ETA Caliber C07.XXX

The ETA C07 family of watch movements is based on the ETA 28XX-2 framework (for example calibers 2824-2/2834-2/2836-2) .

This series of movements consists of the following calibers:

• C07.111 – Automatic, synthetic polymer (plastic) parts
• C07.121 – Automatic
• C07.141 – Automatic
• C07.601 – Automatic
• C07.611 – Automatic (Rado R763)
• C07.631 – Automatic
• C07.641 – Automatic
• C07.651 – Automatic, big date
• C07.661 – Automatic, true GMT
• C07.701 – Manual-wind
• C07.811 – Automatic, silicon hairspring

Note: This may not be an exhaustive list of calibers in the C07.XXX family. If you know of a caliber not listed above, please add it to the comments below as this list continues to be updated…

Plastic Parts:

It is common misconception that “C07” in the caliber number means the movement contains plastic parts. The reality is that not all of the C07 calibers are fitted with plastic parts.

The C07.111 is an example of a member of this family which does have an escapement made from a synthetic polymer: The escape wheel and pallet fork.

Some watch enthusiasts are not keen on having plastic in their mechanical timepieces. Does this bother you? Comment below…

No Regulator:

The C07 family is sans regulation device. That means these movements do no have a regulator, nor are they designed to be regulated by the watch owner or a hired watchmaker. The movements are regulated at the factory by lasers.

In ETA’s own words:

“Removing this regulator system is a guarantee of long-term reliability. The calibres C07.xxx and A31.xxx, among others, are not equipped with a regulator system, but adjusted in factory with a highly ingenious laser adjustment system. This laser adjustment of the rate is unique in the world and was developed by ETA and Swatch Group engineers.

The absence of a regulator system ensures better stability of the rate at the end of the barrel’s winding.” –Source

Video about factory regulation:

80 Hours Power Reserve:

The C07 based movements have an increased power reserve over their predecessors. With the typical power reserve being 80 hours, this is where the 80 in Powermatic 80 comes from.

In ETA’s own words:

“The development of a new exclusive barrel architecture optimizing the shaft and spring significantly improve the power reserve of our movements. This patented innovation makes it easy to spend the weekend without recharging your watch on Mondays.” -Source

Video about power reserve:

ETA C07 Tech Sheets PDF:

At this time, there are no official technical communications available for the C07 series of movements. Since ETA stopped selling movements to non-Swatch Group watch brands, the C07 and similar Swatch-only movements seem to be what they are focused on. Although calibers such as the C07 are based on older calibers (2824-2 for example), this new generation of movements are now strictly being used in Swatch Group watches.

For this reason, the new designs and technology are not available to outside brands or the general public – which means the tech sheets are also not available.

So far, nobody has made any such documents available. The lack of a regulation device are the lack of tech sheets have the result of keeping service limited to Swatch Group repair centers – also service revenue. Without tech sheets, there is no official confirmation as to important information like lift angle or amplitude expectations.

Although a C07.XXX caliber is different than an ETA 2824-2 / 2834-2 / 2836-2, you could potentially use the older documentation for some basic understanding about the C07.

Interchangeability:

Despite the C07 family being based on 28XX-2 movements, the direct swap interchangeability has not been confirmed. Be weary of random comments only stating that they are interchangeable without providing proof.

Additional Resources:

• Also read: Powermatic 80