Phono Preamp. With transformer or fully active

Boy;

Who would have thought SUT’s are so controversial in application. My 2 buddies , that are LP guys, both have fully active with lots of adjustability.
Their systems sound superb, with a Lyra & Purpleheart cartridges 
I think it’s best to start fully active, as it appears
Being a vinyl , newby, 
Then listen and see how it goes

jeff

I might have been a little unclear above when I typed:

I do not consider the use of the rather heavy secondary load in addition to a Zobel as a sonically acceptable solution.

That should read:
I do not consider the use of the rather heavy secondary load in the form of a Zobel as a sonically acceptable solution.

I will add that the load from the Zobel is at higher frequencies only.

Jensen named the parts of the Zobel Rdamp and Cdamp which clearly tells its purpose. I do not know of any phono stage inputs with those parts intentionally in place. It would be interesting to see the response without the Zobel in place to see what it is hiding. I for one do not have a problem with a Low Q 2-5dB peak nearing 200kHz and find that any resistance or network added to tame it does more harm than good.  The 4722 or other vintage mic transformer turned SUT showing the peak in the 20-40kHz range is another situation altogether.

http://www.intactaudio.com/images/SUT%20white%20paper/4722%20vs%20emia.png

dave

Jensen named the parts of the Zobel Rdamp and Cdamp which clearly tells its purpose. I do not know of any phono stage inputs with those parts intentionally in place

I do, it retails for $3500 and has had stellar reviews.

It would be interesting to see the response without the Zobel in place to see what it is hiding.

It supposedly minimises internal ringing in the transformer.
If you simulate the load of the cartridge and run a square wave through the scope you can adjust the zobel to suit. In the afroementioned phono stage I have personally exerimented with altering the zobel to match the internal imedance of the cartridge, it is clearly audible.

The reality is that transformers are non linear in both amplitude and more importantly phase. It is the phase anomalies that kill the music - musical timing and natural harmonics are destroyed by phase anomalies.

In my experience, with an array of moving coil stepup devices to hand including both tube and solid state active, and many much vaunted transformers, is that active devices, for all their faults are more musically compelling.

Play any jazz record where there are changes in tempo within the track and a comparison between a competent active stage and a competent transformer will highlight the transformers destruction of phase and timing. Look at the bottom end in your graphs - its there for all to see.

I do, it retails for $3500 and has had stellar reviews.

Which phono stage is this?  

I agree with you on the phase issues and at some low and high frequency a transformer is going to shift phase and I think that the shift at high frequencies is much more of a concern than at  low.

 musical timing and natural harmonics are destroyed by phase anomalies.

yes....  bell labs found a strong correlation between phase shifts and voice intelligibility.  Higher order odd harmonics are dissonant to begin with, throw in some phase shift and i suspect they get downright ugly.

 Look at the bottom end in your graphs - its there for all to see.

I don't follow.  transformers like all systems have a finite bandwidth and with that they have finite linear phase.  It is much more of a struggle to  get a full 10 octaves of flat phase response out of a transformer than an active circuit so it becomes increasingly important to place the plateau of linear phase in the proper spot.

dave

Which phono stage is this?  

Zesto 1.2 uses Jensen transformers with zobel network in place.

Dover,

This simply means that the Zesto added the network in order to deal with the transformer behavior. That is very different than having a phono with that network at the input and then designing the transformer to work into it. This is an easily solvable chicken or the egg paradox.  My response asking about this was in relation to the quoted exchange below

I do not consider the use of the rather heavy secondary load in addition to a Zobel as a sonically acceptable solution.  

FWIW they *are* designed for that.

I took this to mean that the transformers were designed to work into that specific network which made me question where that network actually exists to require that transformer design to naturally work into it.


You said above:

The reality is that transformers are non linear in both amplitude and more importantly phase. It is the phase anomalies that kill the music - musical timing and natural harmonics are destroyed by phase anomalies.

If the time domain is more important than the amplitude domain then what is the logic of using a network on the secondary that corrects for the amplitude domain at the cost of additional phase shift in the time domain? The link below shows the simulation of a hypothetical transformer with and without a Zobel network to damp ringing at high frequencies.

http://www.intactaudio.com/forum/files/screen_shot_2020_08_02_at_81425_am_139.png

If one choses to use a loading network and likes the sonic results, that is fine. I have always found that sonically, loading is the worst thing you can do to a transformer and using anything more than the absolute minimum required is relying on a band-aid for a preventable injury.

dave

For what it's worth I heard a Zesto vs a NVO phono and the NVO was clearly the superior don't know why there's not much talk about NVO, several yrs ago it was much talked about even on these forums.

If one choses to use a loading network and likes the sonic results, that is fine. I have always found that sonically, loading is the worst thing you can do to a transformer and using anything more than the absolute minimum required is relying on a band-aid for a preventable injury.

I said I could hear a difference altering the zobel network, I did not say I liked the sound. I tend to agree with you on loading - either primary or secondary.

I am in the Jonathan Carr camp where I dont believe loading modern moving coil cartridges impacts the cartridge behaviour. Loading a cartridge impacts the following phono stage behaviour - for example poorly designed solid state phono stages with low overload margins at ultra high frequencies.

In selecting transformers for MC’s in my experience it is better to focus on getting the gain into the optimum position for the ensuing phono stage rather than worry about what load the cartridge sees.

I have still sitting in the cupboard - Altec 4629’s, 4722’s, Jensens, FR’s ( ugh ) and an Ortofon. Have previously heard many others. None of them are neutral, they all have their own idiosyncratic sound.

Even optimising the gain structure, moving coils and step up transformers are like a pot luck dinner - you never know what you are going to get until you try it. And they still have the aforementioned phase anomalies across the audio band.

I heard a Zesto vs a NVO phono and the NVO

Yes I’ve heard both. The Zesto is good value for money, the NVO ( all tube, no transformers ) is very good. My only reservation with the NVO is the use of 20+ tubes in it. If 1 goes noisy what a drama finding it. This would drive me nuts ( and I’m a tube guy ).

@dover if the 22 tubed NVO has too many tubes you should hear the 13 tubed NVO. So very close

Jensen named the parts of the Zobel Rdamp and Cdamp which clearly tells its purpose. I do not know of any phono stage inputs with those parts intentionally in place.

@intactaudio  Our preamps allow that- if we install the transformers internally (an option) then the output of the SUT is set up so the external loading strip on the preamp is loading the output of the transformer. If the transformer is external, obviously the same is true. So any Zobel or simple loading resistor can be installed with ease. I agree as well that if the aberrant behavior is a peak at 200KHz probably best leaving it alone.

An answer to the question about using a SUT vs. using a MC phono stage.
https://917bd498-4992-4ef6-bebe-3f682d04079f.filesusr.com/ugd/7869ac_7637ddd4ac28491fa20e1396de50696...

This discussion is beyond my pay grade.

I do believe that whatever the transformer it is dependent on the performance of the phono amp it is attached too. I have installed Sowter transformers ( they have several units designed for various cartridge impedance) in several phono amps the last one being an ARC PH 3 SE.
All I can say is that it was an easy job and it worked wonderfully well. For best performance the transformer have to be installed within the phono amp. It is also very cost effective. I have also used Sowter's ESL transformers in my Acoustats with great results.
Having said all this I prefer a fully active design. I am particularly enamored by Channel D's new units. They run in current mode and have battery power supplies that isolate the units from the mains. They are the quietest units on the market and not by a small margin.