if you skip the phono stage, your amp will NOT be loud enough, and if it is, it will sound sucky.
you can go as cheap as a 30 buck phono stage at rat shack i think, or pick up a vintage receiver that has an integrated phono stage, or an el cheapo from amazon, etc. but you need one, wherever you get one.
You will need a source containg a phono stage of some type. This will help, also depending your transport...look at the vintage D-25 (just sold one or would offer), its headphone out is mighty enough to drives those Senns temporarily until you get a suitable pre-amp and setup...
Makes the Senns sings for a fraction of the price VS the cost of a single additional upgrade components, if you are into transportable PCDP rigs..