A replica Omega 3320 is a Speedmaster Reduced style automatic chronograph built to mimic the Omega 3320 caliber, which is an ETA 2892-A2 base with a Dubois-Dépraz chronograph module stacked on top. The tell is architecture, not cosmetics. A genuine 3320 pattern runs at 28,800 vibrations per hour with a date quickset, a slim modular stack under 8 mm, and subdials at 3, 6 and 9 o'clock.
What is the Omega 3320 movement?
The Omega 3320 is an automatic chronograph caliber used in Speedmaster Reduced models. It pairs a thin ETA 2892-A2 ébauche with a Dubois-Dépraz chronograph module, so the chronograph parts sit above the base movement instead of inside it. That stacked design keeps the caliber slim and makes the pushers feel light and mechanical.
- Automatic winding with a central rotor
- 28,800 vph (4 Hz), or 8 beats per second
- Roughly 40 to 45 hours of power reserve
- Date window at 3 o'clock with quickset at the first crown position
- Triple subdial layout at 3, 6 and 9 o'clock
Why does the 3320 matter in the replica market?
Thin movements are expensive to copy. A 2892-A2 based caliber leaves room for a slim case, so a convincing 3320 replica has to be thin, light on the wrist, and smooth at the crown. Most factory builds cannot match that profile and substitute a cheaper automatic or a hand-wound chronograph instead.
The giveaways show up in the dial layout and the caseback. If the subdials sit at 12, 6 and 9, or the watch measures 15 mm thick with a deep domed caseback, the movement inside is almost certainly not a 3320 pattern.
How do you identify a good 3320 replica?
Check the case profile
A 3320 build sits around 12 to 13 mm thick before the crystal. Anything noticeably thicker points to a Valjoux 7750 clone, which measures close to 7.9 mm for the movement alone.
Check the subdial layout
Running seconds at 9, chronograph minutes at 3 and elapsed hours at 6 is the classic modular arrangement. A 12-6-9 layout means a 7750 style movement was used and the dial is a cosmetic match only.
Check the beat rate
Hold the watch to your ear or run a timegrapher app. Eight ticks per second with a smooth sweep confirms 28,800 vph. Six ticks per second points to a 21,600 vph hand-wound movement such as the Seagull ST19.
Check the date quickset and crown
Pull the crown to the first position and turn: a 3320 pattern changes the date instantly in one direction. If there is no quickset, or the crown feels gritty through both positions, the movement is not built on a 2892 base.
Check the caseback and rotor
Ask for a movement photo before buying. Look for a signed rotor, Geneva stripes, and a module plate bolted over the base movement with two or three visible screws.
What movements do 3320 replicas usually use?
- Seagull ST19: hand-wound, 21,600 vph, no automatic rotor. Common and inexpensive, but obvious on a caseback check.
- Asia 7750: automatic, 28,800 vph, 12-6-9 subdials. Reliable but thick and the wrong layout.
- 2892 plus chronograph module: closest match. Thin, automatic, correct layout, and the only version worth comparing to the original.
Servicing and long-term ownership
Modular chronographs are serviced in two parts, and many independent watchmakers charge extra or decline the job. Budget for a service every four to six years if the watch runs daily. A timegrapher reading at purchase, showing rate and amplitude, is the best single proof of movement health.
Quick pre-purchase checklist
- Confirm subdials at 3, 6 and 9.
- Measure case thickness and compare to 12 to 13 mm.
- Test the date quickset at crown position one.
- Request a timegrapher photo showing 28,800 vph and stable amplitude.
- Ask for a clear caseback or movement photo.