MC phono stage without transformer?

Tpsonic, the problem is that a lot of really musical cartridges have low output- 0.2mV to 0.3mV. Many tube preamps have troubles with cartridges this low.

One of the better SUTs we auditioned was made by Jensen, outstanding in the world of transformers with decades of experience.

We found that loading was paramount to reducing the artifact from the transformers. Jensen was well aware of the issues and has a loading chart for their devices along with a lot of popular cartridges.

Despite having the loading optimized, you could always hear the insertion of the SUT. Admittedly, it was more on the subtle side, but over a period of weeks and months you got to be more and more aware of it. Switching back to running direct (our preamps are designed for low output MC), there was an immediately noticeable improvement in air around the instruments, a greater sense of delicacy and obviously improved detail.

I suspect that having a direct-coupled output on both the preamp and the amps helps us hear extra detail, but one thing is for sure- it was the sort of thing that anyone in the room could easily hear and it was very repeatable.

Dear Viper and friends: I posted somewhere:

+++++ " The SUT is an old patch for bad SS phonopreamps designs and for the inherent limitations on tube phonopreamps for handle low output MC cartridges. It is a " cheap solution to a complex problem ".

There is no synergy between low output MC cartridges and tube phono preamps and less than that there is no synergy between SUT's and quality music sound reproduction.
The problem is not on your phono preamp the problem is in that you buy the wrong cartridge for your phono preamp. Your phono preamp is for high output MC cartridges and MM cartridges. " +++++

and here this link: http://forum.audiogon.com/cgi-bin/fr.pl?eanlg&1138829438&openflup&41&4#41

The SUT subject has many " sides " to analize/comment.IMHO to understand why people like Atmasphere, I and some other people speak in that way it is a must to undertstand what happen ( which hard " road/process " most pass the cartridge signal ) for the cartridge signal goes to the amplifier/speakers with out noise/distortions/colorations and almost intact and truer to the recording, these means with almost no degradation at all!!!.

Through my music and audio life I learn many many things like what to do and what not to do ( on many subjects ), I learn too through the professional magazines like TAS, STPHILE, etc, etc and I learn from them for what they say but for what they don’t say too! I always try to learn ( every single day and from any where. ) on what is my passion: music and home music reproduction.

I already state many times the paramount importance in the Phonolinepreamp ( that only a few people agree with ) I have to understand why is so important? What is the main work of that item? What happen inside it? What does not must happen inside it? And many other questions.

What happen with that tiny/fragile cartridge signal ( LOMC or any other ) when goes inside a Phono and line stage?, first the signal has to be amplified ( in some cases , very low output ) almost 10,000 times before could be amplified for the system’s amplifier, 10,000 times!!!

This Phonolinepreamp work is a “ tour du force “ because that amplification level must be with out any signal contamination of every kind: RFI, EMI, noises, distortions, colorations, etc, etc, how to do it with so tiny/fragile signal level? Well this is the first challenge that the designer has to understand and try to handle it.
How to do it with almost no degradation on the cartridge signal? How to do it making that the cartridge signal be always truer to the recording? How to do it with a minimum signal “ manipulation/handle” ? well these are our design challenge.

Second the cartridge signal must pass a very critical stage where that signal can suffer a heavy degradation if you don’t take care, I can say extremely care: inverse RIAA curve equalization where the signal ( in a simple explanation way ) must have around 20 db of boost on the bass octaves and 20db lowering in the high frequencies, after this process the signal have a flat frequency response that will be amplified at the line stage and final in the amplifiers.
This is a lot more easy to say that to do it with accuracy. What I mean with accuracy? Well that the phono stage RIAA curve be a mimic ( inverse one ) of the RIAA curve with which the recording was made, any deviation in the phono stage RIAA curve makes that the reproduced “ sound “ be far away from the recording and what we want is to be near and truer to the recording!!!

Because the RIAA eq. is not linear but a curve any single deviation at any single frequency “ disturb/degrade/ have an effect on almost three music octaves, this kind of RIAA eq. deviations makes and create distortions and colorations in the cartridge signal, distortions and colorations that are not on the recording: so the target here is to conserve intact that tiny/fragile signal with out no RIAA eq. deviations.
That’s why I always say that a good Phono stage must be ( at least ) at no more than 0.05db deviation from 20hz to 20Khz.
My Phonolinepreamp is calibrated to achieve a RIAA deviation of no more than 0.015db, this figure could make a difference? no doubt about. I’m not a measurements item lover but at the RIAA eq. accuracy is the name of the game other things equal.

As you can see the cartridge signal can/could suffer a heavy degradation through the phono and line stages, more than in other analog links. So we have to take care of that cartridge signal in a way that can/could suffer a minimum degradation.

We need that the cartridge signal pass for the SHORTEST “ road “ before the amplifier/speakers/room final stages, because in any single stage ( phono stage, line stage, phono stage connectors, line stage connectors, IC phono to line stages cable, etc, etc ) the signal suffer a different type level degradations that alter the original signal and that puts a lot of “ veils “ between the signal and you ( your ears music signal perception ), in any single stage/link we are “ loosing “ part of the signal that we can’t recovery ever and at the same time we are adding distortions/colorations that was not on the original signal.

We take in count all these subjects in the design that’s why my system unit has the phono stage and the line stage integrated on the same unit ( we don’t degrade the cartridge signal through a lot of additional stages: phono stage connectors, input line stage connectors, IC cable, etc, etc, SUT, SUT connectors, SUT IC, ) .

We don’t only take care of the Phono stage design but we take care ( with the same “ passion “ ) to the line stage design because the cartridge signal always must pass through it and here the signal could suffer additional degradation.
As you can see ( again ) to have a well designed Phonolinepreamp is a complex task. There are many other critical subjects on the design, please let me explain only one more:

It is not only important to have 0.015 db on RIAA deviation but most important is to maintain it over any playing condition!!!!: all electronic parts ( transistors/valve/resistors/capacitors ) change its performances with temperature changes, this means that if we don’t care about that RIAA deviation can change with changes in the item running temperature ( high distortions and colorations ).

Now, to introduce a SUT ( internal/external ) put several additional " veils " between you and the reproduced cartridge signal, those " veils " from different kind and with differente range level of distortions/colorations/omissions/additions/etc/etc.

So, why too many people use SUT's?, well it is a cheap solution, it is more easy to design with SUT that to make a high gain active Phonolinepreamp design ( SS or tube one ): a lot lot easy!!!!

But that: lot lot easy!! means too: a lot lot degraded sound against the very high quality performance of a well active high gain Phonolinepreamp, no doubt about!!!

The very SAD subject on this " history " is ( like in this thread ) that many un-informed ( non-knowhow ) people not only accept the SUT's but support it when the SUT's goes against the quality sound reproduction in any audio system and not only this but that acceptance send a very clear/precise " message " to the Phono Stage designers/builders: EVERYONE IS SATISFIED WITH THE POOR SUT's PERFORMANCE SO WE DON'T HAVE TO TAKE CARE ABOUT TO IMPROVE THE QUALITY PERFORMANCE OF OUR PRODUCTS !!!!, because you have to know that all those SUT's builders/designers know what they produce.

Of course that to achieve a high quality sound reproduction through a non SUT based design has a price ( $$$$ ) to pay, no doubt about and of course that you have to choose what do you want, what performance level do you want, what quality sound reproduction level do you want and of course too that not all the people have the money or the same high level performance priorities and that's is another reason why exist the SUTs.

Regards and enjoy the music.
raul.

I will just say that there are several active head amps and phono stages that can handle LOMC at around 0.25 mv so both SUT and head amp are viable. The impact of very small changes in loading of a good SUT (Bent) was very audible in one very revealing analog rig that I've heard and clearly but not very audible in my (at the time moderately revealing) rig. So if you go SUT, make sure you can easily adjust loading (again like the Bent) and then incrementally zero in on the right load. You may need to run resistors in parallel and changes as small as 1 or 2 ohms are audible.

If you have a good MM stage, then I would consider an active gain stage if you can afford it; if you are starting from scratch and the phono stage (internal or external) you are considering has an MC option, whether it is SUT or active gain based, implementation and matching are probably more important than the actual technology. THere was a recent article in S'phile, by MF I think, that discussed the SUT/cart matching issues in depth and he concluded that the "best" SUT depends on which cart it is being used with. And also there are the cabling issues; the "effective" length of the interconnect, if you have an outboard SUT, is "multiplied" by the step up ratio (I'm using the term multiplied loosely; I don't really understand the technical issues involved). With an on-board SUT, IC length is essentially zero, so that drops out of the equation.

if there was a universally applicable answer, then only one of the two technologies would persist. As usual, it depends. With the v. low voltages involved, as Raul indicated, the what "it depends" on becomes very complicated. And esp so with an SUT where the cart/SUT needs to be looked at as a unit.

FWIW, I now use a ZYX ss mc phono/active gain stage into the line stage of a either a tube integrated or a tube pre and OTL amp, with a ZYX cart LOMC cart. I also had v good results from a ZYX head amp into the MM stage of my tube pre; better than the MC stage, but then the MC stage did not have user adjustable loading at all, let along the ability to vary it in very small increments. The ZYX phono and gain stages are not adjustable in any way, but they make magic iwth the ZYX carts. The bass in particular is stunningly good.

Raul, I agree with your post in principal but sut's are an affordable solution to a complex problem. not all of us can throw $12k at our phono pre and a properly implemented sut whether active or not can and does provide an accurate, clean and musical signal. For most systems its a matter of choosing your preferred distortion.(id love to hear your pre amp)

Rccc- cost is of course an issue for most of us, but IIRC, Raul's product (which I have not heard) is as he calls it a "phonolinepreamp" or as most of us call it, a full function pre-amp. If its $12k, that's not out of line for v good similar products like VAC Ren, Atma-sphere MP-1, Asthetix, etc. BAT VK-51 line stage plus standalone phono stage is more than that. Manley Steelhead phonostage is $7k alone w/o a line stage. And that does not consider the bleeding edge products like Audio-note. High end SUTs seem to start at just under $1K, but you still need a phono stage and line stage (integrated or stand-alone) plus cabling and PCs to go with them.

An SUT can be a cost effective solution for sure; perhaps Raul's choice of words "cheap solution for complex problem" could have been different (inexpensive or economical solution to complex problem), but let's not forget that he is not a native English speaker.

Analog rigs are transducers that have very complex mechanical, electrical, and audio issues, so its not surprising that there is "more than one way to skin the cat" and of course many listener's have different priorities and so may favor one design solution over another. For many of us, cost is also a factor. and every design is a compromise in some way. So the "right solution" varies from individual to individual and from rig to rig. Viva la difference!!!