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The Pfaffenhofen amplifier office became 1924 put into operation. After extensive renovation, the building is now an excellent and very well-preserved example of the important Bavarian Postal Building School.
In the so-called amplifier hall there used to be several rows of so-called lifting rotary selectors. These “dialers” were devices used to mechanically route incoming telephone calls. In the 1920s it was a technical revolution; these machines ultimately replaced the “woman from the office”, who still had to connect incoming calls manually. The task of the amplifier office was to compensate for cable losses on long lines so that the analog signals running over copper lines could be transported to the next amplifier office - for example in Nuremberg - and the caller could also be heard acoustically there.

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The Verstärkeramt 1924

You can find out more about amplifier technology in Pfaffenhofen here



The executive architect of the Verstärkeramt, Franz Holzhammer, began studying architecture at the Technical University of Munich with Theodor Fischer and Friedrich von Thiersch in 1912 after graduating. From 1914 to 1918 he had to interrupt his studies because of his military service, from which he returned home with a life-threatening wound. After graduating in 1920, he began his professional career as a research assistant at the Munich Post Office. In 1922 he became a government architect and in 1924 a postal building officer.  The Verstärkeramt in Pfaffenhofen was his first independent building in his new role as post office building officer. In 1927 Holzhammer became head of the building construction department of the post office
Regensburg, and from 1930 he worked as the successor to Robert Vorhoelzer, who had moved to the TH Munich, in the same position for the Munich Oberpostdirektion.

In 1932, Holzhammer joined the "Bayerischen Volkspartei" to express his opposition to National Socialism. Contrary to repeated requests to join the NSDAP, Holzhammer, unlike most of his colleagues, never allowed himself to be pressurised into taking this step despite considerable professional disadvantages. He also turned down offers of prominent positions in the NSDAP construction industry, such as Roderich Fick's offer to move to Linz as city planning officer or to join the Reichspost Ministry in Berlin. His promotion to department president, which was actually due in 1940, only took place after the end of the war. Even during the final years of the war, Holzhammer began to rebuild destroyed postal buildings such as the Munich post cheque office on Sonnenstrasse. In 1951, Holzhammer became Vice President of the Munich General Postal Directorate. From 1952, he was also a member of the Bavarian State Architecture Committee.




In his designs, Holzhammer shows himself to be very rooted in his Upper Bavarian homeland and had a high level of empathy for local structural and landscape contexts. At the same time, he also opened himself up to new building, as his late work, for example the telecommunications office on Blutenburgstrasse or the important postal palace on Arnulfstrasse in Munich, impressively illustrates. Particularly noteworthy in the simple buildings are the small, imaginative detailed designs, the well-proportioned play of shapes in window and door designs, soffit depths, cornices, natural stone templates, window shutters, roof overhangs, blacksmithing and plumbing work. The very high state of preservation of the Bavarian postal buildings to this day is evidence of the extremely high quality of craftsmanship.
The Bavarian Postal Building School was the most important manifestation of New Building in Bavaria between 1920 and 1934. Robert Poeverlein and especially Robert Vorhoelzer are considered to be the initiators of this school. Important representatives include Walther Schmidt, Hanna Löv, Franz Holzhammer and Sep Ruf.



With the switch to digital telephony, the repeater offices became increasingly less important and the buildings were empty or were only used for residential purposes. In the 2000s, Deutsche Telekom sold a large number of buildings, including the Pfaffenhofen amplifier office. In 2002, Margarete Antwertinger's daughter, who had an office apartment in the reinforcement office as a postal worker, purchased the building with her family and converted it into a residential and practice building, but then separated from the building again almost ten years later.
In October 2011 we purchased Sleeping Beauty Castle.




We both grew up in parents' homes in which great craftsmanship was passed on to us, but the renovation of a historic building, especially of this size, represented a new dimension for us too. One thing was certain: one day the house should be largely used again Original condition shine. It's like restoring a valuable classic car. The small difference: Despite being renovated in accordance with listed buildings, the Verstärkeramt should meet the latest energy standards and be technically up to date. Norbert, the electrical engineer of the two of us, was faced with an almost impossible task. How do you install a fully automatic ventilation system invisibly and where do network cables go? My mission: "You can install whatever you think is right - you just can't see it." Quite a depressing goal for an enthusiastic technician and inventor. But he managed it.

Chimney flues were converted into pipe ducts, ventilation hoses were hidden in the false floors and cabinet walls in front of supply lines were built by carpenters. Historic cast iron grilles in front of the ventilation outlets are the only thing that remains visible today.

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"Insight into the renovation"



We started in 2012 with the renovation of the former caretaker's apartment on the ground floor. In addition to the handicraft exercises in the first apartment, our goal was, above all, to get to know local craftsmen who we later wanted to win over for the large-scale project. Luck was on our side and we got to know a whole series of friendly and excellent craftsmen and restorers who, to this day, support us in all the tasks that we cannot accomplish ourselves. After more than eight years of renovation of all residential and commercial units with seven bathrooms, five kitchens and the restoration or restoration of countless details based on historical models, the year 2021 is the year in which the house and the gardens (based on a model by the garden architect Willy Lange) largely completely restored.





After the "Deutsche Post" had made quite a racket in the 1960s as part of a general refurbishment of the Amplification Office and had removed a lot of historical fixtures and fittings and replaced them with "chic" 1960s doors, for example, we were faced with the Sherlock Holmes task of finding out what our Amplification Office might have looked like when it was built. Many days in the State Library and the acquisition of a now extensive collection of literature opened up the world of the "Bayerischen Postbauschule" to us and showed us its architectural significance.

The staircase

The attic


But it was above all the luck of the almost archaeological research in the house that fate gave us the opportunity to complete the architectural puzzle:We discovered a forgotten door in the attic that became the pattern for all 27 doors that we had rebuilt. One apartment in the house still had the original shutters, so these could also be reconstructed. In the (stair)well, a restorer helped us to explore the original colors by removing layers so that we could remix the colors.The biggest surprise, however, was the floor of the former offices: the original herringbone parquet was completely unexpectedly revealed under seven (!) layers of flooring. In 1939, a protective covering was laid over the parquet, over which floor coverings - from screed to needle felt to terracotta tiles - were applied for another 70 years. Today the floor, oiled and almost undamaged, shines in a new shine.