I used to have EAR834P and now own ARC PH3 with DIY modification to SE using infinicap and caddock resistors.
EAR 834P has more gain but less flexible than ARC PH3 due to no good way to load the cartridge. But if your preamp does not have much gain, I wouldn't recommend ARC PH3 with low output(<0.6mV) cartridges, EAR 834P has little more gain. There are component modifications information available to improve EAR 834P sound but still not comparable to stock ARC PH3 sound.
ARC PH3 stock version sounded much better than EAR834P(EAR 834P is not a bad sounding preamp either). I now upgraded some of the components(using Infini caps and Caddock resistors) of my PH3 using SE schematics. Simple as changing a few stock resistors with Caddock or Vishay resistors gave a new life to ARC PH3 and Infini cap upgrade brought the ARC PH3 to another level. NOS tubes always make difference as well.
EAR 834P has more gain but less flexible than ARC PH3 due to no good way to load the cartridge. But if your preamp does not have much gain, I wouldn't recommend ARC PH3 with low output(<0.6mV) cartridges, EAR 834P has little more gain. There are component modifications information available to improve EAR 834P sound but still not comparable to stock ARC PH3 sound.
ARC PH3 stock version sounded much better than EAR834P(EAR 834P is not a bad sounding preamp either). I now upgraded some of the components(using Infini caps and Caddock resistors) of my PH3 using SE schematics. Simple as changing a few stock resistors with Caddock or Vishay resistors gave a new life to ARC PH3 and Infini cap upgrade brought the ARC PH3 to another level. NOS tubes always make difference as well.