I'm new to Step Up Transformers

I think you already have stepups in your Zesto.  Most of the MC phonostages I am aware of seem to use SUTs.

Bill

Most tube-based phonostages either have built in step up transformers or expect the buyer to use his own step up transformer to supply enough gain.  The typical tube-based phono stage would need to add more tubes and would run the risk of excessive noise if they tried to supply the needed extra gain without using a step up transformer.

The extra gain needed for low output moving coil cartridges can more easily be supplied by solid state phonostages so they rarely include one in their design.  

I recently purchased a Zesto SUT for an EAT eglo petite tube hybrid MM/MC phono stage. The overall sound from the Rega Aphelion2 cart is fuller with the SUT with MM gain settings compared to without SUT and higher gain on PS. The SUT adds a bit of transformer hum, but cuts the tube hiss. This is not noticeable at normal listening levels, only when I put my ear right next to speakers with nothing playing.

I am also thinking about upgrading my PS, and given the various flavors of noise, I may tend towards a SS PS. No idea what kind yet. 

There are many fine quality tube based phono stages that offer sufficient gain for a LOMC cartridge and do not contain a step up transformer internally. Many of those use a solid state or hybrid gain stage in order to achieve that goal (Manley, probably ARC), but some even do it all with tubes (Atmasphere) and that can be done while preserving a good signal to noise ratio, contrary to what some will say. 

Aesthetix offers all-tube high gain phono stages which I like, but, they have more noise than most tube stages employing only tubes for active amplification.  Among my favorite tube phonostages are those made by Audio Note which require an additional step up transformer, Zanden (built in transformer), and Viva (built in transformer).  

  Thanks for all the responses -  it's great to have access to all the experience out there. 

    My Zestos does have a MC section - it has settings for Low Gain or High Gain. 

My confusion was because a friend with the same phono preamp as mine was telling me a SUT would improve the sound. And others online were saying similar things. 

My Zestos does have a MC section - it has settings for Low Gain or High Gain. 

My confusion was because a friend with the same phono preamp as mine was telling me a SUT would improve the sound. And others online were saying similar things. 

Your Zesto Andros already has SUTs for MC application internally, followed by an internal tube MM phono section. They are Jensen's as used by Lamm, Conrad Johnson, ARC and others.

You would only benefit from using an external SUT if it was higher quality or suits better your cartridge than the internal SUT's in the Zesto. Having installed a Zesto with a variety of top MC's it is a very flexible SUT with multiple loading options. You would have to spend large to get a significant improvement.

The Zesto employs a step up transformer for its MC input.  If you go with a separate step up transformer into the MM input, you will be substituting step up transformers.  Whether you will like an alternative step up transformer is dependent on the quality of the alternative, compatibility with the phono stages, compatibility with your cartridge, and personal preference.

The cost of any alternative step up transformer would also have to factor in the cost of another pair of interconnects.  Some of the better standalone devices can be quite high.  The right choice depends primarily with your chosen cartridge, and some companies even wind them specifically for your cartridge.  If you go that route, you might want to learn a lot more about matching.

The Zesto employs a step up transformer for its MC input.  If you go with a separate step up transformer into the MM input, you will be substituting step up transformers.  Whether you will like an alternative step up transformer is dependent on the quality of the alternative, compatibility with the phono stages, compatibility with your cartridge, and personal preference.

The cost of any alternative step up transformer would also have to factor in the cost of another pair of interconnects.  Some of the better standalone devices can be quite high.  The right choice depends primarily with your chosen cartridge, and some companies even wind them specifically for your cartridge.  If you go that route, you might want to learn a lot more about matching.

The Zesto employs a step up transformer for its MC input.  If you go with a separate step up transformer into the MM input, you will be substituting step up transformers.  Whether you will like an alternative step up transformer is dependent on the quality of the alternative, compatibility with the phono stages, compatibility with your cartridge, and personal preference.

The cost of any alternative step up transformer would also have to factor in the cost of another pair of interconnects.  Some of the better standalone devices can be quite high.  The right choice depends primarily with your chosen cartridge, and some companies even wind them specifically for your cartridge.  If you go that route, you might want to learn a lot more about matching.

Please don't take what I am about to say the wrong way.  Whether an SUT would be to your liking or not is a subjective decision.  It really depends on what distortions your tastes prefer.  Everything has distortion.  Tube phono stages have different and generally higher levels of distortion than is typical for similarly priced solid state units.  Then you add an SUT and two (inlet side and outlet side) interconnects, which adds just a bit more distortion and perhaps noise as well.  Against that the SUT adds greater signal, which can improve signal to noise ratio and of course every SUT has a certain audible signature (yes that is distortion but it can be and often is pleasing to the ear).  So you see the addition of an SUT is not as simple or straight forward as it might seem at first glance.  The only way you can answer your question is to try one and let your own tastes be your guide.  No one can properly advise you beyond what I have suggested here.  This is something you have to do for yourself.  BTW, FWIW, in one of my systems I use a recently acquired Conrad Johnson ART Phono (their latest and greatest tube unit) with most often a Conolidated Silver Wire SUT although the C-J has enough gain to not need an SUT, so depending on cartridge and mood I often opt to forego the SUT.  I also have a Bob's Devices SUT which has a warmer sound and that is used too.  In my other system the phono stage is a PS Audio Stellar all solid state and it is used stand alone.  There is no right or wrong in this matter, no one size fits all circumstances, and in spite strong opinions strongly expressed in this forum and others like it, there is no one best solution.

Great info and advice!  Thanks so much.  

  My vinyl setup is a VPI Scoutmaster II table with a Soundsmith Paua MkII cart. 

I had a MM cart before so this is the first time I've used the Low Gain MC circuit in my Zestos. 

@rmcfee

I am quite familiar with both the Zesto and the Paua.

The Paua needs to see a load of at least 470ohms.

I fiound with my sample the optimum load at 1000 ohms.

I would strongly suggest you try on the moving coil input on the Zesto both the high and low MC input settings and both the 400 ohm and 1000ohm settings to find the best combination.

If you try an external SUT you must ensure that the SUT has a maximum turns ratio of 1:10 to be sure the Paua is loaded at a minimum of 470 ohms.

The Herron phono stage, now out of production but possibly available pre-owned, is another that achieves high gain with an FET based input stage followed by an all tube circuit. It was very highly regarded, one might say venerated, by some who frequent this site, before Herron closed down.

Isn't the Soundsmith Paua a moving iron cartridge? That's the mechanism used by Grado and some others. No SUT required.

I checked and the Paua is indeed a moving iron cartridge like all the others in the Soundsmith line. 

It is moving iron, but it has a .4 Mv output.  

The approach of using a hybrid transistor and tube to supply the needed gain for low output cartridges is to reduce the level of noise from using tubes exclusively.   

The use of a SUT also reduces noise as an issue and adds the sonic signature of a transformer.  If you want tube only amplification (no transistor stage or no SUT) you have far few alternatives.  I mentioned Aesthetix earlier as an all-tube design that sounds good (if a bit noisy); another good sounding example is made by Lector (quiet for an all-tube design).

Yes, it's a moving iron but a very low output, similar to a low output Moving Coil. 

I have two low-output MI cartridges, one of 0.4mV output, which requires an MC input or external SUT, and the other with 1mV output sounds better that way (but could be connected via an MM input and the gain turned way up).

I have three ways of doing it - using the Musical Fidelity NuVista Vinyl and setting the input to MC, using the Quad 24p set to MC (with internal SUTs), or using an external SUT and the Quad set to MM. The last of these sounds the best of the three, so that is what I do.

Atmasphere is also all tube high gain phono, as I mentioned earlier. I’ve owned an MP1 for two decades upgrading along the way. I also owned an Aesthetic Rhea Signature but not the Io. The Rhea is amazing for its remote controlability but was a tad noisy compared to the MP1 when I cranked up the gain. 

Most SUTs, the gain and impedance load are inter-related, some SUTs have optional but not separate settings, like my Fidelity Research FRT-4, but the 4 optional choices are still inter-related, i.e. more gain = lower load. (Load = typical 47,000 ohm phono input divided by the chosen x factor squared), 

SUTs or Phono Stages with separate gain and separage load settings are needed for some cartridges, as the standard ratios don’t fit properly.

Soundsmith says Paua output 0.4mv signal strength, it’s coil is 10 ohm resistance, (very much like my AT33PTGII 0.3mv/10 ohm coil). The strange to me part is they advise a load of greater than 470 ohms?????

industry guidance for MC impedance load says try coil impedance x 10, i.e. try 100 ohms. anybody know why they advise 470 ohms for their 10 ohm coil?

GAIN: they advise a TOTAL gain of 58-64db, keep in mind, that is total, including whatever your MM phono is doing AFTER you pre-boost with a SUT.

i.e. my SUT boosts my AT33PTG 0.3mv x 20.68 x factor (+26db) thus up to 6.20 mv that I then send into my MM Phono input for RIAA EQ and it’s gain. Luckily it does not over-load the MX110z’s phono stage, not sure what it’s limits are.

My SUT has a 10.55x gain option, (+20db), the load is 423 ohms, closest to Soundsmith’s stated 470 ohms.

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

btw, My experience: my SUT does NOT have a sound characteristic of it’s own, it is dead silent, simply and passively boost a too weak signal, allows me to use my existing preferred MX110z Tube MM Phono Stage

is this version yours?

or this earlier version?

In either case, you would use the MC input, and mess with your load options, try 100, try 500, hear any differences, preference, you cannot hurt anything

An MI cartridge with a 10 ohm internal resistance like the Paua and some other soundsmith MIs is not comparable to an LOMC with the same internal R, because LOMI cartridges have a MUCH higher inductance, at least 100X to 1000X higher than the LOMC. The inductance adds to the resistance as frequently goes up. Thus the recommendation for a 470 ohm load as a minimum. Dave Slagle mentioned yet another reason for the recommendation. I run MI cartridges with a 1k ohm load, minimum, usually 47K ohms.

The Zestos model I have is the PS-1 (bottom photo).  I did experiment when I got the cart (2 weeks ago) and found 1000 ohms to be too bright and thin. 

   I believe I ended up at 800 ohms (at least for now) and that setting gave a nice airy high end without it getting thin. 

    Lower settings started getting too dark or dull.  But I am told that carts have a break in period so all that could change.

FWIW, my favorite cartridge is a SoundSmith Hyperion, my SUTs are 10:1, but I also fearlessly interchange a variety of LOMC from Ortofon, AT (the recently introduced AT20 is quite nice), and others.  My philosophy is to try things and listen.  BTW, listen means for a while, not just for a minute or two, maybe at least an hour or more after making a change.  I like to give my ears and mind a chance to adjust to the sound of what I am trying.

I’d say wait through 2-3 listening sessions at least one hour each in length, before making any judgement of a new cartridge, and that’s only if you’re very familiar on a long term basis with the phono stage. And even then, cartridges do change over time from new, probably more so than any other piece of gear.

The Zestos model I have is the PS-1 (bottom photo).  

I believe I ended up at 800 ohms (at least for now) and that setting gave a nice airy high end without it getting thin. 

If you have an 800 ohm loading option on the back panel then you probably have the upgraded version Zestro Andros 1.2

"Id say wait through 2-3 listening sessions at least one hour each in length, before making any judgement of a new cartridge, and that’s only if you’re very familiar on a long term basis with the phono stage. And even then, cartridges do change over time from new, probably more so than any other piece of gear."

Yes!  This excellent advice is worth repeating for emphasis.  Thanks lewm, well said.

My mistake - I definitely have the PS-1.  The setting I settled on was 200 ohm I believe.   

My mistake - I definitely have the PS-1.  The setting I settled on was 200 ohm I believe.   

That's way too low. I would suggest trying at least 400 and check your set up - recheck your VTA, tracking weight etc . The Paua is a very smooth sound, slightly warmer than the more expensive soundsmith's due to the aluminium cantilever. It should not be sounding bright and thin at either 400 or 1000.

Have you tried the two gain settings on the MC input ?

Have the SS Paua and Hyperion MR cartridges.  SS recommends on a loading above 470 ohms and states that below this level upper frequencies will be rolled off.  My phono is adjustable between 25 ohms and 1750 ohms in 25 ohm increments.  After my Paua was rebuilt a year ago it took a while for it to settle (about 15 hours at least) and initially was not happy with the minimal loading settings above 470 provides.  Ultimately, after a little experimentation and a lot of listening, it now performs best at 725 ohms in my system.  My Hyperion MR loads best at 525 ohms. 

I am constantly surprised when others report they hear important differences between two different load resistances, using LOMC or LOMI cartridges, that are numerically very close to each other on a scale of 100 to 47K ohms. Like 725 vs 525 ohms or 800 vs 1000 ohms. I believe the reports because they’re subjective, but I’m surprised anyway; I don’t hear important differences between such values. In fact I think of loading in terms of logarithmic differences. So i might try 100, 1000, maybe 10,000 ohms and then 47K ohms. If the cartridge permits that array of load Rs, I choose one among them but usually the difference in sonics is not dramatic. Atmasphere points out that one is actually loading the phono stage. Maybe my array of phono stages is less sensitive than some others. One thing I would not do is choose a load resistance lower than recommended. Notice that no maker sets an upper limit on load R. None say not to use 47K ohms.

lewn,

I agree with you.  The higher the number the LOWER the loading.  At low value of resistors (meaning a lot of loading) small numerical changes do matter a lot (like 30 ohms and 50 ohms are quite different), but, once one gets above 150 ohms, there already isn't much loading and it should not matter that much.  The only thing that does matter is where RFI is interfering and overloading the phonostage.  In that case, a small amount of loading may be needed to cure that problem and this should not affect the overall sound.  A friend suffered RFI that we traced to the default setting on his phonostage being 100kohms (essentially no loading); when we went with 1kohm loading, the problem went away.

On many cartridges, I prefer a lower level of loading (high value resistor)  than most people choose for their setup.  This delivers a wide open sound.  Jonathan Carr, the designer of Lyra cartridges said that modern MC cartridges do not need additional loading to tame high frequency resonant peaks because those peaks are primarily in the ultrasonic range.  When loading does improve the sound, it is because those ultrasonic peaks can overload phonostages that don't have enough margins for peak levels.  I don't have that issue myself, probably because my phono stage is a tube unit that doesn't have extended ultrasonic frequency response.

I did not try the lower of the gain settings on the MC channel because I assumed that it would be too low.  But I guess it's as easy as flicking a switch to see what happens.  

  I should have thought of that. Duhhh

@rmcfee SUTs require proper care and feeding if you want the best out of them.

Transformers transform impedance. So the output impedance is a function of the turns ratio and the source impedance (the cartridge and cables).

If the SUT is insufficiently loaded (load value too high) it will overshoot (ring), which is saying it will make distortion and be bright. If the load is too much (too low an impedance) the transformer will roll off highs. There is an exact value that is called 'critical damping'.

The cartridge itself doesn't care about the loading until the load is very close to the impedance of the cartridge. So your main concern is making sure the transformer is properly loaded (critically damped) so it will sound right. The correct value (which may be a simple resistance or might be a resistance and capacitance in series) varies with the cartridge and to a smaller extent, the tonearm cable.

This is why I prefer a phono section that has enough gain so I don't have to use an SUT; loading SUTs correctly is tricky and beyond the abilities of most audiophiles. I posted the procedure on a different thread recently.

(To take some of the guess work out of this Jensen Transformers has a pdf file that lists all the cartridges they've encountered for use with their SUTs. Unless your phono section uses a Jensen (which would be a good move as Jensens are some of the best available) that pdf doesn't apply to your situation.)

If you don't use the procedure the result is very much like building a loudspeaker from scratch without knowing anything about speaker design. It will certainly play, but sounding right (being neutral) will be up to chance.

Thanks so much Atmasphere. The Zestos has Jensens (I'm told) in the MC channels. That's great info about SUTs. 

As a person who 50 years ago did build a speaker without knowing anything about crossover design (not speaker design because I blindly followed information contained in a magazine article), I’d say Atmasphere has a point. But if you read the pdf available at Jensen, you see they recommend a rather complex network of R and C to get correct loading. Almost no one actually does that in implementing any of the dozens of different SUTs mentioned on this and the many other threads devoted to SUTs. So what do all those reports mean or how should they be interpreted? With more than a grain of salt, I think.

But if you read the pdf available at Jensen, you see they recommend a rather complex network of R and C to get correct loading. Almost no one actually does that

You are talking about a Nobel network to dampen any ringing in the transformer.

The Zesto Andros has the Nobel network included in their circuit, along with loading options designed specifically for that transformer/zobel. I know this because I installed an in field factory upgrade on a Zesto Andros a few years ago.

The slight complication here is that the Paua is a moving iron not a moving coil so the behaviour will not be at the same as LOMC's.

Soundsmith can advise on which transformers are appropriate.

I am constantly surprised when others report they hear important differences between two different load resistances, using LOMC or LOMI cartridges, that are numerically very close to each other on a scale of 100 to 47K ohms. Like 725 vs 525 ohms or 800 vs 1000 ohms.

You make too many assumptions.

I agree on the MC that if small changes are audible, as Atmasphere has pointed out, it is more likely that the target phono is reacting.

However it is a different electrical model with a MI such as the Soundsmith.

I ran the Paua through 4 phonos in one afternoon, including the Soundsmith phono, and 3 others, both transformer based inputs and solid state and small changes in loading 700-800-900-1000 ohms were quite audible in all 4 phonos. If I recall correctly all 4 phonos sounded best with the same loading, in my case 800 ohms.

Paua owners please be aware that the Paua has undergone electrical changes through its lifetime, the inductance and other design parameters have changed over time so it pays to experiment - or follow the guidelines by Soundsmith.

In my experience with 4 different phono stages. I have always preferred the sound of using an SUT into the MM stage vs the built-in MC stage. Whether the MC stage has built-in step-up transformers or uses SS for gain, the result is always the same for me, SUT into MM always sounds better to my ears. The only caveat is that you must invest in decent phono interconnects for the SUT. 

'I have always preferred the sound of using an SUT into the MM stage vs the built-in MC stage.'

This has generally been my experience too.

My Zestos offers only 2 load settings that are in the range to suit the Paua (minimum recommended setting of 470 ohms):  400 or 1000 ohms.  I have set it at 1000 at the moment but it requires more listening. 

Hello, I don’t think many people understand your question and what your friend is telling you. I personally own 3 preamps that have excellent phonostages. I own 2 high level, very expensive external phonostages that have MM and MC settings. Both external phonostages have Lundahl transformers to step up the signal for MC cartridges.  The point your friend is making, is to try various other Step up Transformers via the MM section of your phonostage. I personally own 7 or 8 SUT’s and have discovered they all have their own unique sound and it takes time to match the perfect SUT with your cartridge. The more options you have, the better the results will be. If you are happy with the built in MC section of your preamp, then enjoy it but if you want to hear things change in sound, just like changing the cartridge affects the sound dramatically, trying different SUT’s can make the sound better or worse as well. I personally am a fan of options.  

The Zesto Andros has the Nobel network included in their circuit, along with loading options designed specifically for that transformer/zobel.

A Zobel network is often used to damp a transformer. But if you change the source impedance, the Zobel network won't be correct.

If you really want it right so the transformer editorializes least, the only way to really know is the procedure at the link I posted earlier.

@chipcalzone : The cables from the SUT into the phono stage should be as short as possible to avoid loading down the transformer secondary. This is something that many users of SUT's are unaware of. My Cotter SUT came with fixed output cables of the proper length. 

@lowtubes : I agree! Different SUT's, like different cartridges, have unique sonic attributes. So experimentation is in order! I have five on hand to try, including a Quicksilver.​​

The Paua is a moving iron cartridge and will work best with a high-gain phono stage - not an SUT.

A Zobel network is often used to damp a transformer. But if you change the source impedance, the Zobel network won't be correct.

If you really want it right so the transformer editorializes least, the only way to really know is the procedure at the link I posted earlier.

Actually the best way is to put your cartridge/transformer on a scope and adjust the zobel to minimise ringing. This I would assume is beyond many here.

I actually used the Zesto/Zobel removed from the phono as a test bed - adjusting the zobel for a 40ohm Denon 103D (New) made very little difference to the sound, virtually inaudible, whereas changing the loading was more audible with that transformer ( Jensen ).

The Paua is a moving iron cartridge and will work best with a high-gain phono stage - not an SUT.

This is not true.

Whilst I am not a fan of SUTs, it comes down to the quality of the various options and more importantly whether the high gain phono vs SUT-MM phono can provide the optimum gain and LOAD.

Each of the options has its plusses and minuses.