Devised, researched
 and written
  Peter King Smith BSc

                                                         The mid-1960s, German-built multi-track tape recorder with FM/AM/SW radio

History of the Schaub-Lorenz Music Center (BBG) 

Herbert Hamann, an ex-Graetz-SEL employee who worked in Product Preparation with Wolfgang Gerwien, recalls fragments of the birth, rise and demise of the Schaub-Lorenz Music Center, and reveals some of the problems faced by the engineers and others involved in the making of the BBG tape machine.

This short account of the history of the BBG is based on Konzept für Thema BBG, a talk given in German at the GFGF radio club's AGM in Erfurt, Germany, on 17 May 2008, by Herbert Hamann. 

The transcript of this talk was gifted to the author of this website at the end of the proceedings, which included a display of two well-known music centers (5001 and 6000 models), and a very unusual music center that was specially adapted with a stereoscopic slide-viewer (see Unusual uses).


Sander & Janzen
In 1959, Graetz KG [1] acquired Sander & Janzen (aka Saja), a company with factories in Berlin and Duderstadt which made tape recorders, dictating machines and drive motors for turntables. In 1960, following the acquisition, Graetz decided to transfer Saja's tape-recorder development and production teams to their factory in Altena, Westphalia. 

The Graetz factory, Altena, Westphalia, Germany
Photo from company bulletin Graetz Nachrichten

Saja's material unusable
Much of the material that the Saja personnel took with them to Altena from Berlin and Duderstadt turned out to be unusable. This was because Saja had failed to make proper technical or production drawings beforehand. Consequently, in order to enable further tape-recorder production, new drawings had to be made again from scratch, in Altena.

Plagued by production problems
From the start, Graetz was plagued by Saja production problems which took an enormous amount of time to sort out. One ex-Saja employee, the former boss at Saja's plant in Duderstadt, who apparently knew everything about the tape-recording machines, and who could have helped solve the production problems, was unfortunately not available to them. 

Saja production terminated
The Saja personnel who transferred to Graetz, Altena struggled to sort out the chaos themselves, but never did. One day, production came to a halt, permanently.  

Standard Elektrik Lorenz acquires Graetz
Two years later, in 1961, Graetz KG was bought by Standard Elektrik Lorenz AG (SEL), and the BBG unit known as 'Division VI' became part of 'SEL's 'consumer electronics division known as Schaub-Lorenz. For commercial reasons, the BBG became known as the 'Schaub-Lorenz Music Center'.  


Engineers flee to West Berlin
Meanwhile, in 1960, four engineers working in Eastern Germany, namely, Friedrich Knochenhauer, Günter Löffler, Kurt Senglaub and Hans-Georg Fuchs, quit their jobs in East Germany, crossed over to West Berlin with their families, and ended up in a refugee camp seeking asylum from the Communist regime. 

Engineers with tape-recorder experience
The four engineers had all previously worked together in Eastern Germany for Funkwerk, a company making tape recorders in the Köpenick district of East Berlin. Funkwerk was a subsidiary of the measuring-instrument company Messgerätewerk Zwönitz, headquartered in Zwönitz, a town nestled in the Erz Mountains south of Chemnitz. These engineers, together with their families, settled in Altena, Westphalia, where they began working for Graetz KG as design and development engineers, assigned to the music-center (BBG) project. 

Music Center (BBG) project begins
In that same year, 1960, the main design and development of the Schaub-Lorenz Music Center took place at Graetz in Altena, a project that became known internally as the 'Breitbandgerät' [2]. The four new engineers from Eastern Germany, together with Siegfried Apitz [3a], the youngest member of the BBG team, plus the Saja personnel, had the necessary tape-recording expertise to initiate Graetz's new tape-recorder project. 

Aim of the project
According to two members of the Product Preparation department, Herbert Hamann and Wolfgang Gerwien, whose job it was to ensure that production-line personnel knew how to assemble the machine, it was "not the aim of the BBG team to make a professional machine to the highest standards". 

One of the engineers, Friedrich Knochenhauer, was appointed departmental manager to head up the BBG's design and development team. He is described as "an exemplary individual", and was known to his colleagues as "KN".  

Hans-Georg Fuchs was given the responsibility for the mechanical construction of the BBG (music center). Unfortunately, he died in a car accident in 1963/64 during the developmental phase, and would never see the final production version of the music center that he helped to develop. 


Four models
The team of design and development engineers at Graetz/SEL devised four versions of their music center, but only three models ever made it to production. These were: 

1. The 5001 table model with 126 tracks. 

2. The 5005 upright model with a simple built-in record player, and a mixer unit (5012) as an accessory. 

3. A central chassis, type 6000, complete with a 110v power-supply unit, a stereo version with 81 tracks, for the US export market. This model was called the "STEREO tape recorder 6000" and was supplied with a manual for connecting the chassis to a valve amplifier/vacuum-tube amplifier, and indicated that a 110v to 220v transformer would be required for use in Europe, and that further accessories were available. 

A special fourth version was conceived by the team for use by the Police for recording day-to-day work situations and police proceedings. Of prime importance was that this particular tape recorder would have needed a significantly greater recording capacity. This version was never made, and was just a pipe dream. 

A plethora of patents
In the midst of all the technical problems, Friedrich Knochenhauer managed to dictate a plethora of patents to his secretary, Mrs Rapp, after hours [3], in the administrative wing of the Development block. 


Complex manufacturing process
Reminiscent of the troubles encountered earlier with the transition of the Saga tape-recorder production to Graetz, Altena, the production of the BBG also suffered major problems arising from the coordination of all the various manufacturing processes.

In addition, there was very little tolerance in the mechanical and electrical components, which only facilitated the occurrence of manufacturing faults [4]. Consequently, many components had to modified. 

BBG more a 'pilot' series'
Unlike the mass production of television and radio sets, the design and manufacture of the BBG was more like a 'pilot series'. The BBG was so complex that it would have been impossible to make thousands of identical copies. The team discovered that it was not possible to produce a reliable device. 

Main problems
The main problems were with the reed relays and the wide tape. As regards the tape, the BBG team were pioneering a completely unique, high-spec material for use in tape recorders; the tape had to be very robust and yet very elastic. Moreover, the tape they needed had to be 100mm wide and 150 metres long. A specification requiring such a wide tape had never been produced before anywhere. These tape requirements created a massive headache for the BBG team.    

Choosing the material for the wide tape 
At first the team experimented with tapes made from polyvinylchloride (PVC), but they did not work because the tape transport from one spool to the other was insufficiently smooth. The team then tried using a polyester tape. This proved a time-consuming and very costly process. 

Propulsion magnets
Incidentally, the propulsion magnets (Ger: Zugmagnete) were also a bit of a problem. Their function is to propel small levers forward inside a solenoid, to actuate the tape drum's brake, for example. These magnets were known to make a scratching sound that was far from stimulating, especially when you were trying to enjoy an evening of stimulating music. 

Manufacturing plants
The BBG's tape-recorder unit was assembled in SEL's factory in Kaufbeuren, 91 kms south west of Munich, and in Rastatt [5]. The machines that were used to make the metal components for the BBG were made by Mitsubishi. All the rest of the music center was made and assembled in Altena, and later at the FS factory in Bochum, 22 km west of Dortmund. 


Production terminated
After just two years, production of the BBG was terminated, due in part to the introduction of the compact cassette (compact audio cassette tape) by the Philips company in 1963, who offered a simpler and cheaper method of recording on two pairs of stereo tracks. 

Unsold stock of music centers
SEL sold off the remaining factory stock of finished music centers cheaply, but this was not quite the end of the music-center story [6].

In Germany, an electroacoustics company in the Ruhr region purchased a batch of these left-over music centers, as did some department stores, and used them for years to provide background music in public places [7].

At the time, they were seen as a good alternative to renting music products such as Muzak, 3M or Reditune, from the established background-music suppliers. By the time their recordings were made available to customers, music-center owners had already recorded and were already playing the latest pop-music numbers to their own customers.  


What became of the team?
In 1968, Standard Elektrik Lorenz AG began transferring their Production and Preparation department and their Design and Development department from Altena to Pforzheim [8], where their sales division had already been for some time [ed. ± 1965].  The remaining members of the music-center's development team left SEL to take up new positions in various other companies. 

Friedrich Knochenhauer
He moved to a company in Munich called Grünwald, a firm that had made the drive motors for the BBG. In 1973/74, Friedrich Knochenhauer suffered two successive heart attacks while driving to work in his car, and tragically died in the car in the presence of his two daughters, aged 47. [9] 

Gunter Löffler
He worked for a time with a company making radios called Labor, but later became a teacher in a school in Gummersbach. 

Kurt Senglaub [10a]
He went to Telefunken in Ulm.  

Siegfried Apitz [10c]

Wolfgang Gerwien and Herbert Hamann
They did not want to move with the Product and Preparation department from Altena to Pforzheim and so decided to go their own separate ways, although only geographically. 

Wolfgang Gerwien went to Munich to MBB, while Herbert Hamann went to work for a small technical office specialising in electroacoustics, which was active in department stores. 

End of document 

Translated from the German with the help of Hans van Straalen and adapted by the website's author. A copy of Herbert Hamann's original German document can be found in the 'Archive' section.


1. Company historyFor further details on the history of the Graetz company, see the Graetz company history

2. Breitband
A term Breitband has caused confusion in the past when translated into English. The tape should not be translated as 'broadband' in English as that is a telecommunications term that refers to signal bandwidth, something completely different from the designation 'wide tape' (preferred), or 'wide band' (see Schaub manuals). 

3.  PatentsThe industriousness and diligence of Friedrich Knochenhauer and Mrs Rapp are reflected in the tables in the three Main Patents (see chapter on Patents), which summarise the key components of the music center invention that were protected by patents he took out. 

4. Quality controlThis was almost certainly due to inadequate quality control procedures and inadequate feedback to the assembly line. This is described in 'Top 4 Faults, No. 1'

5. Manufacturing sitesRastatt was not mentioned as one of the manufacturing sites in Herbert Hamann's Erfurt document. 

6. Fate of other Music Center stock:See (i) In search of new business, and(ii) The 6000 stereo chassis. 

7. Copyright The department stores may have technically been in breach of copyright legislation, which makes it illegal to play recorded music in public or in a public place without paying royalties to the recording companies concerned. The same applies to those hotels and pubs that used them. Whether they did or not, is purely academic now. 

8. Move to PforzheimA reliable source recently communicated the date to the author as being 1967. 

9. DatesThe original date of Friedrich Knochenhauer's death is shown in the Erfurt document as 1963/64. This is not. This would have meant that FK never saw the launch of the BBG in 1965, and could never have left SEL for a company in Munich after production of the BBG was terminated. After I had pointed out this discrepancy to Herbert Hamann, he manually altered the date of the car accident in his document from 1963/64 to 1973/74. In fact, Kurt Senglaub has recently confirmed the exact date with me, but his final age is still unknown.  

10. The inventors: (a) I recently discovered that Kurt Senglaub was deliberately excluded from being mentioned in the patents as one of the co-inventors. For further details, see my interview with Kurt Senglaub.

(b) Another co-inventor of the BBG, again not mentioned in the 'Erfurt document', was Alexander Boom (see 'Main Patent No. 1'). 

(c) Siegfried Apitz is not mentioned as one of the team of engineers or as a co-inventor of the BBG in Herbert Hamann's Erfurt document. His name emerged as one of the co-inventors during my research into the patents later. See my interview with Siegfried Apitz.

Photo: Herbert Hamann giving a talk on the Schaub-Lorenz Music Center
to an audience of ± 92 GFGF members
in the Kaisersaal, Erfurt, Germany, 2008.