01The shopping list
The plain USB-2 camera adapter (no charge port) works too — but then the battery has to outlast the set. For anything longer than a warm-up hour, get the USB 3 one.
02The chain
Mixer REC OUT (or BOOTH)
→ RCA cable
→ UCA202 line-in
→ USB into the camera adapter
→ Lightning into the phone — charger into the adapter's second port
Prefer the mixer's REC OUT if it has one: it's independent of the master fader, so the house engineer can't ride your recording. No REC OUT? BOOTH out — set its knob once at soundcheck and leave it.
03In Lacquer
Open the record screen — the input chip shows USB Audio CODEC (that's the UCA202). Watch the meters while the mix plays, aim the loudest peaks around the upper third, and hit record. 24-bit capture, live meters, free-space countdown, markers — the whole reliability layer runs the same on Lightning as on the newest iPad.
The UCA202 runs at 48 kHz/16-bit on its input — plenty for a club recording, and Lacquer still writes its master with full headroom discipline. Want 24-bit end to end? Any class-compliant interface (a used Scarlett is ~€60) drops into the same chain.