Thanks Phil and Owain for you replies.

** Lotsa cassette decks have dedicated mic inputs ( often on the front)
using 1/4 inch jacks - these normally work well with internal battery
powered electret mics.

My external mic is an electret condenser with an AA battery and it
has a 1/4 inch jack which I have plugged into an adaptor to make it
3.5mm to fit into the tape recorders 3.5mm dedicated mic input.

The RCA line inputs on the back do not have adequate gain or the low self
noise needed for use with mics - that is unless you don't mind yelling.

My mic's specs say:
impedance 600 ohms
sensitivity - 74 dB (0 db = 1 V/microbar, 1 KHz)
frequency response 20 - 18,000 Hz
polar pattern hemispherical

According to the tape recorder's specs, it's input sensitivity and impedance
is... "external microphone: 4 mV, 600 ohms"


David