When is it time to consider adding a SUT?

Two words come to mind: distance and irritation

Dear @billstevenson : I never leave a question with out give an answer.

You said: "  your open answers. "

For me, in audio, exist no open answers but many times are very elaborated answers because in audio each link depends of all and each other links in the audio chain.

An open answer as : yes or not or an  item model means nothing with out an explanation of the " open " answer.

The other side is that all audio human beens  understand audio subjects in different way and that's why dialogue/discussion sometimes is useless for every one.

You posted:

 """    My solid state reference has been a Lehmann Silver Cube  """

in the same post with your " open questions " and that tell me that is probable that you and me can talk on different audio subjects.

With all respect to Lehmann and its owners and to you I think you have a very low reference line. I'm not saying is a bad reference only that could be not a real reference to discuss your questions. It's curious that been a phono stage the manufacturer specs did not shows the RIAA deviation level. Why ? could be an interesting question for you and its owners.

SC is a SS design that use in its first gain stage a microphone amp chip and in the second gain stage another chip by BB and and an output buffer with FETs. Lehmann had its own way of thinking about. I never heard it in my system but through different system.

When I talk about SS phonolinepreamp SS designs certainly I'm refereing to a different kind of designs/performance where my only reference is live music.


Regards and enjoy the MUSIC not DISTORTIONS,
R.

Thank you for your answer although I must confess that it is not entirely clear to me what you are saying in all particulars. So I will not respond to the parts where I do not fully comprehend your answer. We can agree that everyone of us has unique experiences and that it is difficult to share points of view based on different experiences, references, environments and so on. Nevertheless it can be worthwhile to discuss matters of mutual interest even if our diverse backgrounds prevent full accord. So, I don't agree that it is useless to try.

Although I am an engineer, I am not an electrical engineer and am not qualified to discuss circuit designs or the relative merits of same. I think we can agree that faithfulness to a spcification such as, but not limited to, the RIAA equalization curve would be sine qua non to achieving reasonable sound reproduction. You argue to strive for reproduced sound that is comparable to live music. Although we can agree that this is a noble goal, I suspect we differ on weather it is possible to do so in any practical sense. This is an interesting subject, but far removed from the subject of phono preamps. Nevertheless, since you raise the point, let me comment briefly.

The difficulty is the acoustic environment that a reproduction system is called upon to operate in. It is not and cannot be identical with the one where the recording was made, unless both the live and the recorded result are both listened to in the same space. Although that can be done and has been done, it is not what most of us do in our recorded music lives. As such, it is better to acquiesce to the reality that for most music reproduction the playback environment will be different from the original performance environment. That fact makes using the standard of live performance less practical than perhaps we would wish it to be in an ideal sense. In it's place we substitute various components and compare one vs. the other. Not ideal, but that is what we do, or at least that is what I do. With that said, in my listening room I have a piano and a set of drums and a lot of hand percussion instruments. So I do try to seek the holy grail, but alas my piano sounds different from an identical one played elsewhere, and even something as simple as a triangle or a ride cymbal sounds quite different in my home as compared to that same triangle or cymbal played out in performance. Too, a piano sounds different if heard at the instrument playing it on stage vs. hearing it played by someone else while standing anywhere out in the audience section. Cymbals, triangles, snare drums and on and on all sound different at various locations because of the reflections, reverberations, and so on imposed by the environment.

So, back to phono stages. I listen to music that I am familiar with; first with one phono stage, and then with the other. Most of the time, using good recordings, it is possible to hear a difference. Usually I prefer one over the other. And usually I prefer the sound of tubes although noise can intrude. This is never more true than with LOMC cartridges, even very expensive ones. And when this noise intrudes I have found that a good step-up transformer is the best solution. Now, I think the conversation is back where we began. I like green, you like yellow. Is the conversation useless?

Dear @billstevenson : No it's not. For the contrary it's a good music/audio conversation.

@lewm posted: "  Raul and I are more often than not on opposite sides of controversies like this one . " and you posted:

"  it can be worthwhile to discuss matters of mutual interest even if our diverse backgrounds prevent full accord .... "

I think that mature audiophiles as us in reality are more in agreements than against each to other even when we do not have a full accord. As a fact what makes  an audio conversation a good one is precesily when exist no full accord because it's when the different " sides " of the whole conversation works as a lesson for any one of us and is the only way to grow up. Obviously that the people involved in that conversation must have the attitude to always learn.
Some times in a hot audio conversation and when I think that the other gentleman has no " reason " on the subject time latter ( days, months or even years after. ) I take in count that that gentleman was rigth and me wrong.

""" 
we can agree that faithfulness to a spcification such as, but not limited to, the RIAA equalization curve would be sine qua non to achieving reasonable sound reproduction """

not only agree but for me this is the first target and characteristic between a preamplifier/headamp or the like and a phono stage where when we read or some one talks about phono stage the name really comes because that audio item has the inverse RIAA eq. and not because its gain level or something else.

You mentioned the second and third targets in a phono stage where both depends in between: gain/amp levels and noise levels.
So we are talking the same audio language, good.

"  You argue to strive for reproduced sound that is comparable to live music "

well, I said that my reference as your is live MUSIC. What means that reference for me?  to know in precise way how and which is the kind of sound that produce the normal music instruments and to know it not only in different kind of enviroments ( orchestra halls, open stages, amplified or not, etc, etc. ) but at near field too with single instruments or blended..

I agree in your comments about and could add that even two same Steinway piano models in the same venue sounds different because can be that have different build material chords ( vintage. ) or something with the piano differences in the build wood or paint and the like. Exist no two same year Stradivarious with exactly the same sound.
Again, in agree that is imposible to mimic live MUSIC through a home audio system.

Now, I posted several times that my audio system main target is to be truer to the recording or at least nearest to.

For my effort trying to approach and have success in that target I need that at every single link in the audio system chain be faithfulness developing the lowest every kind of distortions ( obviously each audio link item must be a good design and with excellent quality design execution. ).

With those premises in mind and knowing in deep both technologies: tubes and SS, by first hand whole experiences I decided to left behind the tube alternative because can't fulfill my main system target. I's just imposible to do it for the tube alternative. As any alterative tubes has trade-offs but against the target are severe trade-offs insuperable limitations to achieve the  targets where SS is way nearer to acomplish it.

I don't listen MUSIC in my system only because I'm a MUSIC lover and I just like it. NO I like to listen MUSIC in my system the way SHOULD be and this " SHOULD be " means truer/nearest to the recording. This is way different to listen only because I like it what I hear even if is wrong.

We are in agreement of the critical importance role of the inverse RIAA eq in a phono stage and to be truer to the recording this inverse phono stage RIAA eq. MUST MIMIC the RIAA curve ( inverse. ) used during the recording.

What means " mimic ": exactly that, with no frequency deviations in between. Well, because its inherent tube limitations this alternative can't fulfill that premise and the SS alternative can do it in a nearest way. Yes, accuracy is always the name of the game here. Ideal could be: cero tolerance that per sé is imposible to achieve.

Of course that I'm using full SS electronics. I don't want to talk in deep about my system but only to give you a precise example where tubes can't do it and my phonolinepreamp does:


https://photos.google.com/share/AF1QipPJLuDhIxhHGsjv2ZABr3TIpxMewVor1Pz33vhLoiISsURJmmnxUQB9cuwNnpog...

that kind of performance is near " perfect " ( nothing is. ) not only because the frequency deviation levels are lower than 0.015db ! but because both channels performs almost exactly.
Btw, you can check through Stereophile electronics measurements ( every kind of. ) and always both channels ( every kind of audio item. ) measures different, way different!

Well, that's me about MUSIC and audio.

Thank's for your answer.

Regards and enjoy the MUSIC not distortions,
R.

I now have my Benz lps installed and about 12 hours on the cartridge. Changing the impedance settings from 100 to 1000 provide noticeable  changes in tonal balance. I settled on 500 as at 1000 there was some noticeable ringing on certain vocal tracks. 

I don't know if there are dynamics missing as the entire presentation is miles ahead of my previous Shelter 501 Mk II.     Ill give it another dozen hours and assess again.