Applying an effect to an instrument that is also in a track

I would like to apply an effect to an instrument that will be used in a track as well. I've already tried to add it to the channel and track like normal:

inst = pd.sound.instrument.new()
inst:addVoice(synth)

channel = pd.sound.channel.new(inst)

But I get a "synths may only be in one instrument or channel at a time" error. Is there a workaround?

Thanks in advance!