Hello friends! once again please excuse the very green question.

I am trying to build a tromello style amplitude mod effect in pd.

I know how to do this on a modular analog synth:

just plug an LFO into your amp.

How would you acomplish this in PD? as far as I can tell you can't controll * with an OSC~ but maybe I just don't know what I"m doing.

You can control [*~] with an [osc~]. This would give you tremolo. When you write to a delayline with [delwrite~] and use [vd~] to read it out you can also drive the [vd~] object with an [osc~] to obtain vibrato.