Utter Confusion - SUT Settings

[Boyse6748]

I'm sure there is some advice or expert opinions from you Hi-Fi Guru's on the Forum.

My dilemma, is what settings to use for my current SUT. I have read many articles, and to be honest I'm none the wiser. (Mainly because of lack of knowledge / expertise).

I have included a few photos / information to assist but personally, I just can't get my head round this one.

It's not a case of what SUT, as I've tried a few high end examples without success or perceived difference in sound quality.

Anyway, (and I guess not the populous choice) I have an NJC hand built SUT, purchased on many favourable recommendations.

The SUT has a multitude of setting options, 1:10 / 1:20 and every conceivable resistance setting (see below). However, I am at a loss of which setting is correct or best for the current cartridge, which is a Benz Wood SL. As there appears to be little difference, apart from volume on any chosen setting.

Settings: (Benz SL)

Output Voltage 0.56mV
Source Impedance 0.12 Ohms
Recommended Load >100 Ohms


Amp: McIntosh MA 2275

Phono Stage Sensitivity: 4.4 mV for 2.5V rated output
Input impedance: phono - 47K Ohms, 65pf
High level 22K Ohms

Maximum Input Signal

Phono 90mV
High level, 8V

The rest of the info is in the form of photos, including my current setup. (See below)







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[Boyse6748]

Sorry guys..... failed miserably in getting the photos attached....

Please ignore the above. Useless without the rest of the info.

Peter


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[Firebottle]

Hi Peter, with the healthy 0.56mV output of the Benz I would set the SUT for 1:10, that will load it well and should provide the best sound.

Use for a good while to get the sound quality imprinted on your mind before you think of any changes.
If you use the 1:20 ratio you will be putting a big signal into the phono stage and losing some of the headroom.

Cheers,
Alan

[Boyse6748]

Thanks for that Alan,

Can I ask a further question regarding the Ratio Setting +20dB (1:10)

There are also resistance settings as detailed below. Is there a preferred setting to use based on the information already supplied for the Benz, or does it really make no difference.

Resistance. Ratio Setting.
10k. 82 ohms
20k. 140 ohms
30k. 183 ohms
50k. 242 ohms
75k. 289 ohms
OC. 470 ohms

Many thanks in advance

Peter


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[Ammonite Audio]

The Benz ought to work best into the OC setting (470 ohms with 20dB gain), but often things with SUTs aren't as simple as the theory suggests, so that should be your starting point - determine your favourite setting by listening. You won't harm the cartridge at all, but you should find that as you move down the resistance settings the sound will become progressively more rolled off.

[RothwellAudio]

Can I ask a further question regarding the Ratio Setting +20dB (1:10)

There are also resistance settings as detailed below. Is there a preferred setting to use based on the information already supplied for the Benz, or does it really make no difference.

Resistance. Ratio Setting.
10k. 82 ohms
20k. 140 ohms
30k. 183 ohms
50k. 242 ohms
75k. 289 ohms
OC. 470 ohms

First off, I think one of the specs you have is incorrect. I doubt very much that the coil resistance of your cartidge is 0.12 ohms. It's more likely 12 ohms.

Secondly, I agree that a turns ratio of 1:10 is best for your cartridge.

Thirdly, regarding those figures in the table above (resistance/ratio setting) it looks to me like the "resistance" is the value of a resistive load in parallel with the secondary winding. That resistance will be in parallel with the phonostage's input impedance and will appear to the cartridge as a load with the figure in the second column (bizarrely labelled "ratio setting"). So, given a 1:10 turns ratio, a 47k phonostage and no additional load resistor (ie open circuit, or OC) you get the figures in the last line. If you have a 10k resistor in parallel with the secondary it will also be in parallel with the 47k phonostage and become 8.2k, but will appear as 82 ohms to the cartridge. Those are the figures in the first line.
However, those additional resistors are mostly a waste of time, or at best a hit-and-miss approach to getting anything right (in my opinion). Yes, they may flatten the frequency response by eliminating ringing or compensating for any deficiency in primary inductance but you have no way of knowing that from the figures given.
My advice is to use the 1:10 turns ratio and keep the secondary load at OC (open circuit) to start with. Then try some additional resistance and just listen for any beneficial effect.

BTW, this illustrates how confusing SUTs can be. Say for example you find the 30k resistance setting to sound best, you see that equates to a 183 ohm load on the cartridge and conclude that your cartridge works best into a load of about 180 ohms. No, not necessarily so - the 30k resistance is not acting on the cartridge alone, it's acting on the cartridge and the SUT. It could well be having more effect on the SUT than the cartridge.

[RothwellAudio]

The Benz ought to work best into the OC setting (470 ohms with 20dB gain), but often things with SUTs aren't as simple as the theory suggests...

The implication here seems to be that the theory of step-up transformers is simple and that reality is more complex and into the realms of black art. I beg to differ. The problem is that the theory employed by most audiophiles is an over-simplified one.

[Boyse6748]

Andrew,

Many thanks for that, it's clarified a few confusions on my part.

You are quite correct, internal impedance is 12 ohms not 0.12 ohms.

I've now found the very posh box the Benz was supplied in and the documents for this particular cartridge and there are a few differences to my original supplied figures.

They should have been as detailed below..... and I'm not sure if it will make any difference to your assessment.

Output Voltage: 0.4 mV at 3.54 cm/s
Internal impedance 12 ohms
Recommended loading 100 - 47000 ohm
Optimum tracking force 1.7 - 2.0 grams

Sorry if I caused confusion, but I do really appreciate your response.

BTW! I'm currently trying 1:10 OC at present..... and sounds pretty good.

My confusion in sound quality (perhaps in my head) is the swop from the Whest Two (line stage) phono preamp to the SUT. I assumed the MM phono stage on the McIntosh was the business, but it is a softer sound as you might expect with a valve amp.

I've tried a couple of other SUT's without success, I.e Stevens & Billington and the Audio Note.

Perhaps, it's back to a good phono stage Preamp, unless I can get used to this sound.

Regards

Peter


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[Ammonite Audio]

Actually this is pretty much what I was trying to indicate, although in simpler terms intended to be helpful to the OP. SUTS are far from simple things and sometimes they work beautifully when they should not, in theory, and vice versa. The key is, ultimately, in the listening.


The implication here seems to be that the theory of step-up transformers is simple and that reality is more complex and into the realms of black art. I beg to differ. The problem is that the theory employed by most audiophiles is an over-simplified one.

[RothwellAudio]

Cartridge outputs are sometimes specified at 3.54 cm/s, sometimes specified at 5 cm/s and sometimes "specified" at some unspecified velocity :lol:
Anyway, even at 0.4mV I would say 1:10 is the best ratio.

I'm a bit confused by the rest of the info you give though. Whest Two line stage ? I though Whest only made phonostages. And where does McIntosh fit in? Stevens and Billington transformers are very good in my experience, though I still wouldn't recommend a turns ratio much more than 1:10 if possible. Not sure what ratio you had with your S&B transformer.
My only experience with Audio Note transformers has left me unimpressed.

The best SUT/non-SUT comparison you could try is to use the cartridge straight into the Whest Two phonostage set to MC operation (about 60dB and 100 ohms(ish)) and compare it to the cartridge into the SUT into the Whest set to MM operation (about 40dB and 47k). I'm assuming the Whest can be set for MM and MC but the manual is rather vague. I note with interest however that Whest claim that "during the design stages of the whestTWO we made a crazy decision to incorporate some of the MC REF V ideas, namely its hybrid active/passive RIAA filter stage. Unlike other units at this price point that use the standard ‘input stage-Passive RIAA filter-output stage’ configuration, the whestTWO uses an identical configuration which was borrowed from the MC REF V Mk4 and this can also be found in the PS.30R. This new RIAA configuration...".
New configuration? I was using an active/passive approach to RIAA eq about 20 years ago and it was an idea I nicked from somebody else!

Anyway, when you say you have used other SUTs "without success", could you define success? What is it that you're not getting? And how come you haven't given up on SUTs by now if you had no success with S&B etc.?

[Firebottle]

Perhaps, it's back to a good phono stage Preamp, unless I can get used to this sound.


Just because it is a McIntosh doesn't mean it is necessarily a top notch phono stage. To my eyes, having studied the schematic, it is a very average implementation of a valve phono circuit.

It uses feedback RIAA equalisation whereas passive is generally accepted to be best, plus there are electrolytic bypass capacitors in the signal path. The supply is regulated which is a plus point.

:cool:

[RothwellAudio]

Actually this is pretty much what I was trying to indicate, although in simpler terms intended to be helpful to the OP. SUTS are far from simple things and sometimes they work beautifully when they should not, in theory, and vice versa. The key is, ultimately, in the listening.

My opinon is that if a SUT works beautifully when in theory it should not, there's something wrong with the theory.

[AlfaGTV]

Just because it is a McIntosh doesn't mean it is necessarily a top notch phono stage. To my eyes, having studied the schematic, it is a very average implementation of a valve phono circuit.
...

Don't know about the Macintosh 2275 tube integrated, but a friend of mine uses an E.A.R SUT to up the signal from a ZYX cart into his Macintosh MA-7000. That works beautifully and sounds quite good!
(The Mac does not provide MC suitable amplification)

[Ammonite Audio]

My opinon is that if a SUT works beautifully when in theory it should not, there's something wrong with the theory.

I can do no better than to quote my friend Dave Cawley, although he refers to the pitfalls of measurements rather than theory, as such:

"if it measures well and sounds good, then it is good" : "if it measures badly and sounds bad then it is bad" : "if it measures badly and sounds good, then it could be improved" : "if it measures well but sounds bad then it is bad" © Dave Cawley

[Boyse6748]

I'll try to answer your questions.

I was very happy with the Whest, apart from it's like having an electric fire on your rack (very hot !!).

What I mean about a line stage input, is that the Whest connected to an Aux Input ( CD or CD2) or what ever was free and not into the phono connection, and all parameters were selected via the Whest (as you have already mentioned).

The sound via the Whest is what I can only describe as "in your face", bearing in mind, I have a very unusual setup... Townsend Rock 7... Base Heavy and the the McIntosh MA 2275 which is soft and beautiful.

I have tried to stick with the SUT to try a different sound concept, unfortunately I do not have a Myriad of individuals to tell what is best..... or indeed better.

Perhaps to my detriment, the other SUT's I have managed to loan / borrow, didn't do it for me. if I had limitless amounts of money, I could have tried many others, perhaps with more success.

The WHest can be set exactly as you suggested and in many ways, I sort of miss this sound but I'm trying to persevere with something different.

Somewhat confused to say the least, but I thank you for your excellent advice and suggestions.

Time to sit and think !!!!

Peter



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[Boyse6748]

Alan (Firebottle)

You have broken my heart !!!!

The McIntosh is not a good Amp [emoji853][emoji853][emoji853] with a poor MM phono stage.

Heartbroken.... lol.

We all have our favourites and the Mullard Valves do it for me.


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[RothwellAudio]

I was very happy with the Whest, apart from it's like having an electric fire on your rack (very hot !!).

Perhaps to my detriment, the other SUT's I have managed to loan / borrow, didn't do it for me. if I had limitless amounts of money, I could have tried many others, perhaps with more success.

The WHest can be set exactly as you suggested and in many ways, I sort of miss this sound...

Am I right in thinking you no longer have the Whest? So now you have the McIntosh which is MM only?
So what makes you think it's the SUTs rather than the McIntosh that you don't like?
And what was it about the other SUTs that "didn't do it" for you?

Sorry for all the questions but getting as much info as possible is a big help in diagnosing the problem.
BTW, did the Whest run hotter than the McIntosh?

[RothwellAudio]

I can do no better than to quote my friend Dave Cawley, although he refers to the pitfalls of measurements rather than theory, as such:

"if it measures well and sounds good, then it is good" : "if it measures badly and sounds bad then it is bad" : "if it measures badly and sounds good, then it could be improved" : "if it measures well but sounds bad then it is bad" © Dave Cawley

I quite like that :)
I think I'll paraphrase it:
If the theory says it should sound good and it does sound good, then it is possibly a good theory.
If the theory says it should sound bad and it does sound bad, then it is possibly a good theory.
If the theory says it should sound good but it actually sounds bad, then it is a bad theory.
If the theory says it should sound bad but it actually sounds good, then it is a bad theory.

[Boyse6748]

It's a difficult question to answer, but no longer have the Whest for reasons that are difficult to answer.

I have have two cartridges, the Benz Wood (MC) and a Decca Super Gold (MM).

The West never really did it for the Decca but the MM on the McIntosh really worked... perfectly suited... apart from the requirement of perfectly flat vinyl ( clearance 0.5mm). I'm sure you know what I mean.

I wanted that sometime that I could play both... I.e. Direct into the McIntosh MM or swop to the SUT for the Benz (MC).

Unfortunately, it appears that running two cartridges, is not a viable option.

If I had the choice and a perfect record collection, the Decca would be the choice, but that's not the case.

For those special moments, the Decca via the McIntosh and for the rest....... the Benz via the SUT.

Sorry, but it's a bit of an old fashioned approach.

Trying to get the best of both worlds...... but maybe not possible.

If this confusing.... my apologies.

Peter


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[RothwellAudio]

There is an alternative to using a step-up transformer, and that's to use a headamp. Ok, a bit of self-interest here - I make headamps. Anyway, the headamp I make is called the Headspace and it should give you the sense of slam and impact that maybe the step-up transformers aren't giving you.
http://www.rothwellaudioproducts.co.uk/html/headspace_mc_headamp.html

There's a review here on AoS
http://theartofsound.net/forum/showthread.php?49545-Rothwell-MC-Headamp

Anyway, it's just another option to consider.

[Boyse6748]

Andrew,

Interested, is there any chance of a trial ?...... sorry, but blown so much money on disappointment. Including pure silver interconnects.

You are obviously a bit of an guru and extremely knowledgeable.

Peter

If not , I understand. Let me know.

Peter


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[petrat]

If Andrew is up for that, get him to send his mm phonostage as well, the Simplex ... it's chuffin' good, and very reasonably priced ... like all Rothwell products ime.