History of Synthesizer

Synthesizer was a Season of the Drifter quest item used in the historical Gambit Prime and The Reckoning loop. The Drifter presented it after a Gambit Prime task; it combined role Synths into Motes that players wagered in The Reckoning for Gambit Prime armor. Bungie described upgrading the device to enter higher Reckoning tiers. Gambit Prime and The Reckoning were later vaulted, so this is a historical item rather than a current acquisition route.

Sources

• Ishtar Collective — The Drifter: Gambit, in Its Prime — transcript calls it a Synthesizer and describes combining Synths into Motes for The Reckoning.
• Shacknews — How to get a Weak Synthesizer for The Reckoning — Season of the Drifter item, quest acquisition, Mote creation, and tier upgrades.