RE: Futaba receivers
Futaba 617's work fine with 6 Volt (5 cell NiCds and NiMhs) battery inputs. Since a full charged 5 cell pack is up around 7 Volts the receivers work fine at that voltage. Have been using 617's with Hitec digital and analog servos for quite a while, along with 6 Volt packs and have had no problems what so ever. Regulating voltage down to 5 volts for 617's is not necessary and you would also then lose the advantages of pushing 6 volts into the servos. That is, if the servos are rated for 6 volts... This info comes directly from Futaba. "All Futaba systems are designed to operate on either 4.8 volts (NiCD 4 cells) or 6 volts (Alkaline 4 cells OR NiCD 5 cells), except certain servos which are specifically labeled for use at one voltage or the other only. Some manufacturer's systems are not designed for and do not operate well on 6 volt, but most Futaba equipment handles the increased power input and provides increased performance, speed and torque."