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. 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.     

  

Denon made the AU305

6 moons primer

https://6moons.com/audioreviews/stepup/primer.html

think about future changes now:

separate control of gain and impedance is most flexible,

to leave your cables alone:

pass for MM bypass is a nice feature, leave SUT in-line bypassing it's transformer

multiple front selectable inputs is good for multiple arms

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impedance guidance: coil impedance x 10 = _____?

that’s the ’guidance’ impedance you want ’shown’ to your MM phono input. (MM Phono input is typically 47,000, verify yours). then go up/dn from there, it’s just guidance. (nothing wrong, but, frequency response can be effected)

your choices: coil 12 x 10 = 120; coil 14 x 10 = 140, close, so: avg 130. ’guidance.

formula: 47,000 divided by x-factor squared = the impedance that will be shown to the MM Phono input (change 47,000 if yours is different)

now, working backwards to find a desired x factor: 47,000 divided by "what x factor squared?" will be close to 130. 47,000 divided by the goal of 130 = 361 for a desired x factor squared.

x factor 18 sq. = 324. x factor 19 sq. = 361.

Note: it’s inverse: up the x factor thus up the x factor squared, higher number yields LOWER impedance that will be ’shown’

..........................

NOW, that x factor yields what signal strength? enough? overload?

one choice is .25mv x 19 = 4.75mv, allow some loss, say 4.5mv

other .4mv x 19 = 7.6mv, allow some loss, say 7mv.

So, if settings are NOT independant, look for a SUT setting withan x factor of 19 or just a bit lower.

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from an old chart I found:

Denon AU-320 offers too low, or too high xf 10 or xf 36

Denon AU300LC has only xf 10

Fidelity Research FRT-4, 3 inputs + PASS for MM Thruput; offers 4 optional x-factors, one is 18,27 (it’s 30 ohm setting), +25db; another is x factor 20.68 (it’s 10 ohm setting) +26db.

EAR MC4 one of 4 settings is xf 18.

EAR MC3, one of 3 settings is xf 20, +26db

Entre ET 100, 3 inputs + PASS for MM thruput; 3 optional loads

Input impedance: 3, 10 or 40 ohms select, you would use the 10 ohm setting.

Gain:
3 ohm -- 32dB
10 ohm -- 26dB
40 ohm -- 20dB

It’s Tricky.

 

@audioguy85 

 

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.

So you have $$$ tied up into 2 SUT’s rather than one. Yes, Different loadings can be done with the use of resistors. I made loading plugs which did the same. Bent SUT was set up for loading pliugs. But you STILL have an extra component and cable rather than the shortest path.

Also, load is important as it changes the character or response of cartridge

Yes, I understand that. But its NOT a positive thing for the cartridge according to Ralph @ Atmasphere. The loading stiffens the cantilever and is necessary for the preamp so it does not ring like the cheaper ones generally do @ 47K. FWIW I have been running my .LOMC at 47K for about 15 yrs. I have loading plugs to make any value I want. But I chose 47K because it sounds best

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.

That may be true with some but I doubt all of them, especially tubes. I have an SS which I use the 47K loading. So i find your assertion at least questionable. But even if so, you still haven’t dealt the the addition to the signal path. I suspect whatever gains may be made using your idea are then lost with the addition of an extra component and cable.

That said, I appreciate your response. I just disagree mostly. But if you like what you are doing, great. I’d be glad to listen with you.