That’s more like tape chorus edging into vibrato,I use a chase bliss warped vinyl for similar sounds, all I could really suggest is a couple of oscillators set up so the pitch and volume drift slowly through a set range with an LFO or such like, then filtered to taste.I’d definitely invest in a module to give you an FX loop for pedals though, the Busy Circuits SBG is great and gives you CV control over exp pedal inputs and the new 4ms listen I/O gives you two loops ( although getting the gain levels to suit two pedals/sound sources with one knob is a bit tricky ) or a true stereo I/O,or a loop and aux in.