I'm new to Step Up Transformers

The Zesto Andros has the Nobel network included in their circuit, along with loading options designed specifically for that transformer/zobel.

A Zobel network is often used to damp a transformer. But if you change the source impedance, the Zobel network won't be correct.

If you really want it right so the transformer editorializes least, the only way to really know is the procedure at the link I posted earlier.

@chipcalzone : The cables from the SUT into the phono stage should be as short as possible to avoid loading down the transformer secondary. This is something that many users of SUT's are unaware of. My Cotter SUT came with fixed output cables of the proper length. 

@lowtubes : I agree! Different SUT's, like different cartridges, have unique sonic attributes. So experimentation is in order! I have five on hand to try, including a Quicksilver.​​

The Paua is a moving iron cartridge and will work best with a high-gain phono stage - not an SUT.

A Zobel network is often used to damp a transformer. But if you change the source impedance, the Zobel network won't be correct.

If you really want it right so the transformer editorializes least, the only way to really know is the procedure at the link I posted earlier.

Actually the best way is to put your cartridge/transformer on a scope and adjust the zobel to minimise ringing. This I would assume is beyond many here.

I actually used the Zesto/Zobel removed from the phono as a test bed - adjusting the zobel for a 40ohm Denon 103D (New) made very little difference to the sound, virtually inaudible, whereas changing the loading was more audible with that transformer ( Jensen ).