What is a simple synth that you could plug into a guitar amp that could create backing track drones while you play along? Instead of having to use one of these pedals :
Electro Harmonix Freeze Pedal: An Honest Review - YouTube
Electro-Harmonix Freeze Sound Retainer | Reverb Demo Video - YouTube
Create INFINITE FREEZE DRONES on Helix and HX Stomp - STEP BY STEP GUIDE EHX FREEZE - YouTube
Electro-Harmonix Freeze Pedal Review - Guitar Space
Infinite sustain pedal for practicing scales over drones: EHX Freeze and alternatives | Page 2 | The Gear Page
Electro Harmonix Freeze Sound Retainer sustain pedaal | Bax Music