Audio Research PH7 versus Manley Steelhead ?

The Manley is superb with a lot of user defined parameters. What I am saying is that it has loading controls wich make it highly configurable.
I only have a much older ARC preamp with a very highly acclaimed phono section, the SP6B.
If you can turn it up beyond 9 O'clock then you need your hearing checked. You can't do much about it evidently but if you had a real low output MC 20+ years ago this was the phono of choice.
So if you really want a revealing phono this could be right up your alley. All this may have no bearing on the PH7's character.

I had the Audio Research PH7 before I purchased the Manley Steelhead. The PH 7 is a fantastic phono amp, especially for the price. Mine was absolutely dead quiet and had all the gain I needed for my Lyra Titan cartridge, which has a very low output.
The Manley has some advantages over the PH7, mainly your ability to really fine tune what the amp is doing. But, I don't find it to be anymore quiet or revealing than the PH7. The benifits of "upgrading" to the Manley are there but, small.

Now I have different phono stage. I used to have the Steelhead and played it side by side witht the PH7. They are both great phono stages. I personally prefer the Steelhead. In addition to its good sound quality, it has tons of adjustment so that you can fine tune the sound of the cartridge to match your system. IMO and in my system, the Steelhead has more detail, better transient attack and dynamics. You can also bypass a linestage by connecting the Steelhead directly to your amp, given your system is highly efficient.

I have Manley Neo Classic 250 mono's with an ARC Pre/Rhea phono. What could I gain by switching out the Rhea for a Steelhead or PH-7. I'm thinking system synergy.

I have heard the PH7, Rhea and Steelhead in my system.

IMO if you don't have any issuesd with the lower than normal MJC gain of 57.5db the ARC PH7 is the best sounding unit of the lot. More organic.

I found the Rhea noisy with LOMC's, the PH7 is not. I found the Steelhead more like SS than tube sounding.