Can I use a step up transformer?

Thom,
Just on the contrary. When I am using the Chinook with matching step ups this phono stage really starts to blossom.

Regarding matching carts and phono stages if you really want to see what they can deliver you should not stop on a basic level. This matter is not plug & play or just connect two units or  avoid using cables and connections.  Here it starts to become a really exciting adventure. It's a pitty that some audio afficinados never will cross the bridge...but this is the way it is.

Dear Raul,
Basic means using the settings (and ranges) the phono preamp comes with. If you do not stop here but use perfect matching cart/step up combinations thus precisely align the two facing coils you may enter into a different musical experience.

Humand,
matching MCs with the appropriate SUT is not an easy job. If you are using SUTs and they do color the sound, are loosing the low or high end, you definitely have a mismatch. And the result will be like you described.

Working with many phono stages and SUTs I found quite some limitations with 'active' phono stages that 'passive' SUTs overcome.

Dear Nandric,
25 is enough :-)
or?

Dear Raul,
I guess you know dealing with parameters in this matching process that we are facing two coils looking at each other, the one of the cart, the other of the SUT. You need harmonizing both in the best way. You know how to do it Raul as you are working in this special field. You also find good descriptions on the web (e.g. Rothwell). What makes it an experimenting job is the different quality of the coils and the windings. I found that good silver like from Silvercore or Kondo do contribute to a fine sound. Also the Jensen, the Joergen Shoe, some of the Ortofon, the Neumann BV 33, the Hashimoto are of excellent quality. Here again the careful winding and production process are of importance. At my Western Electric 618B SUT pure copper of the 30ies of the last century was used, not the reworked industrialized copper some other design come with. The windings are manually done with enough space.
Despite the frequency band is not as high as with modern designs the sound is overwhelming.

Dear Raul,
Your position is quite a theoretical one: "the best SUT is no SUT".
Of course you always have to deal with compromises.
The weak point in matching is - and you are talking about it too - the phono stage.
When you have experimented with so many MCs and SUTs (and also phono pres) as I did and still do my personal conclusion is you need an excellent phono stage like the EMT JPA 66 or the Boulder 2008 avoiding SUTs. The funny thing is that the quality of the resistors you put on the personal cards in the Boulder is decisive for the sound. Such a small little thing!
You don’t need need investing a big sum on a phono stage when e.g. you go for a Manley Chinnok and use the MM input with appropriate SUTs.
You will be surprised what results you will hear and maybe you will change your opinion quickly.
Manually wiring of transformers is the best way you can do. Of course they are using small machines when doing so. 10 years ago I saw it at DaVinci Audio Labs when Peter Brem was still alive. I think in Japan some high quality producers like Hashimoto use it too.

Investing in SUTs depends on how good is your phono chain and of course the system at all.
Using high efficieny speakers is an add on in my opinion as well as a good reproduction of high but also low frequencies.
Let me state in a somehow provoking way: it makes no sense using SUTs which allow you to harmonise the sound but also push it in the more stable and deep sound producing way when you have a mediocre table and phono stage. 
The good news is: today not so many real audio afficionados stick to a mediocre phono line and system. Good systems deserve using SUTs! The more excellent MCs you are using the more you understand the importance of SUTs. 
I like my MMs too. I am sure I will never convince someone of SUTs who is running MMs most of his listening life.
There might be some exceptions 🤗

"If phonostage gain not enough, investing to higher output cartridge is wiser than to SUT. That's where math easily replaces all the science behind."

- sounds simple, but isn't. Using higher output cartridges you are facing several disadvantages you need to tackle at the matching process.

"What we need for LOMC cartridge is way better active high gain Phonolinepreamp designs and that's all." 

- looks also like a simple solution but isn't too. Otherwise we would have seen designs yet.

I am getting the impression this a lot of  theoretical talk rather having experimented with excellent MCs and perfect matching SUTs. 

A perfect matched SUT is not only able to provide the gain one needs, it also gives a more profound, stable, dynamic and deep sound structure,
in comparison to some Phono pres which provide thin air.

Dear John_Tracy,

what you are describing is an unbelievable but a not rare seen (and heard) phaenomenon. A planned mismatching! I believe you that it sounds fantastic in a way. I did some experiments as well. 

In the end when you put a matching SUT in front of the MM stage you win quite some deep and dynamic soundstage.

 

Dear Halcro,
Regarding your question of tuning the SUT by changing the capacitance I would not recommend doing it. You are creating a somehow high pass filter similar to a loudspeaker X-over.

Dear Raul, I am a little puzzled. You are stating in this thread:
> > "I’m not an expert on SUTs I’m still learning about and what I find out is that the most important subject is to match the SUT ..."

and also:

> > "in my case I experimented for more years than you with the best vintage and today SUTs and with today and vintage top PS, either SS and tube designs.“

Which statement should I follow? Anyway maybe we shouldn’t care so much about these two statements.
Regarding czarivey`s suggestion why not going for higher output MCs? In general he is right, when you are using weak phono stages (are you ? :-) this may help to get more dynamics.If you are running a phono pre with 60db gain you will not go very far with 0,2mV LoMCs – In this case you need going for higher output Mcs. But - and this is the downside: The effective mass is much higher, you have more coil on the cart carrier. Unfortunately this hinders the dynamics!LoMCs are always the spearhead of dynamics but with low output! There is no free lunch.

You are asking me why I said: " facing two coils looking at each other, the one of the cart, the other of the SUT. You need harmonizing both .... "where did you learn this because in your opinion it is " false " too. Raul, this is the basic principle of SUT matching. What should be false here? This is what you are dealing with when you are matching a SUT.You need trying to harmonize the specifications of the coil of the cart with the coil of the SUT. You described it very well when stating it`s not only about impedance matching.
If you do not accept this given fact you should not start dealing with this matter.
Anyway, I remember you asked me why I said some days ago „it is not an easy job matching LoMcs and SUTs“. Hope you understand better now.

Deciding which SUT is appropriate is a matter of personal taste and careful matching!
What were your favourite SUTs and LoMCs when you did your matching experiences?
We all want to learn from your experiences. Don't be shy too...

Wonderful Raul!  I see our exchange was helpful. Now you may have some support for your sales activities. Enjoy the good music 🍻