requires high electromechanical and optomechanical cooperativities [@safavi-naeini_design_2010; @hill_coherent_2012], which have yet to be achieved together in a single device. Alternatives to high cooperativity have been explored in other optomechanical systems; in particular, feedback damping has been experimentally shown to ease cooperativity requirements in individual platforms [@cohadon_cooling_1999; @arcizet_high-sensitivity_2006; @poggio_feedback_2007; @genes_ground-state_2008; @wilson_measurement-based_2015; @rossi_enhancing_2017; @rossi_measurement-based_2018]. But quantum electro-optic conversion studies have to date focused on reaching the threshold $N_{\mathrm{add}} < 1$, at which point arbitrarily low efficiency can be tolerated using quantum repeater concepts that herald the creation of entanglement probabilistically [@duan_long_2001].

In this work, we explore electro-optic conversion in an alternative feedforward framework where quantum tasks could be performed even if thermal-mechanical noise yields $N_{\mathrm{add}} > 1$, provided threshold efficiencies are reached. We demonstrate an unprecedented conversion efficiency of $47 \pm 1\%$ in a micromechanical device operated at $T<100~\mathrm{mK}$, and implement a feedforward protocol that exploits noise correlations between the two converter output ports to reduce added noise to $N_\mathrm{add} = 38~\mathrm{photons}$. These figures of merit represent significant technical progress relative to the $8\%$ efficiency and 1500 photons of added noise achieved in a prototype system operated at 4 K [@andrews_bidirectional_2014]. Furthermore, while we focus on electro-optic converters here, our feedforward protocol 