Page 1: ...ASSEMBLING AND USING YOUR HIGH FIDELITY AMPLIFIER MODEL W 5M ...
Page 2: ...ost commonly used in Heath kits are 34 watt Higher wattage rated resistors when specified are progressively larger in physical size Small wire wound resistors 34 watt 1 or 2 watt may be color coded t ut the first band will be double width White RMA Black JAN CURRENT STANDARD CODE ignifkant Figure Class Multiplier Tolerance JAN A 1946 RMA CODE RMA 3 DOT OBSOLETE RATED 500 W V D C 20 TOL Multiplier ...
Page 3: ...THE HEATHKIT W 5M HIGH FIDELITY AMPLIFIER v H mSliSiSSS i V JUV i r iiiigsss f jf v jmmmrnmmtmmiimmm IIKi iiBiigBKiiilMlilgl 111111 ill ill i If iiiiil 1 r v r i r iM ...
Page 4: ...Page 2 THE HEATHKIT W 5M HIGH FIDELITY AMPLIFIER ...
Page 5: ...amplifier under carefully controlled conditions not to present the most favorable advertising information but in strict accordance with all generally accepted standard conditions These conditions are listed at the end of this specification Minor variations from these specifications may be encountered in kit assembled amplifiers Such factors as exact lead placement component variations and tube cha...
Page 6: ...istortion in the audio range This happens when low frequency trans ients such as turntable rumble line voltage surges or tuning thumps drive the amplifier into low frequency overload In the W 5M these transients cannot create any audible distortion and no hangover or breathing conditions are evident The curve in Figure 2 taken at 1 watt output and the 5 watt curve in Figure 1 represent aver age ro...
Page 7: ... the extremely high fidelity requirements HEATHKITW 5M POWER OUTPUT EQUIVALENT SINGLE FREQUENCY POWER IN WATTS PHASE SHIFT Figure 5 See Figure 6 below which is self explanatory 1CPS 10 CPS 00 CPS IKC 10 KC 100 KC IMC HEATHKITW 5M PHASE SHIFT Figure 6 A phase shift of 75 occurs at 1 2 cps It was impossible to locate the 90 leading point since it occurs below the pass band of the amplifier Note also...
Page 8: ...of 60 db below 100 modulation for AM or FM broadcast stations is recognized as acceptable by the Federal Communications Commission Most stations exceed this figure to some extent Modern LP recordings seldom exceed 40 db below average program level Broad cast quality tape recorders attain a noise level 60 db below full output The extremely low noise level of the W 5M exceeds these requirements comf...
Page 9: ...a far more im portant field is that of low frequency overload and instability for these defects are audible even to the untrained observer They are much more prevalent than is commonly believed in fact most people listening to a really wide range system with a stable bass response charac teristic are immediately impressed by the tremendous sense of freedom and drive in the repro duced sound Overlo...
Page 10: ... at any point on the wave form Its purpose was to determine if overload recovery was sufficient to faithfully present a short transient immediately following overload The composite test signal is shown in oscillo gram F Again remember that the upper trace is the input signal the lower trace is the output of the amplifier In order to show the critical portion of the cycle more clearly oscillogram G...
Page 11: ...equirements Heavy mar proof rubber mounting feet to protect mounting surface Mounting bolts and T nuts furnished can be mounted on any surface up to 7 8 thick POWER REQUIREMENTS 105 125 volts 50 60 cycles 140 watts WEIGHT 26 5 lbs net TEST CONDITIONS Output Impedance Dummy load 16 43 ft cold resistive Line Voltage 117 volts 60 cycles regulated Accessories All measurements made while the amplifier ...
Page 12: ...ly coupled to the grid of the second half of the tube Phase splitting or signal inversion is accomplished in the second half of the first 12AU7 which is a split load type of inverter Signal at the cathode of this stage follows the grid while the plate voltage will swing in the opposite direction Coupling to the grids of the second 12AU7 push pull driver stage is through 1 Ltfd capacitors one conne...
Page 13: ... is 470 volts Special single section condensers could have been used but it would be impossible to employ them and provide the safety factor obtained by using series units The amplifier cover is another advantage in that the appearance is improved and small children are protected from severe burns since they cannot touch the output tubes and rectifier which run quite hot NOTES ON ASSEMBLY AND WIRI...
Page 14: ...kets are mounted inside the chassis except for miniature 9 pin shielded sockets which are mounted on top The insulated filter condenser mounting wafers are mounted on top of the chassis Other details of construction are included where pertinent in the instructions Place the chassis with the open side up in front of you on your workbench Be sure that the apron with the holes in it is nearest you Se...
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Page 16: ... containing red red yellow and yellow wires the other containing black green and green yellow wires Pass the red red yellow and yellow wires through grommet S and the other group through grommet T Secure the transformer to the chassis using six 8 32 screws lockwashers and nuts CONTROL SOLDER LUG OR LOCKWASHER _ PANEL OR CHASSIS FLAT WASHER NUT CONTROL MOUNTING Figure 10 Identify the filter choke t...
Page 17: ...n they need to be to make the indicated connections In these cases the excess leads should be cut off before the part is added to the chassis In general the leads should be just long enough to reach their terminating points Not only does this make the wiring much neater but in many instances the excessively long leads will actually interfere with proper operation of the instrument The pictorials i...
Page 18: ...Page 16 PICTORIAL 1 ...
Page 19: ... grommet M on the output transformer along the bend in the chassis and to terminal strip P Cut the lead to length to reach PI strip tin and con nect the wire to Pi NS Be sure that this lead is dressed into the bend of the chassis as shown in Pictorial 1 X Twist together the blue and blue white wires coming through grommet Mand dress them to ward socket V4 Cut the blue wire to length to reach V4 3 ...
Page 20: ...VI 5 NS to VI 4 S Now solder VI 5 T Connect a wire from socket AA7 S to AC outlet DD2 S Connect a wire from AA8 S to AC outlet CC1 NS X Connect a short bare wire from CC1 NS to DDl S f Using bare wire and sleeving connect CC2 NS to fuse holder Figure 14 EEl S Connect a wire from AA6 S to EE2 S Connect a wire from AA5 S to V5 5 NS Dress this wire under the Spirashield and the green twisted pair as ...
Page 21: ... a 22 KS2 1 2 watt resistor small body red red orange from V4 5 S to terminal strip F2 NS Dress this resistor directly over the body of the 270 f2 resistor Connect a 22KS2 1 2 watt resistor from V3 5 S to terminal strip El NS Dress this res istor over the body of the 270 Q resistor f Connect a 330 12 7 watt resistor large ceramic body from V3 1 NS to V4 1 NS Dress the body of the resistor against ...
Page 22: ...ng f Connect a 1 pfd 400 volt condenser from V2 1 S to terminal strip El S 4 Connect a 1 jufd 400 volt condenser from V2 6 S use sleeving to terminal strip F2 S Using bare wire and sleeving connect a jumper from VI 1 NS to VI 7 S j Select one of the 22Kfi 1 2 watt matched pair resistors small body red red orange Cut one lead to a length of 1 2 and connect this lead to terminal strip C3 S Dress the...
Page 23: ...Clip off any excess wire beyond B and N The wire will be referred to as a ground bus Cut a 2 1 2 length of the heavy bare wire Make a square bend 3 8 from one end Connect this end to B3 S Connect the other end to phono socket Y2 S Use the balance of the heavy bare wire to make the following connections s5 Slip a 1 5 8 length of sleeving over one end of the wire Form a small hook at the end and ins...
Page 24: ...g 6 32 lockwashers and nuts Referring to Figure 16 attach the plastic name plate and escutcheon to the cover screen using the speed nuts provided A suggested location is given in Figure 16 Any of the hor izontal slots in the cover will accept the name plate pins if some other location is pre ferred Figure 16 Page 22 ...
Page 25: ... possible noise figure Pins 6 and 7 of the power socket should be jumpered with a switch or wire to apply power to the amplifier if a preamplifier other than a Heathkit is used When a preamplifier with a filament hum balance control such as the Heathkit WA P2 is used with the W 5M the green yellow transformer wire should be left disconnected and taped up at the end to avoid short circuits Dress th...
Page 26: ...w should be evident ineachl2AU7 If a preamplifier is powered by the W 5M main amplifier the filaments of the preamp should also be lit If the filaments fail to light check the steps outlined under In Case of Difficulty Plug the 5R4GY rectifier in socket V5 and watch it carefully If the plates begin to show a red color or a purple glow appears inside the tube elements shut the amplifier off immed i...
Page 27: ...h voltage is present throughout the circuit and due care should be exercised This should cause a hum level to be evident in the speaker if the circuit from this point is nor mal Work on forward in the circuit touching terminals V3 5 V2 6 V2 7 V2 1 V2 2 Vl 8 VI 6 VI 7 VI 1 and VI 2 The hum level should increase somewhat as you work back toward the amplifier input At some point in the amplifier the ...
Page 28: ...it might be advisable to separate the two wires to reduce capacity For the best frequency response and stability characteristics it is recommended that the preamplifier be connected to the main amplifier with leads just long enough to satisfactorily meet the requirements of the individual installation Excessively long audio cables will attenuate high frequencies and the high capacity may cause osc...
Page 29: ... of installation Large rubber feet are used so that the unit can be placed anywhere without danger of marring furniture and it will not slide about even if not bolted down For permanent installations the unit can be fastened down with the bolts and T nuts furnished using the furnished template to cut the two necessary holes Use the large fiber washers under the bolt heads to prevent marring the ch...
Page 30: ...ed to the switched outlet should not exceed 150 watts otherwise the fuse will blow We suggest that the AC NORMAL outlet be used for record changers equipped with automatic shut off switches or other accessories for which independent switching is desired The AC SWITCHED outlet will be convenient for tuners tape recorders etc CAUTION Do not use the switched outlet for powering professional type turn...
Page 31: ...ency power is fed to the speaker it begins to overheat and fails This may take place even though the oscillation occurs only intermittently and under continuous oscillation even the finest high frequency drivers fail in less than one minute The Tweeter Saver will prevent these oscillations even though no speaker is connected A relatively small load resistor rated at only 1 2 watt can be used safel...
Page 32: ...builder according to information which will be much more readily available from some local source SHIPPING INSTRUCTIONS Before returning a unit for service be sure that all parts are securely mounted Attach a tag to the instrument giving name address and trouble experienced Pack in a rugged container preferably wood using at least three inches of shredded newspaper or excelsior on all sides DO NOT...
Page 33: ... 23 28 1 1 jifd 200 volt Hardware 23 53 3 1 jifd 400 volt 250 2 4 3 48 x 1 4 screw 23 66 2 1 jLtfd 400 volt 250 8 6 6 sheet metal screw 25 10 1 20 20 20 jLtfd 450 volt elec 250 9 31 6 32 x 3 8 screw 25 16 2 20 jifd 350 volt elec 250 18 14 8 32 x 3 8 screw 25 28 2 100 jifd 50 volt elec 250 48 4 6 32 x 1 2 screw 25 36 2 40 jifd 450 volt elec 250 52 8 4 40 x 1 4 pan head screw 25 37 1 40 40 jLtfd 450...
Page 34: ... BALANCE BASS BAL VOLTAGE ...
Page 35: ...nsulation from the end of hookup wT ire it is seldom necessary to expose more than a quarter inch of the wire Excessive insulation removal may cause a short circuit condition in respect to nearby wiring or terminals In some instances transformer leads of solid copper will have a brown baked enamel coating After the trans former leads have been trimmed to a suitable length it is necessary to scrape...
Page 36: ...HEATH COMPANY BENTON HARBOR MICHIGAN 4 15 55 ...
