La Grande Classique de Longines


ETA 255.511

Factory Spec. 10 SPY

Thermocompensated: Dual Oscillator (32 kHz + 262 kHz)

User Adjustable: Yes


There appears to be relatively little data available on the dual oscillator movement in this watch, however I have read that ETA used crystals with frequencies ranging from 262 kHz to 2 MHz as the auxiliary oscillators. Assuming that is true, then, given that this is a slim-line, dress watch with a small battery, I'd assume that the auxiliary oscillator in this case is of the 262 kHz persusion.

Some details of this watch are missing as it is not well documented and has yet to undergo comprehensive tests.

Parent Company Swatch Group
Brand Longines
Model Series La Grande Classique de Longines
Model Name Lyre
Model Number 173
Case Number 7176
Serial Number 25047570
Approx. Date of Manufacture from 1985
Calibre (mvt maker) 255.511
Calibre (brand) L 173.4
Factory SPY 10
TC Appproach Dual Oscillator & Count Adjustment
Frequency (XO 1) 32 kHz
Frequency (XO 2) 262 kHz
Rate Adjustment User
Major Inhibition Period unknown
Minor Inhibition Period unknown
Power Disposable Cell
Cell Number SR916SW
Case Back Press (requires case press for closing)
Water Resistance Not stated
Features 3-hand, no numeral dial
  Date (not perpetual)
Timing Results Basic data  &  Further details
Images Photos - Large File Sizes!
Documents Technical details