  Pion electroproduction off the proton is analyzed in a new framework based on
a general parametrization of transition amplitudes, including constraints from
gauge invariance and threshold behavior. Data with energies $1.13~{\rm
GeV}<W<1.6~{\rm GeV}$ and $Q^2$ below $6~{\rm GeV}^2$ are included. The model
is an extension of the latest J\"ulich-Bonn solution incorporating constraints
from pion-induced and photoproduction data. Performing large scale fits
($\sim10^5$ data) we find a set of solutions with $\chi^2_{\rm dof}=1.69-1.81$
which allows us to assess the systematic uncertainty of the approach.
