Can anyone recommend me a crystal oscillator amplifier circuit?
I'm also assuming there would be a problem with harmonics flooding other frequencies, could I filter these out using active bandpass RC filters?
On another note, I recently tried using a passive, variable resistor with a capacitor (RC) filter with an MP3 player and some headphones - I got nothing. If I amplified the output of the filter, would I get any filtered audio out of the headphones (assuming I wasn't filtering out all the sound)?
Your circuit is really crude! This is not the good way to obtain a 1 MHz AM modulated signal.
You should feed 5 VDC to the crystal oscillator, and use a buffer amplifier in which you can apply the audio modulation.
For 1 MHz you can use a common FET amplifier , input to gate and a LC resonant circuit in the drain. Then connect your audio transformer to the DC power supply feeding FET drain. An audio amplifier may be needed to apply a larger audio voltage to the buffer amplifier.
Filtering the 1 MHz output is best done by a coupled LC circuit pass-band filter. RC filters are better suited for audio range.
I can see you do not like to learn the basics. Connecting "some" RC filter to "some" headphones may not work as for a good filter there is good to know the source and load impedances. You apparently have no idea I speak about.
So what are the "basics"? You mentioned I should take account of load and source impedance, are there any things I need to be aware of when it comes to radio circuits?
I would recommend the ARRL Radio Amateur's Handbook, any year issue. There are basics for filters, electronic circuits and also how to design simple transmitters, receivers, modulators you can imagine.
I'll check that out then, thanks!
What the purpose or expected / measured input & output?