The Neuman NU67 is a high quality German studio microphone of 1970 vintage,
which has come from the Macquarie University Speech Research Centre. It
became obsolete in 1985 when the valves for it became difficult to obtain.
It has one EF86 valve in the microphone proper and a separate power supply
with a balanced line transformer unit. The microphone required a new valve
every 6 months, or when the noise figure exceeded specifications. The microphone
can be desk mounted or boom mounted. The sensitivity pattern can be switched
to cardioid, figure 8, or omni directional. It has a web suspension to
reduce any conducted noise. It was replaced by an transistorised AKG studio
microphone which cost around $3000 in 1985.
power supply circuit