====== IWC 7900 ======
The **790** (and derivatives **7900**, **79000**, and **75000**) family of calibres is a series of midrange [[automatic chronograph]] movements produced by [[IWC]] but based on the [[Valjoux 7750]] series.

===== Details =====
The [[Valjoux 7750]] movement was extremely important to the resurgence of [[IWC]] and the basic design remains in use today. The company has used it for many important innovations since the 1980's, including the [[perpetual calendar]] module developed by Kurt Klaus in [[1985]]. IWC also used the 7750 base for their first [[grande complication]]s: The [[1991]] [[IWC 79091|Cal. 79091]] (which remains in production) and [[1992]] [[IWC 18680|Cal. 18680]] "[[IWC Il Destriero Scafusia|Il Destriero Scafusia]]". Other key innovations are the [[Richard Habring|Habring]] [[IWC 79030|Cal. 79030]] [[Doppelchronograph]] of [[1991]] and [[IWC 76061|Cal. 76061]] [[tourbillon]] of [[1999]].

The first IWC version of the basic [[Valjoux 7750]] movement was the **Cal. 790**, dating to [[1981]]. This was used in the [[Porsche Design]] watches built by IWC through [[1988]] and was essentially stock apart from nickel plating. It lent its name to most movements that followed, with the "79" prefix denoting a 7750 base even today. This was the base upon which [[Kurt Klaus]] designed his [[IWC 7906|Cal. 7906]], which re-established IWC in the Swiss watch industry. This movement was extremely innovative, using fewer components than previous modules, and was the key component in the [[1985]] [[IWC Da Vinci Perpetual Calendar]], a watch that remained in production for more than 30 years.

In the 1990s, IWC used the 7750 as a base for their [[grande complication]] and [[tourbillon]] movements. In [[1990]], IWC announced their first [[grande complication]]: [[IWC 79091|Cal. 79091]] used the 7750 base, adding a [[minute repeater]] to the Klaus [[perpetual calendar]] module. The [[IWC Grande Complication 3770|Grande Complication, Ref. 3770]] remains in production to this day.

{{wst>image_cr|IWC|Fliegeruhr Doppelchronograph|IWC Pilot's Watch Doppelchronograph\\ with **IWC 79230** (ETA 7750 base)}}

Another important chronograph advancement came in [[1991]] with the addition of an affordable [[rattrapante]] mechanism designed by [[Richard Habring]]. [[IWC 79030|Cal. 79030]] was the first mass-produced split-seconds mechanism, and it was as robust and easy to use as Klaus' perpetual calendar. This movement was the basis for the [[IWC Pilot's Watch Doppelchronograph]] and remains in production today as [[IWC 79420|Cal. 79420]]. The perpetual calendar and rattrapante are combined in the [[1995]] [[IWC 79251|Cal. 79251]].

In [[1992]], IWC added a [[tourbillon]] and [[Richard Habring]]'s [[rattrapante]] mechanism to the grande complication, resulting in the famous "[[IWC Il Destriero Scafusia|Il Destriero Scafusia]]". A simpler [[tourbillon]] movement followed in [[1999]], [[IWC 76061|Cal. 76061]].

Many of these movements are [[hand winding]] and include modifications to the basic [[plate]]s of the 7750 base. In [[1995]], IWC further modified the donor movement, moving the [[small seconds]] to 6 00 and replacing much of the movement in the process. [[IWC 76240|Cal. 76240]] is the [[hand winding]] [[rattrapante]] version of this movement, while [[IWC 79240|Cal. 79240]] is the [[automatic]]. The latter movement remains in production as [[IWC 79350|Cal. 79350]] as of [[2019]].

The final novel complication on the 7750 base was [[IWC 79470|Cal. 79470]]. Introduced in [[2004]], this movement includes a novel [[split minutes]] feature on the running minutes hand.

In the 2010's, IWC began moving away from [[ETA]] as a component supplier, gradually replacing the [[IWC 79320]] (based on the [[ETA 7750]]) with the [[IWC 75320]] (based on the very similar [[Sellita]] [[SW300-1]]).

In [[2010]], IWC introduced an [[in-house]] [[flyback]] chronograph movement, [[IWC 89000|the Cal. 89000 family]] and used this instead of the rattrapante in some models. However, this movement proved too costly for the market and the rattrapante [[IWC 79420|Cal. 79420]] used instead. Starting in [[2016]], IWC is replacing [[IWC 75320|Cal. 75320]] with their //[[manufacture]]// [[IWC 69000]] family, which although based on the 7750 architecture, is constructed in-house. This movement is also displacing [[IWC 79350|Cal. 79350]] in new models. It is likely that the Cal. 790 family will be phased out entirely in the coming years.

===== Movement family =====
  * [[IWC 790]] (1981-1988) - Nickel-plated
    * [[IWC 7901]] (1991-1993) - Gold plated, date-only
    * [[IWC 7902]] (1988-1996) - Gold plated
    * [[IWC 7912]] (1995-1996) - [[Etachron]] regulator
    * [[IWC 7922]] (1996-2005) - [[Triovis]] regulator
    * [[IWC 79320]] (2005-2010s) - Nickel plated, 31 jewels
    * [[IWC 75320]] (2010s-present) - [[Sellita]] [[ebauche]], 25 jewels
  * [[IWC 7906]] (1985-1988) - [[Perpetual calendar]] module on steel plate
    * [[IWC 79061]] (1987-1996) - [[Perpetual calendar]] module on brass plate
    * [[IWC 79261]] (1996-present) - [[Triovis]] regulator
  * [[IWC 79091]] (1991-present) - [[IWC Grande Complication 3770|Grande Complication]] [[Perpetual calendar]] and [[minute repeater]]
  * [[IWC 79030]] (1991-1996) - [[Rattrapante]] chronograph
    * [[IWC 79230]] (1996-2012) - [[Triovis]] regulator
    * [[IWC 79420]] (2012-present)
  * [[IWC 18680]] (1992) - "[[IWC Il Destriero Scafusia|Il Destriero Scafusia]]" [[hand-winding]], [[perpetual calendar]], [[minute repeater]], cantilevered [[tourbillon]], split seconds chronograph, 750 components
  * [[IWC 79251]] (1995-2001) - [[perpetual calendar]] and [[rattrapante]]
    * [[IWC 79252]] (2001-2005)
  * [[IWC 76240]] (1995-2005) - [[Hand winding]] [[rattrapante]], [[small seconds]] at 6 00
  * [[IWC 79240]] (1998-2005) - Gold plated, [[Triovis]] regulator, [[small seconds]] at 6 00
    * [[IWC 79340]] (2003) - No small seconds
    * [[IWC 79350]] (2006-present) - Nickel plated
  * [[IWC 76061]] (1999-2004) - [[Hand winding]] [[tourbillon]], [[perpetual calendar]]
  * [[IWC 79470]] (2004-2008) - [[Split minutes]]


{{tag>IWC_calibres Valjoux_7750}}