On 16 Jun 2008, at 22:31, Michael Iber wrote: Depends weather you want to capture the colouration of the transmitter/ receiver or just the amplifier. I can't work out what the crackles that you typically get on old radio equipment will do to the impulse response, but it may not be possible to capture them. I seem to remember reading that you have to play the signal in at different amplitudes in order to capture the kind of complex non- linear responses you'll get from equipment like this. You should be able to induce the sweep in the coil that makes the pickup work, just put another coil near to the one in the gramophone. You could use something like a telephone pickup coil and play the signal into it. I've no idea what signal strength you'd need, but probably not very much. - Steve