graetz - cn Archives – Luxuryradios

Graetz Si…

22nd 3 月 202422nd 3 月 2024
by giovanni

From World War II until the 1960s, Graetz was considered one of the most prestigious radio manufacturers, although it never achieved high sales performance due to the high cost and economic conditions of Europe at that time.
Graetz devices have always been appreciated both for their refined and elegant finish but above all, for the constant search for innovative acoustic solutions and the related patents.
The Sinfonia series is the most prestigious Graetz production with a class A final stage.
Among these, the SINFONIA 522 is the last one equipped with Raumklang mit Schallkompressor (Surround sound with Compressor). Subsequent models, certainly for economic reasons, will be deprived of this ingenious, but expensive, sound diffusion system.

The Schallkompressor will be described in depth later on the page, suffice it to say for now that some speakers spread the sound through a specially designed path which made it impossible to locate exactly where the sound was coming from, making listening exactly identical in all points of a room .

The medium-high tones spread in all directions through the grille, which looks like a simple decoration, placed on the upper side of the cabinet.

The resulting effect is exciting, a sweetness of the high tones deriving from the front cone tweeter, combined with a depth of the bass caused by the muscles of the two large woofers, with a breadth of the sound image, deriving from the compressed flute supertweeter, which has no equal in monophonic devices.
I'm not talking about high fidelity of course, but about very pleasant sonic rapture.

Graetz had 4 lines of devices with ShallKompressor:
- Music (the smallest, 1 woofer, 1 mid, 1 tweeter)
- the Melody (the medium, 2 woofers, 1 mid, 1 tweeter)
- the Sinfonia (the big one, 2 bigger woofers, 1 mid elliptical, 1 elliptical tweeter)
- the Fantasia (like the Symphony but with 2 EL95 power amps instead of one EL84)

Great radios, with a very pleasant sound, to listen to for hours.

FM FREQUENCY RANGE

FM frequency range widened from 88 up to 108 MHz

BLUETOOTH

Bluetooth receiver embed

MULTI PLATFORM CONNECTION

Each radio is equipped with a cable for connection to any digital device.

- FM frequency range winded from 88 up to 108 MHz - The tube radios produced in Germany in the years 50/60 are famous worldwide for their excellent sound quality, the beauty of their furniture, their strength and for their construction standards without compromise. Unfortunately the FM band extending from 87.5 to 100 MHz for which are scarcely usable in most cases. After careful study and a lot of tests we were able to obtain a frequency range by this unit from 88 to 108 MHz . We have also reconstructed a display exactly identical to the original, made with the same materials and the same techniques, but with the new frequency span. The result is perfect. An original device, but with the ability to listen all stations in any country.
– Bluetooth receiver embed – The unit is equipped with a BLUETOOTH receiver powered directly by the receiver power supply. This makes it possible to control the amplifier from any external digital device as an IPAD, a Smartphone, or a sophisticated multimedia station. So you can hear your preferred web station or your lossesless file without cables on the room. Wireless Receiver can be equipped upon requests.
– Multi Platform Connection – A customized adaptation cable to connect any digital device as Iphone, Smartphone, Laptop, CD Player etc. will be provided with this radio. This special cable suits the different impedances between the modern equipment and the receiver. Furthermore the two stereo channels flow into one without increasing the load to the input unit.

The Ehrich & Graetz metalworks was a factory established in 1866 in Berlin by Albert Graetz (1831–1901) and the tradesman Emil Ehrich (died 1887) under the name “Lampen-Fabrik Ehrich & Graetz OHG” (E&G).
By 1897 the firm was controlled by Albert’s sons, Max Graetz, and Adolf Graetz. The company grew rapidly, and in 1899 a factory complex were built in Berlin, in the United States, France, the UK, and Bombay.
Around 1910-1916 Max Graetz developed the famous Petromax Lantern. Around 1925 the factory also produced radios, and other electrical appliances under the name Graetzor.

In the Second World War, just as in the First World War, the company was part of the war industry. With the use of forced laborers from France, Russia, and the Netherlands the company made huge gains in production.
At the end of April 1945 the factory was claimed by the Russian army.

In 1949 the firm became part of the “peoples” program, “VEB-VolksEigenerBetrieb” and since 1950 “VEB Fernmeldewerk, Berlin Treptow (RFFT).” VolksEigenerBetrieb, means that the factory was owned by the people for the people (Communism).

In 1948 Erich, and Fritz Graetz founded a new company in Altena, Germany known by the name The Graetz Firm, which was successor to the lost family company in Berlin. The new company produced mainly radios, and televisions.
In 1961 the company was then sold to Standard Elektrik Lorenz (SEL) AG, but since 1987 has been to the present owned by the Finnish company Nokia.

In the natural evolution of the Sinfonia at Graetz model they began to use horn loudspeakers.
Horn speakers have the advantage of having a very small and light membrane. This translates into an ability to reach very high frequencies with very low distortion.
Like all musical instruments, this type of speaker is composed of a sound generator and a resonator. In a violin the strings vibrate and emit the sound, but it is the sound box that amplifies and colors it.
In horn speakers the small and very light membrane vibrates and then the horn amplifies, and sometimes modifies, the sound.
The trumpet has the disadvantage of being highly directive. A few cm from its axis the intensity of the sound changes considerably. The horn system, although very efficient and with low distortion, is not suitable
Graetz engineers preferred a tuned pipe instead of the horn due to its greater directionality characteristics.
The pressure of the sound wave goes with the square of the ratio between diameter and length of the tube. For this reason at Graetz they talk about a sound compressor.
So from the small emission of the cone membrane a large sound radiation is obtained at the exit of the tubes.
Furthermore, since the ratio between length and diameter of the pipe is very large, propagation similar to propagation on a duct of infinite length is obtained. The output slots are placed at different distances to achieve this non-resonant effect. The equivalent scheme is that of an LC circuit where the holes behave like inductors.
The result of this characteristic, combined with the particular shape and position of the sound output slots, is that the resonance frequency is around 12 kHz and this system is made to work in the range from 700 Hz to 10 kHz, precisely where the maximum sensitivity of the human ear, and where the voice and almost all musical instruments are located.
In addition to the advantages of absence of distortion and efficiency, the absence of resonances results in a notable softness of listening.
Lastly, this duct produces a slight delay, of a few ms, which by inducing a minimum natural reverberation obtains as a final effect that scenic depth which makes this device incredibly satisfying to listen to, despite being monophonic.

As previously mentioned, Schallkompressor means Surround Sound with Compressor.

I would like to point out that this company applied these concepts and these solutions (surround, sound compression) to commercial equipment, and it was 1958.

As everyone now knows, bass notes by their nature spread omnidirectionally in the environment, so it is rather difficult to locate a subwoofer with your eyes closed.
The speakers that spread the high notes, on the other hand, are extremely directive, so their positioning in relation to the listening position is very critical, so it is enough to move a little from the intended listening position to lose part of the message and detail of the highest part of sound information.

This problem has been addressed in the evolution of Hi-Fi systems with the most diverse systems.
Graetz solved this extremely effectively at the time with the 4R system in the previous Sinfonia models and the Schallkompressor in the models from 422 onwards.

On the left there is the volume control (with built-in loudness) and axially to this the rotation control of the ferrite antenna.
Above you can see the antenna position indicator.
The magic eye that indicates the perfect tuning of each station.
The AM scale for Long, Medium and Short Waves and the FM scale up to 108 MHz.
Below from the left we find in order the bass control knob, the power buttons, turntable, recorder, the buttons for receive Long Waves, Medium Waves, Short Waves, FM, the treble control knob.
The frequency band involved is indicated when you push each button.
Finally, there is the tuning knob, whose movement is very pleasant as it is supported by a large flywheel.
Below again we find the two large knobs for bass and treble control.
Axial to the tuning knob there is a selector for controlling selectivity in AM.
The registers and the exclusion buttons have been seen previously in detail.

german radios - cn

Graetz Fa…

25th 4 月 202327th 3 月 2024
by giovanni

162w - cn

Graetz 16…

13th 5 月 20206th 6 月 2022
by giovanni

The review of the Graetz 162W is different from all the reviews ever published.

Starting from this one, the reviews will be accompanied by a section with graphs of technical measures of the most important parameters.
There is no such thing anywhere else, as far as I know. Not even the manufacturers themselves detailed the technical features of their own devices at this level.
This new section has been developed for an objective comparison of different devices.
In order to avoid interpreting the measurements incorrectly, it is very important to read the warnings carefully the first time.

When it was decided to restore and test the Graetz 162W, expectations were quite high. Actually, the 162W differs from the 163W, top model of the Graetz production in 1952, only for the output tube, one of the two speakers and some other minor details. Moreover, both of these devices have very interesting circuit choices which provide them with a very peculiar sound.
First of all, they are both equipped with an electromagnetic coil loudspeaker and a permanent magnet loudspeaker. The permanent magnet loudspeaker, with a smaller diameter, has a greater extension towards medium and high frequencies. The electromagnetic coil loudspeaker has a considerable extension towards the medium-low frequencies. The two speakers are connected in series, there is no a crossover network between the two, the separation of frequencies is entrusted to the mechanical characteristics of the speakers themselves. Both of them will be examined in detail in the specific section.

The FM section is also very peculiar. The HF section is entrusted to an EF80 Variable transconductance . The same tube is used simultaneously as a audio preamplifier. In the diagram here, the HF circuit is highlighted in blue and the audio stage one, instead, is highlighted in red.

The Audio Section is entrusted to a EL41 pentode EL41 working in A Class.
The Volume potentiometer is equipped with a loudness pinout. It is known, in fact, that when listening at very low volume, the low and acute notes are not perceived with the same sound intensity as the medium notes, which clearly prevail.
The loudnes circuit changes the curve response of the preamp section specularly to the Fletcher–Munson curve. This allows to keep the perception of the extreme sounds of the audible audio spectrum constant even at low volume levels. The Tone Control, separate bass and treble, is inserted in the feedback network.

Conclusions: a warm and mellow sound was what one would expect from the Graetz 162W, and this is even its most evident feature. The absence of a real tweeter makes it necessary to emphasize the treble to get a balanced response. The treble control effectively solves the problem. The efficiency of the two loudspeakers and the very contained distortion give this radio a powerful voice, despite the limited power available. The tuning is very stable. The interfacing with external sources, CD players, bluetooth etc. is free of any problem. Its graceful shape, the choice and the processing of the wood and its musicality make it a very enjoyable and reliable device.

The recordings made with the Graetz 162W are all dedicated to the dawn of Jazz. Listening to such songs with this device was particularly exciting, given the dominance of medium tones and voices. The old recordings have shown an unusual charm and it is worth listening to them.

The first song is one of the first and most peculiar Negro-American ballads, Frankie and Albert in the famous interpretation of Huddie Ledbetter.

Leadbelly, stage name of Ledbetter, that derives from a bullet never extracted from his belly, had a very busy life. From 1910 to 1930 he was arrested several times, in Texas and Louisiana, for fighting, attempted murder, for getting some girls pregnant.
In the last years of his turbulent life finally came a good success in the music field, which even got him to a tour in Europe.
http://www.leadbelly.org/
The ballad talks about Frankie, a good and devoted woman, and about her lover, Albert, a deadbeat and violent, who betrays her. The long ballad talks about Frankie's revenge who kills him by shooting him and who, after asking for Albert's mother's forgiveness, is sentenced to the the electric chair.
The story refers to a real fact that happened in 1899 in Missouri between Frankie Baker (22 years old) and Allen (Albert) Britt (17 years old).

The second song is a Pianola Roll recording of the very well-known Maple leaf Rag, played by Scott Joplin.
This recording on Roll for piano, thought to be lost, was found on Ebay mounted on a wrong player. The perforated roll has been restored and recording is freely available on Youtube.
The American Civil War has been over for three years, misery, hunger, rebellions, they are tough years in the States. There is a need for cheerful music to lift the spirits and Ragtime comes at the right time. Born as art music, difficult to perform, it finds in Joplin its greatest exponent. Born in Texas, he started playing in the infamous clubs of Missouri and then moved to New York.
The Ragtime develops in four themes of sixteen themes according to the AABBACCDDL scheme. The beauty of the songs here proposed lies in the syncopated rhythm played with the right hand accompanied by the 2/4 not syncopated time played by the left hand. For M.Stearns, in “The story of Jazz” the left hand is inspired by the rhythm of the European school march, the right by the way of playing the Banjo proper to the black musicians of the South.

A white New Orleans musician who deserves to be remembered is Paul Mares.
The third and fourth tracks proposed are his famous foxtrot “She's Cryin' For Me” in Mares' original version and in the Au Brothers Jazz Band's interpretation.
Paul Mares moved to Chicago in 1919, created the famous New Orleans Rhythm Kings. The orchestra was mainly formed by white immigrants from New Orleans, they played at Friar's Inn, in the heart of white Chicago, a place frequented by gangsters such as Al Capone. Mares is to be credited for bringing New Orleans' musical soul to Chicago.

The Au brothers owe their musical talent to their uncle, a High Sierra trombonist, Howard Miyata. The quality of the execution and the arrangements restore the freshness and panache that characterized this last century music at its beginnings. The proposed recording has both the strengths and weaknesses of live recordings.

BLUETOOTH

加装蓝牙接收器

MULTI PLATFORM CONNECTION

每台收音机都配备了一条连接到任何数字设备的音频线。

- 蓝牙接收器加装-该单位配备了一个蓝牙接收器，直接由收音机供应电源。这使得有可能控制放大器从任何外部数字设备作为一个iPad，智能手机，或一个复杂的多媒体站。所以你能无线听到您喜欢的网站或你的无损档案。无线接收器可根据要求选配。

– 多平台连接-一个定制的适应电缆连接任何数字设备，如iPhone，智能手机，笔记本电脑，CD播放器等将提供这台收音机。这种特殊的电缆适合现代设备和接收机之间的不同阻抗。此外，两个立体声信道流入一个不增加负载的输入单元。

Ehrich & Graetz金属制品厂由Albert Graetz（1831–1901）和商人Emil Ehrich（死于1887）以“Lampen-Fabrik Ehrich & Graetz OHG” (E&G). 为公司名称成立于1866年柏林。
到1897时，公司由Albert的儿子Max Graetz和Adolf Graetz控制。公司发展迅速，1899分别在柏林、美国、法国、英国和孟买建立工厂。
在1910-1916 年Max Graetz成立了著名的Petromax Lantern公司。1925年工厂也以Graetzor公司名稱開始生产收音机和其他电器。

就像第一次世界大战一样，在第二次世界大战中该公司成為战争工业的一部分。随着来自法国、俄罗斯和中国的强迫劳工的使用，该公司在生产上取得了巨大的收益。
1945年四月底这家工厂被俄国军队占领了。

1949年公司成为“人民”计划的一部分，自1950年成為“VEB VolksEigenerBetrieb” “VEB Fernmeldewerk, Berlin Treptow (RFFT).” VolksEigenerBetrieb,，意味着工厂的人拥有者是人民（共产主义）。

1948年Erich和Fritz Graetz在德国Altena成立了一家新的公司名稱為Graetz公司，这是Graetzor在柏林遭沒收的家族公司的继任者。这家新公司主要生产收音机和电视机1961年公司再卖给Standard Elektrik Lorenz (SEL) AG，但自1987年以来一直到现在由芬兰Nokia公司拥有。

MEASURED TECHNICAL FEATURES

IMPORTANT REMARK
(to be read carefully at least the first time)

The following measures have been carried out in order to compare, from an electrical point of view, the devices that will be reviewed on this site. It is not possible to make comparisons with measurements made by other laboratories on different devices. The instrumentation and measurement conditions are probably very different.
The instrumentation used for the measurements is obsolete and unprofessional. We believe that more precise instrumentation is not necessary due to the tolerances of the human auditory system. Distinguishing a distortion of 1% from one of 1.1% or 1.001% only makes sense from the electrical point of view. Probably no one can hear the difference by ear. Only a child and very few lucky people can perceive the difference between a flat response curve up to 16 KHz and one up to 20 kHz.
The perception of sound depends on many factors, namely the age of the listener, the listening environment, the musical genre that is being reproduced, the listener's expectations, his or her listening habits and knowledge and many other factors, besides of course the quality of the other devices. Therefore, there is no direct and unique relationship between the results of the measurements made and the pleasantness of listening to a specific device.

BANDWIDTH

The frequency response curve was detected on resistive load by measuring the RMS voltage at different frequencies and converting the results into DB.

The BLUE line indicates the bandwidth with the tone potentiometer in a flat position.
The RED line indicates the bandwidth with the tone potentiometer in the position of maximum exaltation.

The bandwidth was measured on resistive load. Therefore, it does not take into account the deformations deriving from the inductive load of the loudspeakers and their mechanical response.

RMS POWER

We consider as Maximum Power the square of the lower of the RMS voltages measured at the three sample frequencies divided by the load resistence.
The measurement conditions are the following:
- sample frequencies, 100, 1000, 10,000 Hz
- 8 ohm resistive load
- distortion less than or equal to 1%.
The measuring instrument provides the RMS value directly.

The measured RMS power is 3.4 W

INTERMODULATION DISTORTION %

The Intermodulation Distortion % was measured with the SMPTE standard and measured at 1W RMS.
The two measurements were carried out by modulating the 50 Hz sine wave with a 1080 Hz sine wave and then with a 10400 Hz sine wave, with an amplitude in a ratio of 1/4 compared to the basic sinusoid.
The output voltage was kept around 2.83V on an 8 ohm carico.

The measured Intermodulation Distortion % (IM%) is 0.8%

IM% at 1000 Hz

IM% at 10.000 Hz

The speakers of this radio are one of the most interesting and peculiar characteristics of such device.

The larger of the two measures approximately 24 cm in diameter and is electrodynamic. Instead of having a Permanent Magnet, like all modern cone loudspeakers, the static part called field coil, inside which runs the moving coil that drives the cone, is made up of an electromagnet. A winding of very fine wire which, when traversed by electricity, becomes a magnet.
In this speaker, branded Graetz BV8191 model, the winding consists of 11,000 coils of 0.18 mm copper wire. The static resistance of the winding is 950 ohms.
Being the winding of the field coil connected between the two power supply filter capacitors it also works as an inductor of the LC filter, thereby significantly reducing the ripple at the output of the second filter capacitor.
Finally, it can be seen in the photos that this speaker has a concentric fold in the cone. This has two functions. The first one is to reinforce the cone, for which a thinner and lighter membrane can be used allowing a more prompt response and less inertia. The second is a mechanical insulation between the central part of the cone and the external part.
The central part of the cone is the one that reproduces the high tones, which in this way is more elastic than the entire cone, allowing an upward extension of the frequency response.

The second speaker is an Isophon P18 / 19/105 with permanent magnet, 18 cm in diameter, and a frequency response that extends from 90 to 10,000 Hz within 3 dB.
Connected in series to the bigger loudspeaker, it reinforces the whole band in general and, above all, it extends upwards the extension of the entire system.
It is a speaker with a fairly light cone, with an Alnico magnet and a magnetic flux density of 10,500 Gauss. The speaker is very dynamic and efficient. The complete features are indicated in the chart.

By pulling the knob, a switch is activated which halves the anode voltage of all the tubes. In this way there is a decrease in the brightness of the magic eye and a decrease in the wear of all the tubes. The power supplied is also decreased and this allows a better management of the volume control at low levels. In fact, with the same angular rotation that normally allows to go from the lowest to the highest level, with the anode volatge and therefore also the power halved, the potentiometer allows to go from zero to about half the volume, becoming easier to adjust. This function is especially useful for night listening.

german radios - cn

Graetz Me…

13th 2 月 2019
by giovanni

La Graetz Melodia 14F si distingue immediatamente dagli altri apparecchi prodotti nella metà degli anni 60 dalla prestigiosa marca di Berlino per il look modernissimo che faceva largo uso di metalli e plastiche.
Questo interessante esperimento di design lo si ritrova, oltre che sulla Melodia 14F, solo sul modello Stereo Unit 250.
Confrontando, nelle foto a destra, il modello Melodia 1118 finita di produrre solo l'anno prima e la Melodia 14F , non si può non rimanere impressionati dall'incredibile evoluzione stilistica dei due apparecchi.

Da sempre i prodotti Graetz sono stati caratterizzati da design ricercato e curatissimo, ma negli anni '60 c'è stata una vera e propria accelerazione anticipando uno dei più grandi movimenti creativi degli anni 70 conosciuto sotto il nome di "Space Age".
Dalla famosissima "Ball Chair" del grande designer Finlandese Eero Aarnio, alla Lampada Eclisse dell'italiano Vico Magistretti.
La Space Age sperimenta nuovi materiali e questo rende possibile esplorare forme nuove, precedentemente difficili da realizzare.
Molte aziende realizzano in quegli anni degli insuperati "oggetti" tecnologici oggi molto ricercati.
Tra i produttori di apparecchiature tecnologiche cito solo, oltre naturalmente alla Graetz con la Melodia 14F Stereo Unit 250, la Grundig con la serie di diffusori acustici HI-FI sferici AudioRama e l'italianissima Brionvega con la sua Tv Algol e la Radio cubo.

Nel 64 Charles Mingus lascia il contrabbasso per registrare l'album "Mingus Plays Piano", debuttano i "The Velvet Underground", e "The Who", in Italia si forma il gruppo "I giganti" e concludo la recensione rubandogli il loro grido di battaglia - Mettete dei fiori nei vostri cannoni ...

La Sezione Amplificatore è composta da una EL84 in classe A per ciascun canale, pilotata da una sezione del doppio triodo ECC83.
Il potenziometro di Volume è dotato di presa per la correzione fisiologica. (Giallo). Come noto infatti quando si ascolta a volume molto basso le note basse e quelle acute non vengono percepite con la stessa intensità sonora delle note medie, che appaiono nettamente in prevalenza.

Il Controllo di bilanciamento (Blu) è inserito tra i due canali all'uscita del preamplificatore.

La Rete di Controreazione (Rosso) è stata progettata per ridurre la distorsione ed equalizzare la risposta in frequenza dell'apparecchio. Infatti l'apparecchio è dotato di autonomi altoparlanti per ciascun canale. Questi altoparlanti pur essendo a larga banda e di ottima qualità non sono in grado di riprodurre fedelmente l'intera banda udibile. la loro risposta in frequenza infatti decade agli estremi, in particolare quello basso. Il circuito di controreazione compensa le cadute di efficienza dei diffusori ai due estremi della frequenza. Il risultato è una risposta sorprendentemente lineare su una banda di frequenze molto estesa. Non ci si aspetta un suono del genere da diffusori così piccoli, e questo è il modo in cui è stato ottenuto.

Anche la Sezione Radio è molto curata.
La caratteristica più interessante è l'elevata selettività di questo apparecchio dovuta al doppio stadio di Media Frequenza. Infatti sono visibili nelle foto i due pentodi EF89 ed i numerosi trasformatori MF.
In FM è stato implementato addirittura un ulteriore trasformatore accordato all'interno del convertitore per rendere ancora più stabile ed insensibile ai disturbi la ricezione di queste frequenze.

Infine la batteria di Altoparlanti.
La Graetz 922 Luxus monta 6 altoparlanti. Quattro altoparlanti sono disposti frontalmente e due sono collocati ai lati.
I quattro altoparlanti frontali sono due tweeter e due ellittici largabanda. I tweeter sono posti davanti ai largabanda, sullo stesso asse. Questa particolare disposizione ha il grande vantaggio che la provenienza del suono è assimilabile a quella prodotta da una sorgente puntiforme.
Questa caratteristica si traduce in un diagramma di dispersione molto lineare, e quindi di una acustica nell'ambiente molto più regolare che non se tweeter e woofer fossero disposti uno in fianco all'altro.
I due altoparlanti laterali sono, a questi livelli di potenza, dei Mid/Tweeter, e permettono un ascolto equilibrato da qualunque posizione ci si ponga rispetto alla radio, frontalmente o lateralmente.

Quest'ultima caratteristica rende l'apparecchio molto godibile nell'ascolto quotidiano. Non verrà più voglia di accendere l'impianto stereo ...

BLUETOOTH

Bluetooth receiver embed

MULTI PLATFORM CONNECTION

Each radio is equipped with a cable for connection to any digital device.

- Multi Platform Connection - A customized adaptation cable to connect any digital device as Iphone, Smartphone, Laptop, CD Player etc. will be provided with this radio. This special cable suits the different impedances between the modern equipment and the receiver. Furthermore the two stereo channels flow into one without increasing the load to the input unit.

The Ehrich & Graetz metalworks was a factory established in 1866 in Berlin by Albert Graetz (1831–1901) and the tradesman Emil Ehrich (died 1887) under the name "Lampen-Fabrik Ehrich & Graetz OHG" (E&G).
By 1897 the firm was controlled by Albert's sons, Max Graetz, and Adolf Graetz. The company grew rapidly, and in 1899 factory complexes were built in Berlin, in the United States, France, the UK, and Bombay.
Around 1910-1916 Max Graetz developed the famous Petromax Lantern. Around 1925 the factory also produced radios, and other electrical appliances under the name Graetzor.

In the Second World War, just as in the First World War, the company was part of the war industry. With the use of forced laborers from France, Russia and the Netherlands the company made huge gains in production.
At the end of April 1945 the factory was claimed by the Russian army.

In 1949 the firm became part of the "peoples" program, "VEB-VolksEigenerBetrieb" and since 1950 "VEB Fernmeldewerk, Berlin Treptow (RFFT)." VolksEigenerBetrieb, means that the factory was owned by the people for the people (Communism)

In 1948 Erich, and Fritz Graetz founded a new company in Altena, Germany known by the name The Graetz Firm, which was successor to the lost family company in Berlin. The new company produced mainly radios and televisions.
In 1961 the company was then sold to Standard Elektrik Lorenz (SEL) AG, but since 1987 has been to the present owned by the Finnish company Nokia.

Gli altoparlanti sono due Lorez LP 1318/19/105 AF con magnete in Alnico. Sono molto efficienti. I 4 Watt di ciascuno dei due canali viene trasformato così in una notevole pressione acustica.
Per un ascolto a volume "normale", non fastidioso, la manopola viene posizionata ad ore 11.
La potenza sonora quindi è abbondantemente sufficiente per sonorizzare anche ambienti di medie dimensioni.

In tal modo la risposta dinamica è molto pronta, ed i bassi sono frenati ma molto presenti.
Questa caratteristica permette di sfruttare appieno l'ingresso AUX con file digitali lossesless o CD fornendo una riproduzione brillante e ricca di dinamica.

922 - cn

Graetz Fa…

23rd 10 月 20187th 6 月 2022
by giovanni

Graetz is one of the most prestigious German radio manufacturers. The Graetz Fantasia 922 Luxus - Stereosuper was the flagship model in 1960.
Graetz devices have always been appreciated for their refined and elegant finish, as much as for the innovative acoustic solutions and their respective patents.
In designing the line of their flagship model, Graetz designers chose a classical and statuary kind of elegance.
The cabinet is in dark wood and the paint is very shiny. The sides with their variable width make the profile look slimmer. The base looks wide and solid, without making cabinet look heavy.
The strongly embossed texture of the canvas covering the speakers, the golden lines highlighted on the dark display and the light knobs make the visual impression even more pleasant and lively.
The stylistic attention, as in Graetz's tradition, is very accurate.

The Amplifier Section is the best that could be imagined at the time.
The Volume potentiometer has two sockets for loudness (red). As known, in fact, when listening at a very low volume the bass frequencies and the treble are not perceived with the same sound intensity as the mid, which appear to be predominant.
The loudness modifies the response of the preamplifier stage specularly to the Fletcher-Munson curves. This allows to maintain the correct perception of the sound, even at low volume levels.

The Tone Control was designed using the complex Baxandall circuit (green). The advantage of such circuit is its high precision, while the disadvantages are its cost and construction complexity. Much simpler and cheaper circuits were normally used. But not in this device.

The Balance (pink) is inserted into the feedback circuit. It works by changing the percentage of signal that is downgraded/relegated to each of the two channels. This signal is in inverted phase compared to the main signal. In this way, by acting on the balance, the level of one channel is lowered in comparison with the other and, at the same time, the distortion is reduced.
By turning the knob at the ends, this type of balance does not cause a reset of the volume of the channels as in the modern balance control, but it is to be considered a “fine” adjustment of the level between the two channels.

The Phase Inverter (blue) is of the Catodina type. As an advantage, it is very well-balanced. This circuit is still used in hi-fi amplifiers.

The Push-Pull section (blue) uses two separate tubes (EL95) for each channel. The EL95 are pentodi expressly designed for audio use.
In the receivers, even high-class, provided with Push-Pull output power, bulbs were normally used, which enclosed multiple valves (ELL80, ECLL800). In this way, space and components were saved. But if one of the pentods inside thei complex tube decays differently, the reproduction is altered, with an exponential increase in the crossover distortion. These multiple tubes, once common, are rare and expensive today, so the replacement can be economically significant. The use of separate pentods, as in the Graetz Fantasia 922, eliminates this problem, and it is possible to select pairs of EL95 with the same characteristics.
Only the Graetz Fantasia 922 and 1022 and the Telefunken Opus 2430/2550 use 4 x EL95 in the stadio finale.

The Tuner Section is also very well taken care of.
The most interesting feature is the high selectivity of this device, due to the twin IF stage. The two EF89 pentods and the numerous IF transformers, in fact, are visible in the photos.
In FM an additional transformer has been implemented, accordato all'interno del convertitore in order to make more stable and insensibile ai disturbi the reception of such frequencies.

Finally, the L0udspeakers set.
The Graetz 922 Luxus features 6 loudspeakers. Four are placed frontally and two on the sides.
The four front loudspeakers are two tweeters and two oval wideband. The tweeters are placed in front of the wideband, on the same axis. This particular arrangement has the great advantage of making the origin of the sound close to that produced by a point source.
This characteristic corresponds to a very linear scatter diagram, and therefore to a much more regular realistic sound image than if the tweeters and the woofers were placed side by side.
The two loudspeakers placed on sides are, at such power level, the mid / tweeters, and allow a balanced listening from any position with respect to the radio, frontally or sideways.

This last feature makes the device very enjoyable as for daily listening. You will no longer want to turn on the HI-FI system ...

BLUETOOTH

Bluetooth receiver embed

MULTI PLATFORM CONNECTION

Each radio is equipped with a cable for connection to any digital device.

- Bluetooth receiver embed - The unit is equipped with a BLUETOOTH receiver powered directly by the receiver power supply. This makes it possible to control the amplifier from any external digital device as an IPAD, a Smartphone, or a sophisticated multimedia station. So you can hear your preferred web station or your lossesless file without cables on the room. Wireless Receiver can be equipped upon requests.
- Multi Platform Connection - A customized adaptation cable to connect any digital device as Iphone, Smartphone, Laptop, CD Player etc. will be provided with this radio. This special cable suits the different impedances between the modern equipment and the receiver. Furthermore the two stereo channels flow into one without increasing the load to the input unit.

In 1948 Erich, and Fritz Graetz founded a new company in Altena, Germany known by the name The Graetz Firm, which was successor to the lost family company in Berlin. The new company produced mainly radios and televisions.
In 1961 the company was then sold to Standard Elektrik Lorenz (SEL) AG, but since 1987 has been to the present owned by the Finnish company Nokia.

As previously mentioned, the most luxurious model produced by Graetz in 1960, the Fantasia 922, features 6 permanent magnet speakers.
The low and middle notes are reproduced by two large conical speakers, elliptical 26x17 cm.

High-pitched notes are reproduced by four cone loudspeakers. Two measuring 10 cm and two 6cm.

From the acoustic point of view, the interesting thing is not only the number of loudspeakers, but also their placement. The two 6 cm tweeters, in fact, are attached to the frontal Mid/Woofer, in a concentric position.
This is always my favourite placement and it is used in many of the best modern diffusers, such as KEF, TAD and Tannoy and many more.
The main advantage of a coaxial is the linearity of the off-axis response, both on the horizontal and vertical plane.
With the traditional positioning of the loudspeakers, the mid/woofer next to the tweeter, the off-axis listening is consistently disturbed by the phase cancellations caused by the length differences of the route between the two drivers.
The 3D graphics on the side display the measurements off the vertical axis of a box with coaxial loudspeaker KEF LS50 and one with traditional positioning of the YG Anat III. The difference is noticeable. (source: www.acousticfrontiers.com )

While frontally such an excellent configuration was used, what was done laterally is no less. In fact, on each side was installed a cone tweeter, protected by a metallic dome, Isophon HS10.
This loudspeaker has a very wide frequency response, from 1.000 to 20.000 Hz. So that all frequencies with pretty strong directivity features are reproduced also laterally.
The response to low frequencies is entrusted to the big frontal elliptics. In fact, low-frequency waves – as they are not directive by nature – do not need lateral loudspeakers in order to be perceived.

With this set of loudspeakers placed as described, the response is clearly quite linear from all angles, frontally, laterally and three-quarter.

As they are loudspeakers with an Alnico magnet, they are very efficient. The 7 Watts of each of the two channels are transformed into a noticeable acoustic pressure.
To provide a reference, during the listening at “normal” volume, not bothersome, a 0,2 Watt power delivery on the loudspeakers is measured.
The sound power is thus amply sufficient to sonorize even large environments.
The use of two separate Mid/Woofers has another advantage. The cones have less inertia compared to a larger single cone. In this way, the dynamic response is quick, and the lows are curbed and without resonance.
This feature allows to make the most of the AUX-in with lossesless digital files or CD, providing a brilliant reproduction rich in dynamism.

The tones control system is very efficient. Above the large tone control knobs there is a band that lights up gradually indicating the emphasis on the band on which it acts.

By pushing any of the Klangregister buttons, the tone-controls are excluded, since the frequencies connected with the chosen button are enhanced.
For this reason, the lights that enlighten the scale which indicates the tone-control position are turned off, too. They can be turned on again by pushing the Raumklang button and switching back to the manual setting of the favourite response curve.

Inside the cabinet there is a dipole for FM reception and a ferrite rotating aerial for AM reception.
Ferrite aerial can be rotated from the outside to achieve a perfect tuning of the device in the AM.
In this picture you can see the rotation mechanism, and the aerial position indicator.
The reception sensitivity with internal aerials is very good. This unit was in fact produced when there were not many radio stations, and those available were far from each other.
Using an external aerial sensitivity is further increased.

Left from the top:
- The Magic Eye that indicates the perfect tuning of each station.
- The antenna position indicator.

- The volume control (with built-in loudness)
- Axially this balancing.
- The rotation command of the ferrite antenna is still in axis.

- The bass control knob

In the center:
The AM display for long, medium, short waves and the FM display.

Right from the top:
The BANDBREITE indicator (High / Low selectivity in AM)
The tuning knob, whose movement is very pleasant being supported by a large flywheel
On the same axis there is a selector to control the selectivity in AM.
-The treble control knob.

177w - cn

Graetz Sp…

8th 3 月 201725th 4 月 2023
by giovanni

The Graetz Spitzen Super 177W is the most prestigious Graetz radio produced in the early 50s. “Spitzen Super” means extra strong, the device’s vocation.
This device is huge and does not hide its pride of being on the A list. The cabinet, in my opinion, is the best among the Graetz devices. The wood flames are deliberately noticeable and give the cabinet a certain lightness. Its blunted edges and again lighten the overall aspect of the cabinet.

The sound of this device is rather smooth and its knobs can be turned without twitches. Tuning stability is given by the heavy fly-wheel located on the same axis of the control and ensuring inertia.

The power stage is a push-pull of two EL84 like many other later Hi-Fi amplifiers. The remarkable loudspeaker array with a huge wide band elliptical woofer, an elliptical midrange and a cone tweeter on the backside.
The sound is powerful and very precise. Graetz favored sound quality over pure power and wanted to document the details of this choice. Further on, on this page, you can find an entire section describing the actions made on this device. Usual profound bass, medium is there and acute is sharp. Clearly the valve final creates no problem with the listening.

This Graetz is certainly the result of an accurate study and of an expensive project in order to be among the best at that time.
The counterreaction circuits are very complex and tone controls are inside them, so that the emphasis given to the controls varies according to the volume. This effects adds to the fact that the circuit is equipped with a more than one stage loudness. When the acute sounds are at the highest the medium AM bell-shaped curve can be changes with the help of a switch integrated in the potentiometer. By doing this the acute sounds of that band can be further raised.
Many other remarkable elements characterize this device. An example is the number of condensers employed. A beautiful high quality device, with a fascinating aesthetics, perfectly functioning and with a powerful and “cozy” sound.

BLUETOOTH

Bluetooth receiver embed

MULTI PLATFORM CONNECTION

Each radio is equipped with a cable for connection to any digital device.

In 1948 Erich, and Fritz Graetz founded a new company in Altena, Germany known by the name The Graetz Firm, which was successor to the lost family company in Berlin. The new company produced mainly radios and televisions.
In 1961 the company was then sold to Standard Elektrik Lorenz (SEL) AG, but since 1987 has been to the present owned by the Finnish company Nokia.

Inside the cabinet there is a dipole for FM reception and a ferrite rotating aerial for AM reception.
Ferrite aerial can be rotated from the outside to achieve a perfect tuning of the device in the AM.
In this picture see the rotation mechanism and the position indicator of the aerial.
The reception sensitivity with internal aerials is very good. This unit was in fact produced in a period when there were not many radio stations and those available fairly apart from each others.
Using an external aerial sensitivity is further increased.

On the left side you can see the volume control knob (with incorporated loudness).
On the same axis there is the regulation of the ferrite aerial.
On the right the magic eye indicating the perfect tuning of each station.
Below the bass tones indicator and further below its control knob.
The Long, Medium, and Short Wave AM scale and the FM scale.
On left-hand corner on the bottom the Off, record player, recorder buttons and those for Long, Medium 1, 2, Short and FM Wave bands.
On the right the treble indicator and its control knob.

Preamplifier - Sine Wave - 1000 Hz
Preamplifier - Triangle Wave - 1000 Hz
Preamplifier - Square Wave - 1000 Hz
Inverter stage - Triangle Wave - 1000 Hz
Anode output power tubes - Sine wave - 1000 Hz
Output on own loudspeakers - Square wave - 1000 Hz
Output on own loudspeakers - Sine wave - 20 Hz
Output on own loudspeakers - Sine wave - 100 Hz
Output on own loudspeakers - Sine wave - 5000 Hz
Output on own loudspeakers - Sine wave - 15000 Hz

graetz - cn

Graetz Me…

6th 3 月 201716th 2 月 2024
by giovanni

The Melodia M618 is the radio with the most modern design produced by Graetz in those years.
No radio in those years had a design somehow similar to this. It is of the end of Fifties that we are referring to.
This is the reason why I wanted to dedicate a page of my website to it.

Its design gave me the opportunity to take pictures of it with modern furniture. But it is when I put it among elements of colonial style that its impact became astonishing.
Warm colours, soft wood, natural sound that only tubes can give. It looked like radio and furniture were designed together.

Technically this device has everything available at the time.
Separated tone controls. Three curves set equalizer. Two frontal widerange loudspeakers, a frontal cone tweeter and a double sided flutes horn tweeter.
Class A power amplifier with the wonderful classic EL84.

Tuning is stable and sharp on every band.
This is an easy radio to find a place to, because of its reasonable measures.
All in all, a true little jewel.

BLUETOOTH

Bluetooth receiver embed

MULTI PLATFORM CONNECTION

Each radio is equipped with a cable for connection to any digital device.

In 1948 Erich, and Fritz Graetz founded a new company in Altena, Germany known by the name The Graetz Firm, which was successor to the lost family company in Berlin. The new company produced mainly radios and televisions.
In 1961 the company was then sold to Standard Elektrik Lorenz (SEL) AG, but since 1987 has been to the present owned by the Finnish company Nokia.

The first objects you meet on the left is the magic eye indicating the perfect tuning of each station and below the bass tones indicator.
Then you can see the volume control knob (with incorporated loudness).
On the same axis there is the ferrite aerial orientation knob.
The Long, Medium, and Short Wave AM scale and the FM scale.
On the right the tuning knob and further the treble tone indicator.
Below we see the bass control, the Off, record player, recorder , Ferrite Aerial buttons and those for Long, Medium, Short and FM Wave bands, and further the treble control knob.

german radios - cn

Graetz Si…

29th 1 月 20176th 4 月 2023
by giovanni

从第二次世界大战到60年代，Graetz被认为是最负盛名的无线电制造商之一，在那个年代由于在欧洲的高成本和经济条件，它从来没有达到高销售业绩。
Graetz设备一直被赞赏是因为他们的准确和优雅的做工，最重要的是，不断创新和专利的声学解决方案的研究。
SINFONIA 4R／221在1955 / 1956年是Graetz生产中最著名的系列核心产品，配备Rundstrahl-Raumklang durch Klangkompressor（全方位环绕声压缩机）。
我们将进一步看看Graetz创新的音响系统；喇叭声音传播通过特定的设计路径精确地查找出声音是非常重要的，以使房间的所有点获得完全相同的听觉效果。

中高音频是由一个看似装饰网格放置在机箱的上侧向四面八方传播。
此效果令人激动。由于巨大的低音单元安装于机箱前端内，大片的共鸣板使得低音是非常深和非常强的；高音清晰，明亮和愉快的。

声音的印象是如此的广泛，饱满而丰富，整体的音响效果让你一见钟情，甚至是当第一个音符响起。
希腊庙宇式的机箱是非常好和坚固，比例平衡，其不对称性令人印象深刻的。
正如预期的那样，极致的修复完成。

这收音机所有的设计都是令人兴奋的，从敏锐的按键和坚固的机械噪声，到愉悦柔和的音调和音量控制，直到伴随着调谐旋钮运动令人安心的大飞轮。由于其两阶段的中频调谐高度准确和稳定。但为什么会有人不想买它？SINFONIA 4R依然是一个相当昂贵的收音机，这可能真的是唯一的原因！

FM频率范围

调频频率范围从88扩大到108兆赫(MHz)

蓝牙

加装蓝牙接收器

多平台的连接

每台收音机都配备了一条连接到任何数字设备的音频线。

- FM频率范围从88到108兆赫---在1950 / 60年代德国生产的电子管收音机是世界闻名的，这是因为他们出色的声音质量，他们美丽的机箱外型，他们的实力和他们没有妥协的作业标准。不幸的是，FM频段只有从87.5~100兆赫，但无法接收到100兆赫以上的电台，经过仔细的研究和大量的测试，我们能够获得的频率范围由原有范围扩大至88~108兆赫。我们还重建了一个与原始完全相同的玻璃面板，用相同的材料和相同的技术，且与新的频率范围对应，结果是完美的。使我们可以在任何国家收听到所有的FM电台。

Musica 和 Melodia兩型號没有太多的分享，Sinfornia 4R这个型號是被设计来满足当代富有的发烧友的需求。
这台收音机的声音一直很出色。
当这项修复完成后，我有机会聆听美妙的NBC交响乐团- Harmonia Mundi，G小调大协奏曲“Christmas”的发烧版。音乐播放器是我的Marantz CD94 MKII插入
录音磁带输入。
經由SINFONIA 4R听交响乐真是令人兴奋的，甚至比听我自己的音响更精彩，虽然他们都对我很苛刻的标准定制。
下面，详细介绍，从声音扩散系统开始。