Comparative investigations of superconducting properties at 4.2 and 2 Kelvi
n are presented for NbTi and NbTiTa wires manufactured by identical heat tr
eatments. Three NbTiTa alloys with 12.4; 14.0 and 20.4 wt % Ta have been st
udied in this work. Single and double stacked wires with filament diameter
from 20 to 3 mu m are under the consideration. An attempt to optimize criti
cal current density for high field application is described.