Original subtitles

Narrator: WHEN IT COMES TO SOUND QUALITY,

AUDIOPHILES SWEAR BY AMPLIFIERS WHICH CONTAIN

VACUUM TUBES TO BOOST AND MODIFY THE ELECTRICAL SIGNAL.

THEY WERE THE NORM UNTIL TRANSISTORS CAME ALONG

IN THE 1950s.

MANY AUDIO ENTHUSIASTS STILL PREFER TUBE SOUND,

WHICH THEY FIND WARMER, RICHER, AND MORE NATURAL.

ONCE STANDARD IN RADIOS, PHONOGRAPHS, AND TELEVISIONS,

TODAY YOU SEE VACUUM TUBES ONLY

IN VERY HIGH-END AUDIO EQUIPMENT.

THEY COME IN AN ARRAY OF MODELS DESIGNED TO PERFORM SPECIFIC

SOUND-ENHANCING TASKS.

TECHNICIANS AT THIS CZECH FACTORY FIRST WIND WIRE

A PRECISE NUMBER OF REVOLUTIONS

WITH A VERY SPECIFIC DEGREE OF TENSION.

THEN THEY CLEAN THE SURFACE AND WELD IT TO A SUPPORT STRUCTURE.

THIS COMPLETES THE GRID, ONE OF THE TUBE'S MAIN COMPONENTS.

NEXT, TECHNICIANS TAKE THE SECOND MAIN COMPONENT,

THE CATHODE, AND INSERT IT INTO THE GRID.

WHEN THE SOUND SIGNAL ENTERS THE TUBE,

THE CATHODE PRODUCES A FLOW OF ELECTRONS.

THE GRID CONTROLS THAT FLOW

AS IT TRAVELS TO THE THIRD MAIN COMPONENT, THE ANODE.

THE ANODE'S TOP SECRET BLACK COATING

INCREASES THE EFFECT OF THE ELECTRONS HITTING IT,

CAUSING THE ANODE AND CATHODE TO HAVE TWO DIFFERENT VOLTAGES,

BOTH OF WHICH ARE GREATER THAN THAT OF THE ORIGINAL SIGNAL.

THIS MAKES THE SIGNAL LARGER AND MORE POWERFUL,

MEANING IT AMPLIFIES THE SOUND.

WITH THOSE THREE COMPONENTS NOW ASSEMBLED INTO ONE UNIT,

THE INSIDE STRUCTURE OF THE TUBE IS COMPLETE.

NOW FOR THE BULB, WHICH WILL ENCASE THE UNIT.

A GLASS BLOWER SKILLFULLY CRAFTS

IT OUT OF HARD, LABORATORY-GRADE GLASS.

USING A HIGH-TEMPERATURE TORCH AND GLASS-MAKING TOOLS,

HE MELTS THE OPEN END AND SEALS IT OFF.

THEN HE BLOWS IN A BIT OF AIR

TO SHAPE THE END INTO AN EVENLY ROUNDED DOME.

NOW HE MOUNTS THE BULB ON A LATHE TO COMPLETE THE SHAPING.

KEEPING THE GLASS EVENLY HEATED,

HE BLOWS IN JUST ENOUGH AIR PRESSURE TO KEEP THE BULB

FROM COLLAPSING INWARD.

WHEN THE GLASS REACHES JUST THE RIGHT TEMPERATURE,

A DIE PRESSES AGAINST IT, SETTING THE FINAL SHAPE.

NEXT, THEY MOUNT A GLASS COLLAR

OVER COPPER WIRES CLAMPED INTO A MOTORIZED VICE,

THEN INSERT A GLASS STRAW CALLED AN EVACUATION PORT.

AS THE VISE ROTATES, THEY HEAT

THE COLLAR UNIFORMLY WITH STATIONARY TORCHES.

USING A HANDHELD TORCH,

THEY REMOVE ANY STRETCHES OR RUNS IN THE SOFTENING GLASS.

WHEN THE TIME IS RIGHT, THEY ACTIVATE A DIE

TO PRESS THE GLASS INTO THE FINAL SHAPE.

THIS COMPLETES THE STEM ON WHICH

THE TUBE'S INSIDE STRUCTURE SITS.

THE WIRES PROTRUDING FROM THE TOP OF THE STEM

CONNECT TO THE STRUCTURE'S TERMINALS.

NOW THEY PUT THIS ASSEMBLED UNIT ON A TURNTABLE

AND CENTER THE BULB OVER IT.

AS THE TURNTABLE REVOLVES, THEY HEAT THE BOTTOM OF THE BULB.

AS THE GLASS MELTS, THEY PRESS IT INWARD,

FUSING IT TO THE STEM.

THEY REMOVE THE EXCESS GLASS AND CONTINUE HEATING

TO ENSURE THE BOTTOM IS FULLY SEALED.

NEXT, THEY PREPARE TO SUCTION OUT THE AIR.

THIS STEP IS CRITICAL TO THE TUBE'S PERFORMANCE,

BECAUSE AIR MOLECULES HINDER THE FLOW OF ELECTRONS.

TECHNICIANS FUSE THE TUBE'S EVACUATION PORT

TO THE GLASS EVACUATION LINE OF A VACUUM PUMP.

THE PUMP THEN EXTRACTS THE AIR THROUGH THE PORT.

AT THE SAME TIME, THEY HEAT THE TUBE IN A PULL-DOWN OVEN.

THIS INCREASES PRESSURE INSIDE THE TUBE,

CREATING A STRONGER VACUUM.

NEXT, THEY RUN AN INDUCTIVE HEATER OVER THE TUBE.

THIS DISLODGES DAMAGING IMPURITIES,

ENABLING THE VACUUM PUMP TO DRAW THEM OUT.

THEY TARGET THE STEM AREA WITH A SECOND INDUCTIVE HEATER

TO DRAW PARTICLES CALLED IONS ONTO THE GLASS PERMANENTLY

SO THAT THEY CAN'T LATER DAMAGE THE TUBE.

FINALLY, THEY CONNECT THE PROTRUDING WIRES

TO A PLASTIC PLUG-IN BASE.

THERE ARE SUBTLE TECHNICAL DIFFERENCES BETWEEN TUBES

OF THE SAME MODEL.

SO THE FACTORY TESTS EACH TUBE,

THEN MATCHES PAIRS WITH SIMILAR PERFORMANCE FEATURES.

THIS ENSURES THEY'LL AMPLIFY SOUND EVENLY.

Narrator: A LIGHT BAR IS THAT STRIP OF FLASHING LIGHTS ON TOP

OF A POLICE CAR OR EMERGENCY VEHICLE.

THE LIGHTS ARE HIGH-OUTPUT L.E.D.s,

FAR MORE EFFICIENT AND DURABLE THAN INCANDESCENT

OR QUARTZ HALOGEN BULBS OR STROBE TUBES.

THE MOUNTING SYSTEM IS DESIGNED

TO WITHSTAND EMERGENCY HIGH-SPEED DRIVING.

THE L.E.D.s ARE GROUPED BY COLOR WITHIN A MODULE.

MODULES CAN BE ARRANGED IN ANY CONFIGURATION

ON THE LIGHT-BAR BASE.

THE BASE MOUNTS TO THE VEHICLE'S ROOF

VIA STRAPS MADE OF HIGH-STRENGTH STAINLESS STEEL.

THOSE STRAPS BEGIN AS FLAT PIECES,

LASER CUT TO A STARTING SHAPE.

A 50-TON FORMING PRESS BENDS THEM TO THE FINAL SHAPE,

WHICH FITS THE EXACT CONTOUR OF THE VEHICLE'S DOORJAMB.

THE LIGHT BAR'S WHITE LIGHT MODULES FASTEN ONTO THE BASE

WITH THE ALUMINUM BRACKETS THIS WORKER IS ASSEMBLING.

THESE BRACKETS ALSO HELP DRAW

OUT THE HEAT THE LIGHTS GENERATE.

THIS IS CRITICAL, BECAUSE IF L.E.D.s OVERHEAT, THEY BURN OUT.

THE BASE IS MADE OF EXTRUDED ALUMINUM.

THIS COMPUTER-CONTROLLED LASER, WORKING ON SIX BASES AT A TIME,

CUTS OUT HOLES FOR VENTING AND CABLES.

THE LIGHT BAR HAS TWO CABLES --

ONE RUNNING POWER FROM THE VEHICLE'S BATTERY

TO THE LIGHT BAR AND ANOTHER CONNECTING

CONTROL SWITCHES ON THE DASHBOARD

TO THE LIGHT BAR'S ELECTRONIC CONTROL BOARD.

AN AUTOMATIC MACHINE MEASURES AND CUTS THE REQUIRED LENGTH

OF EACH CABLE, THEN STRIPS OFF A SPECIFIC AMOUNT

OF THE PVC OUTER JACKET AT BOTH ENDS.

THIS EXPOSES THREE WIRES,

TWO OF WHICH ARE INSULATED AND INSIDE A FOIL WRAP.

AFTER STRIPPING OFF THE FOIL,

AN AUTOMATIC STRIPPING MACHINE REMOVES SOME INSULATION,

BEARING THE TIN-COATED COPPER WIRE WITHIN.

WORKERS PUT CONTACTS ONTO TWO OF THOSE WIRES --

THE GROUND AND THE POWER --

THEN PRESS THE CONTACTS ON SECURELY

WITH A CRIMPING DEVICE.

NEXT, THEY CONNECT A TERMINAL TO THE THIRD WIRE,

THE SHIELD DRAIN.

THIS WIRE REDUCES ELECTRONIC INTERFERENCE

FROM SOURCES LIKE THE POLICE RADIO.

NOW FOR THE L.E.D. LIGHT MODULES,

THE MAIN COMPONENT OF WHICH IS A REFLECTOR.

THEY PUT THE REFLECTOR'S PLASTIC BODY INTO THE SEALED CHAMBER

OF A METALIZING MACHINE.

THE MACHINE THEN RELEASES ARGON GAS

WHILE APPLYING HUNDREDS OF VOLTS OF ELECTRICITY

TO A SOLID PIECE OF ALUMINUM.

THIS VAPORIZES THE METAL INTO TINY PARTICLES,

WHICH A VACUUM DRAWS ONTO THE PLASTIC BODY

IN AN ULTRA-THIN REFLECTIVE COATING.

TO BROADEN THE HORIZONTAL RANGE OF THE REFLECTION,

WORKERS INSTALL A DEVICE CALLED A COLLIMATOR.

THEN THEY TAKE AN L.E.D. LIGHT,

PUT AN ELECTRIC INSULATOR ON THE BACK OF IT...

AND MOUNT IT INSIDE A HOUSING THAT'S SPECIFICALLY DESIGNED

TO REMOVE HEAT FROM THE L.E.D.s.

THEN THEY INSTALL THESE ASSEMBLED LIGHT COMPONENTS

IN THE REFLECTOR...

INSTALL THE CONNECTOR THAT PLUGS INTO THE WIRE HARNESS

THAT LEADS TO THE CONTROL BOARD...

...AND TEST THE FINISHED MODULE.

TO ASSEMBLE THE LIGHT BAR,

THEY SLIDE THE CONTROL BOARD ONTO THE BASE,

PLUG IN THE CONTROL CABLE THAT CONNECTS THE BOARD

TO THE DASHBOARD SWITCHES,

INSTALL THE POWER CABLE THAT RUNS

FROM THE VEHICLE'S BATTERY TO THE LIGHT BAR,

AND THE WIRING CONNECTING THE LIGHTS TO THE BOARD.

AFTER MOUNTING THE WHITE LIGHT MODULES ON THE BRACKETS

AND SECURING THEM TO THE BASE,

WORKERS TAKE THE COLORED L.E.D. MODULES

AND SLIDE THEM ONTO THE TRACKS ON THE BASE.

THEY MAKE THE INTERNAL CONNECTIONS

TO THE CONTROL BOARD,

THEN PLUG EACH MODULE INTO THE CONTROL BOARD HARNESSES.

AFTER TESTING TO MAKE SURE EVERYTHING WORKS PROPERLY,

IT'S JUST A MATTER OF ENCASING THE MODULES,

STARTING WITH AN ALUMINUM TOP,

THEN SLIDE ON TRANSPARENT PLASTIC LENSES

WITH DIVIDER GASKETS IN BETWEEN

TO PREVENT RAIN FROM PENETRATING AND SHORTING OUT THE LIGHT.

A CAP CLOSES UP EACH END.

AFTER A FINAL ROUND OF TESTING,

THE LIGHT BAR IS READY TO HIT THE ROOF AND THE ROAD.

Narrator: FLYING A WOOD MODEL AIRCRAFT IS A WAY TO EXPERIENCE

THE ADVENTURE OF FLIGHT ON A SMALL SCALE.

BUT THERE'S A LOT TO DO BEFORE TAKEOFF.

THESE MINIATURE PLANES USUALLY COME IN KITS

THAT CAN TAKE DOZENS OF HOURS TO PIECE TOGETHER.

BUT, OF COURSE, THAT'S JUST PART OF THE FUN.

WOOD MODEL PLANES ARE PART OF AVIATION HISTORY.

THE FIRST REAL FLYING MACHINES WERE MADE OF WOOD,

AND SOON AFTER THEIR INVENTION,

PEOPLE BEGAN BUILDING MINIATURE WOOD REPLICAS IN KIT FORM.

TODAY MODERN MANUFACTURING TECHNIQUES TAKE THE CONCEPT

TO A WHOLE NEW LEVEL.

PRODUCTION BEGINS WITH BLOCKS OF WOOD THAT CIRCLE ON A SYSTEM

OF CONVEYORS.

EACH TIME AROUND, A LONG BLADE SLICES AWAY A THIN PIECE.

THEY TRANSFER THE SHEETS OF WOOD TO A TABLE

THAT MOVES IN A COMPUTER-CHOREOGRAPHED SEQUENCE

WHILE LASERS OVERHEAD MAKE CUTS.

THIS COMPUTERIZED SYSTEM PRODUCES PARTS

THAT WILL FIT TOGETHER PERFECTLY,

NO MATTER HOW INTRICATE THE DESIGN.

TO ASSEMBLE THE KIT AT HOME,

THE MODELER EXTRACTS THE PRECUT PARTS.

HE THEN BUILDS THE FUSELAGE RIGHT ON TOP OF THE PLANS

IN ORDER TO FOLLOW THEM TO THE LETTER.

AFTER THE FUSELAGE HAS BEEN ASSEMBLED,

HE FOCUSES ON THE WINGS.

HE BRACES THE MAIN SPAR WITH NUMEROUS RIBS

TO CREATE A CROSS-SECTIONAL AIR FOIL

THAT WILL GENERATE LIFT.

HE THEN GLUES THE WINGS' LEADING EDGE TO THE FRAMEWORK.

THE FRAMEWORK IS VERY SIMILAR TO THAT OF FULL-SIZED WOODEN WINGS

BUILT IN THE EARLY DAYS OF FLIGHT.

IT'S MADE MAINLY OF TROPICAL BALSA,

A WOOD THAT'S BOTH LIGHTWEIGHT AND EXCEPTIONALLY STRONG.

THE MODELER JOINS THE TWO WINGS.

THE TONGUE OF ONE FITS INTO THE LASER-CUT SLOT OF ANOTHER.

THIS JOINT WILL LATER BE GLUED TO REINFORCE IT.

HE DEMONSTRATES THE NEXT STEP USING THE WING OF ANOTHER MODEL.

HE DRAPES PLASTIC FILM OVER THE WING'S SKELETON.

HE TACKS THE PLASTIC TO IT

AND SMOOTHES OUT RIPPLES AND BUBBLES.

HE THEN HEAT-SHRINKS THE PLASTIC

TO GIVE THE MODEL AIRCRAFT ITS TIGHT SKIN.

OF COURSE, THERE'S NO NEED FOR A PAINT JOB

BECAUSE THE PLASTIC IS TINTED.

FINALLY, HE CONFIRMS THAT IT'S DRUM TIGHT.

BACK ON THE PRODUCTION LINE,

THEY'RE NOW WINDING WIRE TO PRODUCE A SPRING.

THIS SPRING IS A SHOCK ABSORBER

FOR THE PLANE'S FRONT LANDING GEAR.

WITH THAT COMPLETE,

THEY NOW POSITION A SHEET OF PREHEATED PLASTIC

ABOVE SIX MOLDS OF WHEEL COVERS.

HE ACTIVATES A VACUUM THAT PULLS THE PLASTIC OVER THE MOLDS.

IN SECONDS, IT COOLS AND SOLIDIFIES INTO THE SHAPE

OF THE WHEEL COVERS, CALLED PANTS.

WITH THE WHEEL PANTS ASSEMBLED TO THE CRAFT,

THE MODELER NOW INSTALLS THE TWO-STROKED

ALCOHOL-BURNING ENGINE IN THE FRONT COMPARTMENT.

HE ATTACHES THE MUFFLER TO THE ENGINE'S CRANK CASE.

HE THEN SECURES THE SPINNER'S BACK PLATE AND PROPELLER

ONTO THE ENGINE'S DRIVESHAFT WITH A WASHER AND BOLT.

THIS ASSEMBLY WILL HAVE TO WITHSTAND THE FORCE

OF THE SPINNING PROPELLER, SO HE TIGHTENS IT TO THE MAX.

AND THIS MODEL PLANE IS NOW READY FOR FLIGHT.

INCREDIBLY, IT STARTED OUT AS A BUNCH OF PARTS IN A BOX,

BUT THEY ALL COME TOGETHER

IN THE HANDS OF A SKILLFUL MODELER.

OF COURSE, A GOOD SET OF INSTRUCTIONS IS ESSENTIAL.

ASSEMBLING EACH MODEL CAN TAKE UP TO 50 HOURS.

WE'VE JUST SHOWN THE HIGHLIGHTS.

THE PAYOFF COMES WHEN THE OPERATOR

MANIPULATES THE TRANSMITTER JOYSTICK

AND THE PARTS OF THE PLANE MOVE RIGHT ON CUE.

FROM FIGHTER PLANES AND BIPLANES TO CIVILIAN AIRCRAFT

AND EXTREME AEROBATIC MACHINES,

WHEN IT COMES TO THESE HISTORICAL REPLICAS,

THE SKY REALLY IS THE LIMIT.

Narrator: THE SOUND OF A SNARE DRUM IS UNMISTAKABLE --

A SHARP RATTLE WITH A SOMEWHAT TINNY RESONANCE.

WHAT PRODUCES THIS DISTINCTIVE SOUND?

IT'S A VIBRATING SET OF WIRES CALLED THE SNARE WIRE

STRETCHED ACROSS THE BOTTOM OF THE DRUM.

THE SNARE DRUM IS THE CENTER OF THE DRUM KIT.

THE CIRCULAR FRAME OF A SNARE DRUM, CALLED THE SHELL,

CAN BE MADE OF EITHER WOOD OR METAL.

METAL SHELLS PRODUCE A SHARP, LOUD, AND MORE BRILLIANT SOUND.

THE METAL THIS GERMAN DRUM COMPANY USES

IS KNOWN AS BELL BRONZE,

WHICH IS APPROXIMATELY 78% COPPER AND 22% TIN.

WORKERS FIRST GLUE TOGETHER A THREE-PART MOLD.

IT'S MADE OF A SAND AND CHEMICAL MIXTURE

BECAUSE SAND CAN WITHSTAND THE TEMPERATURE

OF THE HOT MOLTEN METAL.

THE GLUE SETS IN ABOUT HALF AN HOUR, AND THE MOLD IS READY.

THEY STEADY IT WITH HEAVY STEEL PLATES,

THEN SCOOP A BUCKET FULL OF BELL BRONZE

FROM THE FURNACE AND POUR IT IN.

IT TOOK FOUR HOURS AT 2,300 DEGREES FAHRENHEIT

TO MELT THE METAL,

BUT JUST A FEW SECONDS FOR IT TO SOLIDIFY

INSIDE THE MOLD CAVITY.

THEY LET THE CASTING COOL FOR A COUPLE OF HOURS,

THEN BREAK THE SAND MOLD TO EXTRACT IT.

THEY CLEAN OFF THE LOOSE SAND WITH A WIRE BRUSH,

THEN SHIP THE SHELL TO THE DRUM FACTORY,

WHERE ITS FIRST STOP IS ONTO AN AUTOMATED LATHE.

AS THE LATHE SPINS, A CUTTER SKIMS OFF A THIN LAYER OF METAL,

MAKING THE SHELL'S EXTERIOR SURFACE CLEAN AND SMOOTH.

NEXT, A COMPUTER-GUIDED DRILLING MACHINE BORES 47 HOLES

FOR VARIOUS COMPONENTS,

INCLUDING FITTINGS THAT HOLD AND ADJUST

THE DRUM HEADS AND A VENT HOLE

THAT INCREASES THE DRUM'S VOLUME.

THEN THE MACHINE CHANGES THE DRILLING TOOL FOR A MILLING TOOL

AND MAKES TWO RECESSED AREAS CALLED SNARE BEDS

IN THE SHELL'S BOTTOM EDGE.

THE DRILL LEFT ROUGH EDGES,

SO THEY CLEAN AND SMOOTH THE HOLES

WITH A SMALL GRINDING TOOL.

THEN THEY MANUALLY SAND THE SNARE BEDS.

NEXT, THEY SAND THE SHELL'S OUTSIDE SURFACE,

FIRST WITH A ROUGH ABRASIVE BELT,

THEN WITH A FINE ONE.

THIS LEAVES THE METAL SHINY AND SILKY SMOOTH.

NOW THEY SAND THE INSIDE SURFACE BY HAND.

THEN THEY SPRAY IT WITH BRONZE-COLORED LACQUER

TO GIVE THE METAL AN EVEN COLOR AND PREVENT TARNISHING.

THEY TAPED OVER THE HOLES TO KEEP THE COLORED LACQUER

FROM HITTING THE OUTSIDE SURFACE.

NOW THEY REMOVE THE TAPE AND SPRAY THE OUTSIDE

WITH TRANSPARENT LACQUER,

WHICH ALLOWS THE NATURAL COLOR OF THE METAL TO SHOW THROUGH.

25 MINUTES IN AN OVEN HARDENS

THE LACQUER INTO A SUPER DURABLE FINISH.

THEN FINAL ASSEMBLY BEGINS, STARTING WITH THE TENSION LUGS,

THE FITTINGS THAT HOLD AND ADJUST THE TENSION

OF THE DRUM HEADS.

NEXT COMES THE ACTION STRAINER,

THE MECHANISM THE DRUMMER FLIPS UP OR DOWN

TO ACTIVATE AND DEACTIVATE THE SNARE SOUND.

THE TOP DRUM HEAD IS MADE OF A STRONG POLYESTER MATERIAL.

A CHROME-PLATED METAL HOOP WILL HOLD THE HEAD TO THE SHELL.

TO TUNE THE DRUM TO A HIGHER OR LOWER PITCH,

THE DRUMMER TIGHTENS OR LOOSENS THE SCREWS

TO INCREASE OR DECREASE TENSION.

DRUMHEAD TENSION DETERMINES PITCH.

THE BOTTOM DRUMHEAD IS MADE OF CLEAR POLYESTER FILM.

IT'S MUCH THINNER THAN THE TOP DRUMHEAD

TO ENABLE THE SNARE WIRE TO RESPOND FASTER.

THAT SNARE WIRE IS MADE OF

MULTIPLE STRANDS OF STAINLESS STEEL, BRASS, OR COPPER WIRE.

THEY STRETCH IT ACROSS THE BOTTOM HEAD,

LAYING EACH END ON A SNARE BED.

THEY ATTACH THE ENDS WITH NYLON CORDS TO THE ACTION STRAINER

ON ONE SIDE AND TO A PART CALLED THE BUTT END ON THE OTHER.

TO PLAY THE DRUM WITH THE SNARE SOUND,

THE DRUMMER SIMPLY PULLS UP

ON THE ACTION STRAINER'S HANDLE.

EVERY DRUM UNDERGOES A FINAL INSPECTION, THEN TUNING,

AND A THOROUGH PERFORMANCE TEST.

TALK ABOUT ENDING WITH A BANG.

--Captions by VITAC-- www.vitac.com

CAPTIONS PAID FOR BY DISCOVERY COMMUNICATIONS

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