Bang & Olufsen Archives

Bang &#03…

28th 5 月 2022
by giovanni

The High Fidelity Stereo Amplifier 608 was produced from 1961 to 1964 and it's the first Hi-Fi stereophonic amplifier by Bang & Olufsen; that explains its great value, both historical and economic.
The second series had a dark gray front panel but no significant technical changes and together with the Grand Prix receiver it marks a groundbraking step for the Danish firm's design.

The inner set up is a masterful piece of work: cables are put in order and wrapped in a waxed twine binding to create a solid unique body. The power tubes’ polarisation is fixed and each of them has an accurate Bias' control by specific trimmers, as shown in the restoration's photos.
The circuit is very stable due to a 22pF capacitor parrallel connected to a 100 kOhm resistance avoid auto-swinging. The feedback rate is very low.
The power tubes’ set up is ultralinear.
The direct coupling (no capacitors) between the voltage amplifier anode ECC83 and one of the two tubes for the phase splitter is another device's distinctive trait.
A differential circuit realise the phase reversal, in this way a perfect half - waves' symmetry and a remarkable voltage's gain are achieved.
The tones control circuit is a Baxandall, making symmetrical regulation curves (keep scrolling for answer's curves pictures).
Each final stage (two in all) is made up of an ECL85 (so, in total, there are four ECL85). The ECL85 is velvety like ECL86 but more powerful, indeed the rated output is highed than the same series' receiver Grand Prix Moderne Stereo 608.
It's very appreciable the chance to switch right and left speakers phase: if they were connected without paying attention the exact phase can be restored thanks to a switch on the frontal panel. The result, with the speakers in phase, is substantial; voices and solo instruments are clearly distinguishable and the scene take shape.
Not by chance, B&O became the official supplier of the Danish royal house.

This device, designed in an extremely sophisticated way, does not disappoint the listener's expectations: at first a well-finished and sweet sound can be gathered but by turning the volume knob and loudness switch (below in this page) its strengh and intensity are revealed.
A refined design, the charm of an old fashioned and expansive object, a precise and powerful sound and, last but not least, a small number of models, are all features of this fantastic device.

Designer: Architect Ib Fabiansen (1928 – 2009)

Fabiansen started developing modular units for radios and televisions complementing each other with the house forniture and establishing a pleasant surrounding.
In 1958 he made some cardboard models and presented them to Bang & Olufsen management, that immediately approved its production. So he started sketching the Beolit series and other B&O devices, including Hi-Fi Amplifier 608.
In 1962 he designed Beocord Belcanto recorder, Horizont television and so on, until his last creation for B&O, the gramophone TV/radio Beovision 2000RG.
In the last years working for B&O, he cooperated with architecs Henning Moldenhawer an Jacob Jensen.
".. there was a time when it was far from a certainty that a radio from Bang and Olufsen was a study in good design..It was horrible, simply horrible” sayed back then Fabiansen.
Ten years later Jacob Jensen would become the company's chief designer.

To make the most of this device I chose four songs. The first one is “Una ragione di più” by Ornella Vanoni, a beautiful song with lyrics by Franco Califano, Ornella Vanoni and Luciano Beretta, music by Mino and Franco Reitano. Presented in 1969 on the tv show “Senza rete”, the song is about a woman questioning her relationship, and her hard choice between leaving her partner and trying to revive their love from ashes. Ornella's voice is warm, deep and with a great vocal range, which the B&O 608 conveys in all its richness.

The struggle of a love song counterpoints the struggle for exile and oppression is in the second song I propose. It's of an Angolan songwriter, José Adelino Barceló de Carvalho aka Bonga. The title of the song is “Mona Ki Ngi Xica” ad it was written in 1972, while Angola was under Portuguese rule and the author had to flee to the Netherlands because of his politics involvement to free his nation. The lyrics are in Kimbundu, an Angolan dialect. Here, too, a rough and peculiar voice is reproduced in its wholeness by the 608.

Going on with love sufferings (that's the mood of the day), the third track is about a young man and his love, not returned by the girl he loves. It's the well-known song “Say Say Say” by Paul McCartney and Michael Jackson, recorded in 1983 before their quarrel. It seems that McCartney was quite afraid of dancing together with Jackson in the song's videoclip (we can't blame him), but still a true friendship was born, until Jackson bought the Beatles' recording royalties for 47,5 million dollars, snatching them from McCartney and Yoko Ono.

The fourth and last track is Mahler's Symphony N. 5, written between 1901 and 1902. Its theme, sentimental and painful, turns away from the preceding four symphonies, which are about medieval german poetry. The mighty first movement is driven by trumpets and the vigorous orchestral cue does not scare the 608. It's important that the speakers are properly in order.

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.

1925 - Two Danish engineers, Svend Olufsen and Peter Bang, start the production of radio equipment in the attic of the Olufsen family, in Struer.
1927 - The first device, called the “Eliminator” (as it allowed to eliminate the battery power and to connect the device directly to the power grid), is commercialized.
A production plant is built in Struer.
1929 - The "Five Lamper" model (five valves) is marketed and is a great success.
1938 - The beautiful Master 40 model arrives, which allows to memorize stations from the keyboard.
1939 - Beolit 39 is launched, the first radio with a bakelite cabinet. From this moment on, the prefix “Beo” will be used for the most prestigious products of the brand.
1941 - During the German occupation, B&O puts on the market the Grand Prix 42CH which has the characteristic of having a tambour door that covers the scala parlante when it is not used.
1945 - The B&O factory is completely destroyed.
1948 - After a rapid reconstruction of the factory, the production of the Grand Prix 48 CH mobile radio is started, the first high-fidelity radio of the Danish company.
60's - A revolution at B&O. The designer Ib Fabiensen designs the new line of devices, Hi-Fi Stereo Amplifier 608, Grand Prix 608 Moderne, Dirigent 609. Also the Beogram 42 turntable is commercialized. It is with these models that the legendary design of B&O devices begins.
70's - In the 60s and 70s, the devices that make B&O famous in the world are produced. The Beomaster 1200 and 3000, the Beogram 1200 and the Beogram 4002, the beautiful giradischi tangenziale. The devices are designed by Jacob Jensen.
80's - The evolution of design continues with the different Beocenter units and the Beogram cd players.
90's - The company decides to market its products through a network of its own exclusive stores. It expands its interests with the production of mobile phones and Mp3 players.
2008 – It suffers considerable losses and a staff reduction and in the following years it returns to devote itself exclusively to the production of High Fidelity devices.
2015 - B&O becomes a partner of HP.

Year of production: 1961-64

Power supply: 110-220 V - 75W

Loudspeakers: Screw Plugs for External 4-16 ohm loudspeakers

Output power: 15W each channel
Distortion: <0.5 % a 10W, <2 % a 15 W
Channel separation: - 50 dB
Noise level: - 60 dB
Frequency response: 20-20,000 Hz <1 dB
Min. input level:
Magnetic Pickup 2 mV, DIN 45547 RIIAA equalized
Piezo Pickup: 50 mV
Aux: 100 mV,
Microphone: 160 mV
Tuner: 50 mV

Measurements (LAP): 465 x 180 x 208 mm / 18.3 x 7 x 8.2 inch
Net weight: 10.5 kg / 23 lb 2 oz

5 Tubes: ECC83 ECL85 ECL85 ECL85 ECL85
8 Transistors: 2xAC107, 6xAC126(OC75)

In these pictures we can see how much the tune's control system is efficient: in the ones above there's the controls' position in the amplifier, in the ones below the real response curve measured with Wandel&Goltermann WM-20 wobbulator. Measurament done on 4 ohm resistive load.
In the first two pictures on the left we can see the tunes in Flat position: the answer, from 20 to 20000 Hz, stays between ± 1 dB. Others pictures explain themselves.

The device has a remarkable loudness control system. We know that our ears, listening at low volume, perceive better medium frequencies, losing the low and high ones. If low frequency sounds are emitted, medium frequencies are easily perceptible by human ear than low, very low and high ones. That's why, for these listening levels, manufacturers implemented automatic mechanism to amplificate low and high frequencies.

Today this control practice is seen as a forced sound's alteration and is not implemented in amplifiers. Sometimes is not inserted at all, but if it's stil present there's the possibility to exclude it with a knob on the front panel.

On B&O Hi-Fi Amplifier 608 there is a switch for low, medium, high, referring to the listening volume.
With the switch on LOW, loudness control (exalting low and high frequencies) applies at 10 Phon on the Fletcher – Munson curve; with this setting, sound level acheivable operating on volume knob is gentle and is suitable for listening at a low volume.
Putting the switch on MEDIUM, loudness control applies at 50 Phon; low and high frequencies are slightly exalted, you can get a higher sound level and it's good for listening at a medium volume.
With the switch on HIGH there's no more loudness control and response is linear on all frequencies but sound level you get operating on the knob is not maximum. Thanks to this setting you reach amplifier's full power and it's right for listening at its highest volume.

This stadio amplificatore is gifted with noticeable transparency and detail.
The coupling with high-efficiency loudspeakers with neutral tone is therefore very suitable to enjoy these peculiarities to the fullest.
The loudspeakers must be connected with banana plugs on the outputs, respectively:

Højre - Right channel
Venstre - Left channel

The Bang & Olufsen loudspeakers, designed to be coupled to the Grand Prix Moderne Stereo 608, were the Type S (left) and Type L (right) models.
The recordings I posted on this page were made with TRIO-KENWOOD KL333 loudspeakers. I chose these speakers for their efficiency and the very high cut-off frequency that makes them sound almost like full-range speaker.

Beginning from the left in the upper part, the first knob you meet is that of inserting the filters. The switch has 4 positions.

OFF - No filter is active - Linear response
RUMBLE - Very low frequencies are attenuated to avoid reproducing the mechanical noises of the turntable
SCRATCH - The high frequencies are attenuated to attenuate the defects of damaged discs when listening.
RUMBLE + SCRATCH - Both filters inserted
Attentions! The RUMBLE filter introduces a 45 degree phase shift at the cut-off frequency and both filters proportionally attenuate all the frequency band of the respective working range. Avoid using them if possible, better couple the amplifier to a good turntable and treat the records with care.

Below we find the INPUT SELECTOR
PHONO - Turntable with magnetic head
TAPE - Recorder / AUX
RADIO - Tuner / AUX
MICR - Microphone

uncategorised - cn

Bang &#03…

25th 6 月 201928th 5 月 2022
by giovanni

The Grand Prix Moderne Stereo 608 is the first stereo receiver produced by Bang & Olufsen.
From this derives its great historical and economic value.
Produced in 1961, it represents not only an evolution, but a real epochal changeover in the design of the Danish brand.

In the inside, the execution is exemplary. The cables are well arranged and wrapped in a ligature with waxed string that collects them in a single, very solid body.
The power supply consists of an independent block, separate and far from the amplifiers.
The AM / FM radio section is equipped with a medium-frequency double stage to improve the selectivity of the device.
A section of a ECC83 double triode is used to compensate for the attenuation introduced by the Baxandall tone control section.
Very few radios, even among high-class models, were equipped with a Baxandall circuit for tone control. The builders almost always preferred simpler and cheaper circuits, even if the circuit response were not completely symmetrical.
The two amplifiers, one for each channel, are made of a couple of ECL86s. For a total of four ECL86s.
All are mounted on their own vertical board so that the final valves, the four final valves, are arranged horizontally in order to better dissipate the heat. In this way, in fact, the tubes cool uniformly throughout their length.
The triode sections of the ECL86 ensure phase inversion while the pentode sections are connected in Push-Pull and constitute the outuput amplifier.
The power supplied is approximately 10W per channel.
Everything about this device was based on the search for quality. On the other hand, the B&O was proud to be the official supplier of the Danish royal house.

The restoration of this device was thorough.
The amplifier stages have been completely renewed. Each component has been replaced with a high quality correspondent or audiophile.
All the old carbon composite resistors have been replaced, with 10% tolerance but almost all altered and very noisy.
The excellent but unfortunately aged Mustard condensers have all been replaced with Auricap audiophile.
All electrolytics have been replaced with components capable of withstanding high temperatures.
The original bakelite socket of the tubes have been replaced with new high-quality ceramic sockets and high-quality gold contacts.
The valves have been selected all with equivalent characteristics, so as to avoid imbalances between one channel and another.

The results of this excellent project and of the very high quality of the components used in the process are the extreme definition and the sweetness of reproduction.
I believe the Grand Prix Moderne Stereo 608 is especially suitable for recordings with voices or solo instruments.
New Age and electronic music is reproduced with great satisfaction.
The fact that this warm and precise sound is played by a fascinating and rare machine from the 60s just complements the invaluable magic.

The sweetness this machine impresses me with makes me think that it might be possible to use it in music therapy or sound baths. Although for this purpose the use of live instruments is unsurpassed.
But this is a complex and controversial topic and it will be the subject of in-depth studies and discussions in the future.

The first track of the playlist I chose in order to test this device is Sit tecum timor suus, from Giacomo Carissimi's Historia di Job (Marino 1605 - Rome 1674).
It belongs to the musical genre called Oratorio, and in particular of the Oratorio in Latin and with a biblical subject, of which Carissimi is one of the greatest exponents.
This musical genre has very ancient origins, as it comes from Passions and Mottetti. This is very interesting, because being detached from the liturgical function it exalted the practice of music for the purpose of spiritual elevation. Music as an instrument of diffusion of elevated principles was strongly pursued by Filippo Neri who, similarly to the Lutheran rite, intended to bring the evangelical message closer to the people.
Going back to Carissimi, chapel master in the Basilica of Assisi and then choirmaster in the Germanic College of St. Ignatius of Loyola in Rome, in the Historia he uses both monody and polyphony, emphasizing, according to some critics, the expressive power of the work. From the manuscripts it appears clear that the instrumental element is the pipe organ, rarely accompanied by bowed or wind instruments.
After Carissimi, the Latin Oratorio will lose importance while the vulgar Oratorio will continue to be practiced.
In Naples, Alessandro Scarlatti writes La Vergine Addolorata, a mature work with alternating refrains, arias and instruments that accompany the recitative. This use of the orchestra brings the work closer to the genre of drama. The second track of the playlist is drawn from this wonderful Oratorio.
In Venice the Oratory, clashing with the profane melodrama prevailing at the time, is expressed in the works of Giovanni Legrenzi, Baldassare Galuppi and Benedetto Marcello, up to Juditha triumphans by Antonio Vivaldi, which will be discussed in a future review.

BLUETOOTH

Bluetooth receiver embed

MULTI PLATFORM CONNECTION

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

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.

Højre - Right channel
Venstre - Left channel

The Bang & Olufsen loudspeakers, designed to be coupled to the Grand Prix Moderne Stereo 608, were the Type S (left) and Type L (right) models.
The recordings I posted on this page were made with Grundig 306A loudspeakers. I chose these loudspeakers for their detail and for the very deep bass they can express.

The front side can be imagined as divided into two horizontal sections.
In the upper part, the first knob is that of the volume with built-in loudness.
Coaxially, the ferrite antenna control knob can be seen.
Then, we see the AM scale for short, medium and long waves. The FM scale.
In the center we find the Magic Eye, which indicates the best tuneing of the different stations.
On the right of the dialglass, then, we see the two separate tuning controls.
The rear knob, bigger, controls the FM band.
The frontal knob, smaller, controls the AM bands.