Can I use a step up transformer?

There is some downside to some step up transformers.

They may be susceptible to hum, due to magnetic interference.

Also turning the volume way up (without a step up) may increase the noise level.

Mattmiller,

Ive auditioned the Chinook not long ago. Using a .5mv cart, I couldn't figure out why  I had to crank the volume past 12:00 o'clock for a listenable volume, and I heard zero life coming out of the speakers.

I realized I didn't check to see if the dip switches were set for the high gain 60db setting.

Whilie I'm no audio expert, I can't imagine a  .2mv  difference making that much difference as  your preamp also provides a couple of DB's of gain as well. 

Just another thing to check before throwing in the towel and opening your wallet.

I found the Chinook to be a nice sounding unit. Quieter than my tubed Fosgate, at louder than normal listening levels-past 12:00 o'clock. The Foz however, edged out the Chinook with a more "realistic" presentation. 

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 @thuchan : Could you explain a little:   What do you mean with: """  matching carts and phono stages.. """  and """   should not stop on a basic level. """

Thank's in advance.

Regards and enjoy the music,
R.

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.