A couple more thoughts, since I was playing around with Pickup machines this morning.
If you use record triggers with Pickup machines, remember that you can hold down the trigger and select which input(s) to use.
So, if you have an installation with an Octatrack, you could (for example) set RLEN to 64, set your pattern to 64 steps, then put a one-shot trigger on step 1 recording from AB and a one-shot trigger on step 33 recording from CD. When a one-shot trigger is hit, it disables all other one-shots on that track. This way, you can decide whether to record from AB or CD simply by rearming the track at the appropriate time. Setting them 32 steps apart gives you more than enough time to do that.
Another thing - any change to Pitch causes Pickup machines to drop out of overdub. You can use that in 2 ways – scenes (see below) or create an LFO shape that is all zero except for one step that is at max. Assign that LFO to Pitch with a very slow rate. Now you can introduce semi-random dropout by simply adjusting the depth and waiting for the LFO to kick it out with a brief pitch change.
Also - remember that Scenes work with Pickup machines. I had a grand time today simply locking Pitch and Direction to a scene and then flipping the slider around while I was playing a loop, then going back into overdub to grab some more audio and then flipping through the scene changes.
You can also use the scene change to introduce the LFO change from above.
Finally - I had a setup with one OT feeding the inputs of a second OT running a pickup machine. The Pickup OT outs were sent to a mixer. I use the pre-fade aux sends on the mixer to dump that output to a pitch shifter/delay box and brought the effected outputs back to the board. I turned down the Pickup OT outs so I only heard the effected signal. Then I messed with changing samples on the 1st OT while it was playing and going into and out of overdub on the Pickup OT and playing with the delay and pitch settings on the FX box. It’s amazing how quickly an hour can go by.
The downside to using Pickup machines is that if you don’t capture the audio while it’s happening, it’s virtually certain that you’ll never be able to exactly recreate it again. The good news is that there are an infinite supply of cool sounds to be discovered.