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Bo/ex 521 16 mm projector • magnetic recording • optical and magnetic playback placing all the odds on your side

The Bolex 521 projector projects all 16 mm films whether silent, or magnetic or optical sound. Equipped for recording on the magnetic stripe of th e film, it offers movie-makers all the possibilities and advantages afforded by a highly perfected instrument, such as for example direct mixing, superimpositions and sound fading. Simple to use and handy to carry, the Bolex 521 possesses technical characteristics (automatic threading, variable speed, freezing on a picture, foolproof protection against accidental erasure, etc.) that make it an extremely practical projector, ideally suited to anyone who, without being a professional movie-maker, is required to show documentaries or news films, advertising films, films devoted to research and education in fields such as science, art, sport, industrial techniques, etc.

Variable erasure and grad ual introduction of th e recordi ng, for su perimpositions and simple soun d dissolves or fade-ins and fa de-outs. Regulation of the treble tones du ring di rect ampli fication and playback.

Adjustment of the phono input level.

Main sw itch controlling the fo llowing funct ions : projector stop, forward projection w ithout lamp, forward proj ec ti on w ith lamp at half-power, forw ard projection w it h lamp at fu ll power, reverse motion w ith lamp off (rapid rewind), reverse motion with lamp at ha lf-power.

Ove rvol tag e indicator light.

Sound recording: an ex tremely versatile work tool Direct mixing. During record ing, the sound level is adju sted by means of t w o separate potentiometers, one for m icrophone recording , th e other for phon o recording. The microphone and phono inputs being separa te, you can mi x direct. Superimposition and sound dissolves. A potentiometer for variable erasu re and gradua l introduction of the record ing enables you to va ry from 0 to 100% the level of sound you are recording, whi le reduc ing any previous recording in the same proportion. This makes it extremely easy to carry out superimpositions and simple sound dissolves or fade-ins and fad e-outs. No risk of saturation. A threshold compression device, comi ng into action as soon as a critical reco rding level is reached, instantly redu ces any modulation peaks likely to saturate the magnetic stripe.

Adjustment of t he microphone input level. The recording level can be checked at any time. This check can be either visual , by means of a VU-meter w ith needle lit by an indicator lamp, or aural , by means of a 3 W loudspeaker incorporated in the body of the proj ector, or by means of accessory earphon es. No risk of accidental erasure. Double lock on t he recording: removable key, without which it is not possible to record, and electronic lock operated as soon as the projector is switched to reverse, Gutting out all risk of accid ental erasure.

Adjustment of the bass tones during direct ampli fica t ion and playback.

Swi tch fo r t he ampl ifier and adjustment of th e vol ume during optica l or magnetic sou nd playback .

Selection of the projection speed: 18 f.p .s., 24 f.p .s., from 12 t o 26 f.p.s . (adjustable), free zing on a picture, single-frame operation.

Automatic film threading lever.



Built-in 3 W loudspeaker.

Four-figure frame counter (1 unit= 10 frames).

Setting the frame-counter to zero.

Socket for accessory loudspeaker. VU-meter with needle for checking the recording level.

Adjustment of the angle of projection.

Optical playback indicator light.

Film-cutte r.

Main fuse.

Mains switch.

Mains socket.

Remote-control socket.

Knob cancelling the recording control. Method of operation switch: for silent films, films with optical or magnetic tracks.


Microphone input.

Mains indicator lamp. Adjustment of the speed between 12 and 26 fp.s.

Amplifier indicator light.

Output for auxiliary amplifier or earphones.

Recording knob. Switch fo r preselecting the number of light interruptions per frame and control knob.

Recording lock.

Playback : high quality reproduction of the sound The Bolex 521 projector ensures perfect reproduction of music, words and special effects, thanks to its excellent mechanical and electronic qualities. The amplifier is fully transis to rized; it reproduces a range of frequencies extending from 30 to 20,000 cycles (±3 dB), and its maximum output power (25 W) is ample even for a large hall . In addition, the response curve can be adapted to the acousti cs of any hall by the separate adjustment of the bass and treb le tones . The 10 W loudspeaker, mounted in t he projector lid, gives very good results even in a compara tive ly large ha ll.

Other invaluable advantages

The table below will help you choose the focal length best suited to your needs.

Among all the factors enabling the Bolex 521 projector to work impeccably over a long period of time with the minimum of maintenance, while being particularly easy on the film, the following should be mentioned:

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• the overvoltage indicator lamp, which makes it possible to avoid any prem Cl ture deteri oration of the projection lamp by warning the operator whenever there is any excess voltage;





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• "half-power" setting for the lamp on the main switch (22 V instead of 24 V), which shou ld be used whenever there is any excess voltage or even quite simply in order to lengthen the life of t he lamp w hen co nditions do not requ ire operation at full power;

Width of screen The magnetic heads and optical sound reader, regulated with the greatest precision, are completely foolproof. All speeds are electronically regulated, thus suring excellent stability and eliminating all )w.

Picture reproduction: excellent luminosity and remarkable sharpness A projector is judged above all by the picture it produces on the screen: luminosity, sharpness, maintenance of focus, and freedom from flicker are all-important criteria. Th e Bolex 521 projector produces a picture which close examination shows to fully deserve th e mention "excellent". The 24 V 1250 W halogen lamp, with built-in dichroic mi rror, gives a very bright, ve ry white light throughout its life. The lenses are fully corrected and guarantee a picture perfectly sharp over the whole surface, with good contrasts, as well as impeccable colour rendition. Three lenses are available : 70 mm f / l.6, 50 mm f/l.3, 35 - 65 mm zoom f11.6.

• the powerful fan, ensuring proper cooling of all parts of the projector; The variable shutter, which you can set to either two or three light interruptions per frame, enables you to eliminate the effect of flicker which risks occurring at speeds lower than 24 frames per second . This device also comes in useful depending on the type of film shown, the quality and size of screen.

• the film drive mechanism and the projection gate, which have been designed specially to ensure perfect protect ion of the film;

Simplicity itself to use

• plug-in electronic circuits for easy and quick replacement, thus speeding up repai rs.

Automatic threading. Rapid and reliab le, threading is effected simply by pressing on the threading lever (upper loop former); it is automatic. Variable projection speed. In order to emphasize certain effects or stress certa in movements it is often very useful to be able to slow down or ' speed up projection gradua lly without the spectator noticing any sudden change in speed . This is possi bl e with the Bolex 521 thanks to its regulating potentiometer enabli ng the projection speed to be varied smoothly, between the limits of 12 and 26 fram es per second. Freezing on a picture and single-frame operation. These two methods of operation render invaluable service in the detailed analysis of a movement. Single main switch . A single main switch controls both forward and reverse motion as well as the lighting of the projection lamp. Easy manipulation. All controls have been desig ned to simplify the operator's work to the maxi mum : easily manipulated, th ey are all extremely accessible, and the most f reque ntly used are rational ly grouped on the control panel. Possibility of remote cpntrol. A socket is provided for plugging in a remote control device by means of which a demonstrator or a lecturer, stan ding near the screen for example, can continue to control the operation of the projectorforward or reverse motion, freezing on a picture, and single-frame operation - as well as adjust the vo lume of sound.

• lubrication sufficient for over 500 hours' projection;

Technical specifications General • Sound projector for magnetic recording and optical and magnetic reproduction of sound on 16mmfilm. • Aluminium die-cast body, with plastic lid forming a case. • Dimensions: 480 X 380 x 240 mm, excluding handle. • Weight: approximately 40 lb. • Connection to mains: . a) Universal model with 4-position voltage selector: 118-127-220-240 V, 50/60 cycles; b) European model 220 V150 cycles. Capacity and threading • For use with all standard spools up to 2000 ft. • Automatic threading. Mechanical system • Film driven by electronically regulated low voltage electric motor. • Projection speeds: 18 f.p.s., 24 f.p.s., from 12 to 26 f.p.s. (adjustable by potentiometer), "freezing" on a picture, single-frame projection. • Electromagnetically controlled shutter with 2 or 3 blades. • Rotating main switch with 6 settings. • 4-digit frame counter (1 unit = 10 frames). • Ventilation fan driven by separate motor. • Screw-type feet for adjusting height and level. • Framing adjustment by shifting claw spindle. Lamp and lenses • 24 V/250 W halogen lamp, with built-in dichroic mirror. • Lens-mount, diam. 42.5 mm; focusing by milled knob. • Three lenses to choose from: 50 mm f11.3, 70 mm f/l.6, 35-65 mm zoom f/l.6. Sound system • Fully transistorised amplifier, plugging into the projector in 3 separate units. Power output 25 W with 2% harmonic distortion on 8 Q. Response curve at direct amplification: 30 to 20,000 cycles at ±3 dB. • 3 W built-in loudspeaker (monitor). • lOW loudspeakerfitted in the lid. • Optical or magnetic sound playback volume control by independent potentiometer. • Bass and treble tone control by two separate potentiometers operating during direct amplifica tion and playback. • Operating knob with 3 settings offering the following possibilities projection of silent films with magnetic head retracted, playback of sound recorded on the optical track, magnetic playback and recording. • In all three positions it is possible to give a running commentary via the microphone or record-player inputs. • Separate jack-type inputs for phono and microphone. Phono input from 50 mV to 2 V on 500 kQ. Microphone input from 0.2 mV to 8 mV on 5 kQ.

• Recording level adjustment by 2 separate potentiometers (microphone and phono). These 2 potentiometers also control the volume during direct amplification (live commentary). • Recording level threshold compression device.

• Double locking of recording eliminating any risk of accidental erasure. • Checking of the recording level by VU-meter with needle, lit by a pilot lamp. • Poss ibility of monitoring the recording through loudspeaker (at reduced power) or earphones . • Potentiometer to variable erasure and gradual introduction of recording for superimpositions and sound dissolves. • DIN 2-pin output socket for 8 Q loudspeaker. • Combined DIN 5-pin output socket for 4 to 50 Q earphones and connection to an external amplifier (50 kQ). • Recording/magnetic playback response curve: at 24 f.p.s., from 100 to 12,000 cycles at ±3 dB. Signal/background noise ratio: ~ 50 dB. • Optical playback response curve: at 24 f.p.s., from 50 to 7,000 cycles at ± 3 dB. Signal/background noise ratio: ~ 60 dB. • Wow rate: .:; 0.3%. • Standard sound/picture separations: optical track, 26 frames; magnetic track, 28 frames.

Accessories supplied with the projector • 1 24 V/250 W halogen lamp, with built-in dichroic mirror • 1 2,000 ft. reel with automatic attachment • 1 power cord • 1 record-player jack DIN 5-pin • 1 microphone • 1 brush Optional accessories • Earphones • Wide-screen attachment (ratio of 2.66: 1) for use with 50 and 70 mm lenses. • Wide-screen attachment mount. • Accessory for remote control.

Quality and after-sales service Bolex products are manufactured with the utmost care and are thoroughly tested before t~y leave the factory. They therefore meet the standards of precision and quality that have \ Bolex its world-wide fame. Thanks to its highly efficient international organization, Bolex offers impeccable after-sales service throughout the world. You can entrust your equipment with complete confidence to any Bolex distributor, staffed with highly skilled technicians, usually trained in Switzerland.

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Hallmark of quality

Bolex International S.A. Yverdon ISwitzerland

Bolex International S.A. reserves the right to modify, wit hout prior notice, the design and features of the mode l described in t hi s brochure.

P2-005176 Anglois

Printed in Switzerland

Automatic film threading lever

Framing .


Built-in 3 W loudspeaker .

Four-figure frame counter (1 unit= 10 frames) .

Setting the frame-counter to zero.

Socket for accessory loudspeaker VU-meter with needle for checking the recording level.

Adjustment of the angle of projection .

Optical playback indicator light.

Film -cutter

Main fuse.

Mains switch.

Mains socket.

Remote-control socket .

Knob cancelling the recording control. Method of operation switch: for silent films, films with optical or magnetic tracks. Output for auxiliary amplifier or earphones. Phonoinput. Recording knob. Microphone input.

Switch for preselecting the number of light interruptions per frame and control knob.

Mains indicator lamp. Recording lock. Adjustment of the speed between 12 and 26 f.p.s.

Amplifier indicator light.

Bolex 521 Projector Brochure 7 Pages  
Bolex 521 Projector Brochure 7 Pages