Is a separate phono pre really necessary?

Is the transformer you are using made specifically for this cartridge?  If so, then you may receive little benefit from the additon of a phono state, which in fact will create redundancy with the stage already in the rogue.   Make sure you have the right loading, right cables, right stylus setup, and all before you spend money on a separate phono preamp.  If the Roque's phono section is good, then at most you should be looking to add a headamp, not a full phono preamp.  

If you insist on having a separate preamp, perhaps you should look at Rogue's own, which has variable loading options including a custom setting if I recall correctly.

I’m going to say that the designer of a built-in phono stage has the goal of producing an input that the broadest range of customers will find “pleasant.” The phono stage in my Rogue Sphinx is very pleasant. When I started looking for a separate, I started asking what I wanted to hear. It’s a pretty fine line and so subjective. I ended up happy with the PS Audio Stellar. They occasionally have sales of about 30% off and their trade-ins are generous.

I had the RP-5 and used its internal phono stage with Hana EL cartridge. I was not impressed. I switched to MoFi UltraPhono and it was slightly better but still not what I was looking for (exciting sound but kind of flat in the soundstage department) so I returned it and bought a Sutherland KC Vibe MkIi. Very happy with it. The Hana cartridge calls for >400ohn loading and the Sutherland is perfect at 475. A very notable step up from what Rogue includes in the RP-5  

The Vibe MkII loading options include 100, 200, 475, 1k or 47kOhms. 
It’s quiet, resolving and very natural sounding. Build quality is top notch.  
I wouldn’t hesitate to recommend it. 

You can’t go wrong with Sutherland. I started with his KC vibe, then the 20/20 LPS and then the Duo, each incrementally lowering the noise floor increasing the dynamics. 

@viridian Yeah, you’re probably correct; Dr. Feickert, Linn, SOTA, P8/P10 are all on my wish list. However my current budget precludes a such an upgrade at the moment. But that is why I’m asking about a separate phono stage.

@elliottbnewcombjr Do I like my MM phono stage sound? Not sure. Both sound fine but a bit flat to my ears. Like that AS review you quoted, I’m using the highest gain setting and that could be the issue. Or it could be that I’m running the signal through a SUT and this is loading the cart at the minimum impedance setting. But either way I feel that a separate phono stage might be beneficial. And the extra gain would be welcome as well.

@audphile1 @aj523 @sokogear Thanks for your impressions of Sutherland gear. I’m getting the sense that Sutherland equipment is really good for the price.

@jfuquay "Pleasant"-- that is *exactly* what the RP-5 phono stage sounds/feels to me. It really doesn’t wow me much. And considering I have a pretty damn good cart I feel this might be a limiting part of my system.