ringmod

[Martin Czech]

Now, I tryed to fix the bad carrier suppression with series resistors
for the diodes, yes it improoves a little bit, OTOH the circuit gets
more damping, ie. an additional amplifier is needed to get back to normal
level. Anyway , amplitude has to be quite low in order to have acceptable
distortion and speakthrough. The carrier suppression may be good for
hf use (where the carrier is far away from the signal), but not for
our audio purposes. I is indeed interesting to have the carrier right
in middle of the audio bandwidth (eg. mirror melodies). An electronic
suppression circuit won't help, because in the case of sine as carrier
and modulator the carrier is not masked, the suppresion will make things
worse (pumping the speakthrough), the idea itself is somehow ridicolous.

If you want to ringmodulate a solo instrument, it is essential to have
absolutely no speakthrough during instrument pauses, you can hardly
remove the carrier (not masked by audio) after the recording has been
made, it is always the right way to record a proper signal, not the
"I'll fix it later" method.

How does it look now:

Pro:                         Contra:
Maybe a bit distorted sound  Could be achieved with diode ring rectifier also
                             Expensive audio transformers (3x20DM)
                             carrier speaktrough
                             attenuation -> noise
                             magnetic interference
                             costly MU-metal shielding

Ok, this too much con, I'll take the transformers for another project and
stop this ringmod project.


m.c.