Step Up Transformers….Are they Worth the Trouble?

@lalitk

I concur with comments made that the most direct path, with least material and equipment, can give optimum sound closer to sensation of live music.

One example worked well in my set-up: wiring tonearm cable direct to valve phono board, bypassing RCA plug, socket, and wire, resulted in notably more dynamic sound.

For MC use, there are very satisfied users of Abbas SUT’s, so I just ordered a new valve phono from him with switchable (MM-MC) SUT’s on board ( Abbas Hephaestus RIAA ). It is dual mono design with Mullard Ef37 valves (used in Colossus computer from WW2) and other large Octals. I have one of his EL84 RIAA’s and music sounds highly dynamic, big, and rich, on some LP’s, shockingly real.  (I took out of my system a valve preamp in favour of a TVC for more transparency).  I placed a photo from Abbas of each unit side by side at bottom of my system page.

So I will have flexibility for low output carts (I want to try Mono Miyajima, which sounds wonderful in a friend’s system) with Abbas Hephaestus RIAA, and will soon work out whether I have the same finding as another writer’s comment :

“Best sound of all is my big Grado, which needs no help”.

Similar to Grado, I use Decca MI’s. These cartridges direct into Abbas EL84 RIAA stage sound closest to live music, to my ears, “with no need of help”.

Good luck with your experiment.

I have been an SUT fan for 40+ years,  Even the EAR pre-amps I've used have SUTs built in.  Only my Benz Ruby 3 didn't really like a perfectly matched SUT and would have preferred an head amp instead.  My Dynavectors LOVE SUTs and I now have (purchased at a discount) Zesto Allesso SUT, 40 settings (4 gains/10 impedances).  

@psf4972 Your Statement " One example worked well in my set-up: wiring tonearm cable direct to valve phono board, bypassing RCA plug, socket, and wire, resulted in notably more dynamic sound"

is one I fully get the attraction to, it is a idea discussed with Tonearm Designer / Builder who are friends. Recent experiences had and the impression made strongly suggested this type of Signal Path Interface was worthy of consideration.

I have also been following Covid successful in encouraging a Catt' Technician to bypass the Cart's Lead Out Pins and offer a Continuous Wand Wire from the Cart's Coils or a alternate interface for the Wand Wire Cart' Coils, if convenience of use wins over.

Is it excessive as a method, this depends if one wants Gold Plated Brass Pins as the Signal Path Interface from Cart' Coils / Wand Wire. 

Due to War Zones and Sanctions this design is on hold until the World shows more kindness towards each other. 

In relation to AVC or TVC, the ones I have experienced have added a Richness of Tone, but no where near as a impression certain experienced Valve Pre's have been able to present. 

My AVC is out on loan with other owned VC's to a EE producing a 3 Watt Output Amp', there use of the AVC has been able to substantially alter my assessments made in the past. The 3 Watt Amp' has created a Head Scratching / Chin Rubbing response, I am rethinking everything I have learnt about an Amp's influence on an End Sound.

@lalitk if the Valve Phonostage is selected, with a Valve Input / Output - MM only  Design, you will be adopting  Phon' Type that I use, which has been a Bespoke Build and in the end Voiced to my own preference for the End Sound.

Note: With such a design there is so much more available through Tube Rolling, this simplistic method to create option for the Circuit and Signal Path is for myself extremely attractive.

Fortunately, it took a lot less exposure to Valves as it did SUT's to find my keeper Valves.

Note: Such a suggestion to go Valve > SUT in the assessment of some, will no longer suggest your plan is a Step Backwards, more likely be a suggestion that you are not an Audiophile but just another Stupid OP based on voiced choices being considered/made. 

Great discussion above my pay grade since I'll likely keep using MM carts most of my life now that I stream music about 80% of the time, but I wanted to mention that in May, Steve Gutenberg went down the rabbit hole of getting out some of his vintage SUTs and comparing them to his "reference" Parasound phono stage. The results were interesting to say the least, mirroring some of your experiences. 
HOW TO get the BEST SOUND from MC CARTRIDGES! - YouTube

Problem is that the Parasound does not qualify as a “reference”, certainly not as a high gain phono stage. A classic “straw man” situation. My advice is keep an open mind, experiment as much as you can afford, then do what you like. Verbal arguments are worthless in this case.