B&O Bang & Olufsen BeoVox HT 5700 Passive Loudspeakers type 6253 (serial # 284963, 316889), 1971-76, made in Denmark

Link: beoworld | beocentral

Manufactured: 1971 - 1975
Colours: Rosewood, Teak

Beovox 5700 high fidelity loudspeaker was of studio monitor quality with minimum distortion and maximum power handling capacity.

The loudspeaker was designed to handle 60 watts RMS or 100 watts music power with a distortion of less than 1% over the entire frequency range of 25-20,000 Hz. In order to produce these qualities, Beovox 5700 was fitted with a 25cm ABR (Auxiliary Bass Radiator) unit and a 25cm bass unit which together produced a clear powerful bass reproduction. Its mid-range dome was 5,5cm in diameter and its dome tweeter was 2cm. Dispersion was 160 degrees.

Trumpet stand

Owing to its size, Beovox 5700 could be preferably used as floor-standing speakers. For this reason Bang & Olufsen designed the trumpet stand, type 8906007. This stand had a top on which the loudspeaker could be placed, not only elegantly, but also practically so that a good sound dispersion could be achieved.

Beovox 5700 could be used with Beosystem 4000, an uncompromising stereo system, top of its range in the mid-1970s.

DIN power handling capacity 60 watts
Music power handling capacity 100 watts
Impedance 4 ohms
Frequency range 35 - 20,000 Hz
Harmonic distortion < 1 %
Sensitivity 3 watts
Net volume 45 litre
Woofer: 22,5cm and ABR 25cm
Mid-range 6cm Dome
Tweeter 2cm Dome
Crossover frequency 600 - 6000 Hz
Dimensions W x H x D: 36 x 66 x 30 cm
Weight 22.5 kg

Beovox 5700 Types: 6229 (1972 - April 1974)
Beovox 5700 Types: 6253 (1972 - June 1975)
Beovox 5702 Types: 6257 (1971 - Jan 1975)
Beovox 5702 Types: GB 6251 (1971 - Oct 1973)

Philips AD9710M/01, Fullrange Loudspeaker 8,5 inch - 21,5 cm Alnico 7 ohm, 1971-1977, made in Netherlands

Link: troelsgravesen (chapter II & chapter IIIgo to chapter IV, dissasembling of a 9710 driver.) | radiomuseum | hupse | rutcho

Country: Netherlands
Manufacturer / Brand: Philips; Eindhoven (tubes international!); Miniwatt
Year: 1971

Category: Loudspeaker, headphone or earphone
Wave bands - without
Power type and voltage No Power needed
Loudspeaker Permanent Magnet Dynamic (PDyn) Loudspeaker (moving coil) / Ø 21.6 cm = 8.5 inch
Power out
Model: AD9710M /01 - Philips; Eindhoven tubes
Material Metal case
Shape Chassis only or for «building in» 

  • Philips AD 9710M / 01 High-system perm.-dyn., 10 Watt power handling.
  • Frequency range 30 ... 18000 Hz, 45 Hz natural resonance, impedance 7 ohms.
  • Field strength 8000 gauss (Ticonalmagnet).
  • With tweeter cone, further development of type 9710M.
  • Philips stock number. 2422 258 48,002th
Net weight (2.2 lb = 1 kg) 1.6 kg / 3 lb 8.4 oz (3.524 lb)

Acoustic Research AR-4xa, 31 January 1974, made in USA

Link: link 1 | link 2 | audio-database

System: 2 ways, 2 speaker acoustic suspension system, and a book shelf type
Use unit:
- For low-pass: 20cm corn type
- For high regions: 6cm dome shape
Frequency response: 45Hz - 20kHz
Impedance: 8ohms
Allowable input: Suitable for the amplifier beyond 15W
Crossover frequency: 1kHz
Dimensions: Width 255x height 482x depth of 225mm
Weight: 7.5kg

Monacor SA-500 Solid State Stereo Amplifier (OEM Version Monacor / Monarch SA-500), 1969, made in Japan

Link: radiomuseum | Infrequent Sound | hifi-wiki

Оконечный усилитель собран на: 4 x Sanyo 2SB407 (5K / 5L) Silicon PNP Power Transistors

Наверное, самое ужасное, читать графики но не слушая звук, из первых рук (конденсаторы промеряны):

Country: Germany
Manufacturer / Brand: Monarch, Bremen

Year: 1969-1975 ??
Category: Audio Amplifier or -mixer
Semiconductors (the count is only for transistors) Semiconductors present.
Reception principle Audio-Amplification
Wave bands - without
Power type and voltage Alternating Current supply (AC) / 110; 117; 220; 240 Volt
Loudspeaker - This model requires external speaker(s).
Power out 25 W (40 W max.)
Model: Solid State Stereo Amplifier SA-500W - Monarch, Bremen
Material Wooden case
Shape Book-shelf unit.
Dimensions (WHD) 380 x 130 x 280 mm / 15 x 5.1 x 11 inch

Siehe auch das Modell Monarch Electronics Int'l SA-500W.
Net weight (2.2 lb = 1 kg) 9 kg / 19 lb 13.2 oz (19.824 lb)

  • Hersteller: Monarch
  • Modell: SA-500
  • Typ: Vollverstärker
  • Baujahre: 1969 - 1975
  • Hergestellt in: Japan
  • Farbe: Front Silber, Gehäuse Metall
  • Fernbedienung: -
  • Leistungsaufnahme:
  • Abmessungen (BxHxT): 380 x 130 x 280 mm
  • Gewicht: 9 kg
  • Neupreis ca.: 329 DM

  • Anzahl der Eingänge:
    • Eingangsempfindlichkeit:
    • Phono MM: 3 mV
    • Phono Kristall: 30 mV
    • Tuner: 150 mV
    • AUX: 150 mV
    • Tape Play: 150 mV
  • Anzahl der Ausgänge:
    • Ausgänge:
    • Tape Rec:
    • Kopfhörer:
    • Anschlüsse für 2 Lautsprecherpaare

Technische Daten
  • Dauerleistung (bei Klirrfaktor)
    • 8 Ohm: 2x 22 W
    • 4 Ohm:
  • Dynamikleistung
    • 8 Ohm: 48 W
    • 4 Ohm: 70 W
  • Gesamtklirrfaktor: 1,0 % bei 8 Ohm
  • Dämpfungsfaktor:
  • Frequenzgang: 20 - 20'000 Hz, ± 1 dB
  • Signalrauschabstand:
  • Klangregelung
    • Bass: ± 5 dB bei 100 Hz
    • Höhen: ± 5 dB bei 10 kHz
  • Loudness: ja
  • High Filter: ja
  • Low Filter: ja

Besondere Ausstattungen

  • Mono / Stereo Umschalter

Fera / RFT (Fernseh-Radio) V 150 Quadro-effekt, 1981, made in Germany

The HiFi amplifier V150 is technically the successor to the HiFi 50 and a part of the component system Fera 150 from the PGH TV-Radio Berlin. It is based technically, as well as the rest of the resort, on a proven and reliable switching principle with good technical parameters, but for which also caused no real innovations in the GDR market. ifatwww.et.uni-magdeburg

The amplifier has 5 inputs TA, TB 1, TB 2, Tuner and Reserve (eg for a television set), which can be dialed in an amplifier from the GDR, via a rotary switch instead of push buttons set the first time on the rear panel. The signals of 5 high level inputs are from the rotary switch to a common input amplifier as an impedance converter, which is equipped with low-noise transistors supplied.

The preamplifier is built in classical discrete circuitry. It is equipped with two-stage and low-noise transistors, the tone controls for bass and treble, as well as the volume and balance control is provided by dual potentiometer. The loudness control can be disabled with the "Linear" button continue you can switch to "Mono".

Усилитель является продолжением Fera HiFi 50. radiomuseum | rft-hifigeraete | Infrequent Sound.

Оконечный усилитель собран на: 4 x 2N3055 silicon NPN power transistor 

На днях, на немецком ebay, был продана топовая модель Fera / RFT (Fernseh-Radio) V 500 за 124,45, вы же понимаете, что немцы просто так повышать ставки не будут за усилитель, которые для моих посетителей никогда не представлял интерес. Данную модель впервые увидел, жаль в битве за него участия не принимал, но отмечу, что даже младшие линейки даных усилителей впечатляют. Link: radiomuseum | ifatwww.et.uni-magdeburg | rft-hifigeraete

Сверхнизкий бас! Лютый кач! СЧ-ВЧ можно нерационально регулировать до максимума и получать тот самый песок в тугих АС. Рекомендую для тех кто ищет НИЗКИЙ БАС и яркое звучание. Отличная отработка по динамике.

Pioneer CS-E700, 1973, made in Japan

Link: audio-database

38,500yen(one-set , around the 1973 time)

The 3 way speaker system which adopted the multicellar horn as the high region.

The 30cm unit which adopted FB cone by an original process is adopted as low-pass.
The ferrite magnet is used for the magnetic circuit.

The 12cm unit which adopted FB cone like low-pass is adopted as the mid range.
As for this unit, the ferrite magnet is adopted as the magnetic circuit.
Furthermore, the cone rear is used as perfect closed mold in order to prevent the back pressure from a Woofer.

The multicellar horn is adopted as a high region.

The level control is carried in the front convenient to operate it.
Moreover, a switchpoint change on the back can also use the multi-amplifier scheme of two channels and three channels.

The enclosure serves as oil finish finish of the walnut which employed the beauty of native wood efficiently.

Scheme 3 ways, 3 speakers, a sealing scheme, and a bookshelf type
Using unit
  • For low-pass: 30cm cone type 
  • For mid ranges: 12cm cone type 
  • For high regions: Horn type 
Impedance 8ohms
Play frequency band 35Hz - 20000Hz
Output sound pressure level 93.5dB/W
The maximum input 60W
Cross over frequency
  • 500Hz, 5000Hz 
  • At the time of a multi-amplifier using 
  • Two ways: 500Hz - 1000Hz 
  • Three ways: 500Hz - 1000Hz / 4000Hz - 6000Hz
Dimensions Width 380x height 660x depth of 300mm
Weight 16kg

Dynaco A-25, 1971, made in Denmark

Link: hifiengine | dynacotubeaudio |t-linespeakers | vintage-speaker-review

The classic A25 used a SEAS 10" alnico midbass & a SEAS 1 1/2" alnico treated textile dome tweeter with a 1kHz XO. The later A25XL gained 3 dB of efficiency by utilizing a ceramic SEAS 10" and 1" tweeter


The Dynaco A-25 aperiodic loudspeaker is a compact, high performance two way speaker system.

A 10 inch extended excursion woofer is matched to a specially designed soft dome tweeter with a dual section high pass filter at 1500Hz, in a cabinet design which achieves a uniquely non-resonant bass response.

The aperiodic, or non-resonant characteristic of the A-25 provides an unusally uniform impedance characteristic throughtout the bass range of less than 2 in 1.

This design utilises an acoustic impedance system which provides variable volume action rather than the totally enclosed cabinet of the acoustic suspension principle or the tuned port of the bass reflex.

Type: 2 way, 2 driver loudspeaker system
Frequency Response: 30Hz to 15kHz
Power Handling: 35W
Recommended Amplifier: 60W (maximum)
Crossover Frequency: 1500Hz
Impedance: 8Ω
Bass: 1 x 10" extended excursion
Tweeter: 1 x soft dome
Finish: oiled walnut, rosewood, teak

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