is wanted to be exploited or contained.

A 103r with increased richness presented through a SUT with this sonic trait, might create excessive Bass Bloom, if used through a Cabinet Speaker of a Vintage Design.       

I've never understood why someone would choose a SUT except as a temporary solution when going to LOMC from MM. I did this when I first started using LOMC. It would seem that the compromise is more than the benefit. You will have a n extra component and extra cable in the chain. Then there is the sonic signature and questionable loading. 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..

Considering that I don't know everything, I would be grateful for someone to tell me why I am wrong. Thanks

@artemus_5 , You are not wrong at all. I agree totally. One is much better off getting a proper MC phono stage. If you have to do a transformer it is best to install it into the phono stage or preamp. Sowter make beautiful little naked transformers for specific cartridge impedances. Installing them is a breeze. But, you are still better of with a proper MC unit. 

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. You need to read the specs to know what you are getting. Also, load is important as it changes the character or response of cartridge. My Hana el which requires 400 ohm or greater is used with the Jensen, my goldring eroica requires 100 ohms and is used with the Rothwell. It is also better to use a SUT for a low output m/c rather than a preamp with m/c capability. The reason being most preamps rely on j-fets to boost the signal. An SUT transformer is a passive device using only the number of wire windings to transition from lower to higher output. The transformer, if of high quality, should impart nothing to the signal. 

At present when commenting on experiences encountered and the impression made through demonstrations that the New Devices able to offer, I wish the demonstrations had been on my own system, I would feel this method would produce an undoubted assessment and asurity to my comments due to having been able to live with the devices for a period of time.

My HiFi system is being put into storage and is only partially assembled, with CD being the immediate available Source Material.

I have become over the past few months, dependant on visiting homes of friends and experiencing their systems, along with New Devices supplied for demonstration purposes. 

I am a Tube Device user myself and every so often get the chance to listen to very modern designs for Solid State devices..

quite Recently I have been offered demonstrations of Two Phonostages on two separate occasions.

One being the Phasemation E-350 and the other being a model referred to as the 'Avalon', which is a Bespoke Built MC/MM Design by a very accomplished Electronics Engineer with more than 40 years using LP as their main replays and with a selection of their own designs for use with a Vinyl LP Source.

Each of these Phon's during the demonstrations have made an extremely good impression and very memorable and worthy of informing others about.

Even though the two SS Phon's were not compared side by side, the demonstrations were carried out in short succession and the recollected information was enough to produce a assessment that both were very capable and will need a vast jump in design to be seen as easily bettered.

Here is the interesting bit on the day the Phasemation E-350 was demonstrated, there were two Structure A SUT's and a Degauss Device brought along as well,to be used with the E-350 and a Bespoke Built Valve Input/Output Phonostage.

A Pure Silver SUT to work at 100 Ohms and a Copper SUT with a ratio specifically produced to match the in use Miyajima Shilabe were the Structure A  models to be used.

A degauss was carried out between each of the Demonstrations, to keep the trial with fair lore.

The E-350 was Brand New, as said was exemplary in performance delivered as a SS MC Stage.

Next Up was the E-350 with the the Copper SUT. The impression this combination made was immediate and notable, not at any time can I recollect a replay appearing so effortless, it was as if constraints were removed music was supplied with an ease.

When the Silver SUT was added, this had a projection and a room filling presence in all dimensions of the Soundstage. It caught the attention of all attendees and was appraised in good favour. I felt it had a force in the presentation compared to the Copper version, and detecting this was a detractor.

The question was how the E-350 would compare in the MC Section after a few hundred hours of usage.

The Valve Phon' is one I am very familiar with, I have heard from the day it arrived, I have been party to Tube Rolling experiences, and have been demonstrated it in use with a variety of SUT's and Head Amps.

The resident SUT was used first to get a grounding on how it is usually presenting.

Next in use was the Copper SUT, this blew me away, the ease that was noticed in comparison to the SS Phon' was now so bewildering to comprehend, it was in my mind better than any other replay I have heard in this system.

The Silver was quite similar in comparison to the SS when in use, it took on a room filling presence in all dimensions of the Soundstage, where it was different was in the Voluminous perception it conjured, one attendee made the statement 'now they really know what ethereal means'.   

The Copper was the one for me on the day, it just sounded so correct due to the effortless presentation and dare I say it correct matching.

I can advise the use of Phon' with a inbuilt MC Section, there has been good impressions left from experiencing these designs, I own a Valve Hybrid with a built in MC as my second Phon' and it is a keeper.

When the system is up and running once more, I know a Brand of SUT I will be putting to a home trial.

It is not possible for myself to advise to others to avoid the use of a SUT when experiences such as the one encountered above has been achieved.

Ones ears are the best Judge in these matters, in my view any other methods used to evaluate, where a demonstration is not achieved, is theory or fantastical evaluation.