Download DYNACO PAS-4 Owner`s manual
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PAS-4 Vacuum Tube Preamplifier Owner's Manual VACUUM TUBE PREAMPLIFIER R PAS-4 CD VIDEO AUX SOURCE TUNER 2 to 1 SOURCE TAPE 1 1 to 2 TAPE 2 LEFT RIGHT EPL PHONO IN INPUT TAPE DUBBING TAPE MONITOR BALANCE PAS-4 Vacuum Tube Preamplifier MONO IN VOLUME POWER Contents Introduction ...................................................................................... 3 Rear Panel Inputs and Outputs ....................................................... 4 Fuse ................................................................................................. 4 Operation ......................................................................................... 5 Tube Replacement .......................................................................... 7 Alternate Tube Types ...................................................................... 8 Minimizing Noise in the System ...................................................... 9 Warranty .......................................................................................... 10 PAS-4 Specifications ....................................................................... 11 Schematics ...................................................................................... 12 PC Board Parts List ......................................................................... 14 Please read this manual thoroughly before operating your new PAS-4. 2 Introduction Congratulations on your purchase of the Dynaco PAS-4 preamp. This preamplifier was designed to provide the highest combination of quality and value available, which is the Dynaco tradition. Only very high quality components have been used in manufacturing the PAS-4. Examples of this are the low noise metal-film resistors, polypropylene film capacitors, and selected (tested) vacuum tubes. Likewise, the high quality rotary switches and potentiometers provide better performance and reliability than what is found in most other audio equipment. Unique to this modern PAS-4 vacuum tube design is its power supply buffering circuitry - found in no other preamp of this class. We have included a separate buffer circuit for each of its six tubes, allowing each amplification stage to function more independently, (as if each has its own separate power supply). This contributes significantly to the extraordinary sonic clarity of the PAS-4. The PAS-4 contains a true state-of-the-art phono preamp section. It provides a front panel switched "external processing loop" for use with a graphic equalizer or other signal processing equipment. It also includes full provisions for tape dubbing between two tape decks ("1 to 2" and "2 to 1"). You will find the PAS-4 to sound better than the large majority of other preamplifiers - both solid state and vacuum tube designs - regardless of price. Its flexibility and full-featured styling is without parallel in affordable preamps. Your PAS-4 was designed and built entirely in the USA. We are proud to offer this outstanding preamplifier to discerning audiophiles the world over. Dynaco Engineering Group 3 Rear Panel Inputs and Outputs Inputs - Phono These inputs will accommodate "moving magnet" or high output "moving coil" cartridges which have output levels of 1.0mV or higher. In the lower right hand corner of the rear panel is the preamp's chassis ground terminal. This thumbscrew is provided for attaching the separate ground wire often provided on turntables. (see Minimizing System Noise on page 11) Inputs - Tuner, CD, Video, Aux., Tape 1 & 2 These inputs receive standard line (high level) input signals from other equipment. The Tape Inputs of the PAS-4 connect to Line Outputs (Play) on tape decks. Tape Outputs Signals sent to these outputs are at line level. (Phono signals are first amplified and equalized). Tape Outputs are unaffected by external processing circuits, the Mono switch, the Volume control, or the Balance control. The preamp's Tape Outputs connect to the tape deck(s) Line (Record) Inputs . Preamplifier Main Outputs Two pairs of outputs are provided for your power amplifier(s). The two left channel RCA jacks are connected directly together inside of the PAS-4, as is the right channel pair. EQ (External Processing Loop) "EQ Out" are line level outputs which can be connected to the inputs of an external signal processor such as an equalizer, time delay, or noise reduction unit. "EQ In" are for line level inputs coming from the signal processor outputs. FUSE AC Line Fuse: 2 Amp Fast-Blow - 100 or 115 VAC 1 Amp Fast-Blow - 230 VAC 120 PUSH TAB TO RELEASE FUSE HOLDER To remove the AC line fuse, use a small screwdriver to push forward the tab near the center of the Power Entry Module. Always remove the power cord when accessing the AC line fuse. 4 Operation Turn-On Delay and Visual Indicator When you turn on the PAS-4, the lamp above the PWR (power) switch glows GREEN and a timer circuit is evoked which keeps the preamp outputs at zero volts during the warm-up period. This 45-second warm-up period allows the tube filaments to fully heat, the high-voltage section of the power supply to reach full potential, and for the preamp output circuitry to settle, (avoiding loud turn-on "thumps"). When warm-up is finished, the lamp turns to RED and the preamp outputs are operative. When you turn off the PAS-4, the outputs immediately clamp to zero volts. Turning the preamp back on at this point will require, again, waiting through the warm-up period. Input Selection Your choice of a signal source is indicated by the INPUT switch position you select. This signal source is what you will hear. It is also sent to the Tape (recording) Outputs and the EQ Outputs, (as long as the TAPE MONITOR and TAPE DUBBING switches are both set to SOURCE). Tape Deck Selection - Listening You may bypass the INPUT switch selection by using the TAPE MONITOR switch, in which case the signal from the selected tape deck is what you will hear and what is sent to the EQ Out jacks. When the TAPE MONITOR switch is turned to Tape 1 or Tape 2, what you hear is the signal from the tape deck playback head, not the original source signal (which is being recorded onto tape via the tape deck record head). This feature allows direct comparison of the signal source with taped replica without affecting the recording process. (If a tape deck does not have separate record and playback heads, then the signal you hear when using the TAPE MONITOR switch is the same signal being sent to the tape deck to be recorded.) The following controls affect all signals which are heard through the speakers. They have no effect, however, on signals being recorded at the Tape Outputs. EQ Switch Pushing IN the EQ switch inserts a signal processing device into the preamplifier signal path (if such a device is connected to the EQ Inputs and Outputs). This part of the signal path is then called the External Processor Loop (EPL). Such devices include equalizers, time delays or ambiance simulators, expanders, compressors, and noise reduction systems. When the EQ switch is in the OUT position, any equipment plugged into the EQ inputs is effectively removed from the preamplifier signal path. Therefore, an unpowered device connected to the EQ Inputs and Outputs will not deteriorate the PAS-4's performance (which can happen with some tape decks, as mentioned above). Note: The EQ inputs can also be used as a second set of Auxiliary Inputs - (for a second tuner, second CD player, etc.) Therefore, the EQ switch itself can also function as an additional input selector. Mono Switch When this button is IN, left and right channel information is combined and the composite signal is fed to both left and right outputs. In this mode the sound image should appear to be centrally located between the loudspeakers. This switch is useful when listening to monophonic program material. It cancels the unwanted vertical phonograph modulations which are heard as noise from monaural records. 5 Balance Control This adjusts the proportion of left and right channel signals going to the preamp's line level amplification stage (and therefore to the preamp's main outputs). Only the left channel signal will be heard with the Balance Control turned fully counter-clockwise, and only the right channel signal with full clockwise rotation. The function of the Balance Control is to compensate for unbalanced left and right channel signal levels (from phonograph records, for instance) or to compensate for non-symmetrical room acoustics (from furniture, wall reflections, etc.). Tape Deck Selection - Recording The TAPE DUBBING switch determines which signals are sent to the tape decks for recording purposes. If the TAPE DUBBING switch is set to SOURCE, both tape decks receive the same signal - the one indicated by the position of the INPUT switch. A copy of a tape can be made when the TAPE DUBBING switch is set to either ‘2 to 1’ or ‘1 to 2’. (When this is done, the signal source selected by the INPUT switch is disconnected from both tape decks.) When the TAPE DUBBING switch is set to ‘2 to 1’, the output of tape deck #2 goes to the input of tape deck #1 to be recorded. When the TAPE DUBBING switch is set to "1 to 2", the output of tape deck #1 goes to the input of tape deck #2 to be recorded. The TAPE MONITOR switch can be used to listen to the "source" tape deck (the original recording) or the "target" tape deck (the dubbed recording) while tape dubbing is being done. However, if the TAPE MONITOR switch is set to SOURCE, one can listen to any music signal selected with the INPUT switch while tape dubbing is in progress. ___________________________________________ Note: Some older tape decks which do not have high impedance input circuitry can present non-linear loads to a preamp's Tape Outputs even when the tape decks are turned off. This can be a problem because the Tape Outputs are usually connected to which ever signal source has been selected by the INPUT switch. This “always present” non-linear load can degrade performance on most preamps. With the PAS-4 there is a solution to the use of lower input impedance tape decks. Simply keep the TAPE DUBBING switch positioned to ‘1 to 2’ or ‘2 to 1’ when the deck is not in use. This disconnects the signal selected by the INPUT switch from both tape decks, as mentioned previously. 6 Tube Replacement CAUTION: Before replacing tubes on your PAS-4 ensure the AC power cord is un- plugged from its AC (wall) outlet (or that the AC power cord is unplugged from the back of the unit) and wait for three minutes to allow the high voltage power supply to discharge. Gloves may be worn when changing tubes. Never touch live circuit elements in vacuum tube equipment because lethal voltages are present when these are turned on. The tubes in your PAS-4 could provide 5,000 to 10,000 hours of use. We recomend that these tubes be replaced after no more than 3,000 hours of use to avoid the slightly "muffled" sound or slight bass "rolloff" which can begin to occur with old tubes. Microphonics (various "pinging" or "howling" sounds) is due to a tube being overly sensitive to physical vibrations. To avoid it, do not operate vacuum tube equipment on top of vibrating surfaces (such as loudspeakers). But if a tube is so sensitive that just having the preamplfier turned on causes the microphonic sounds, the tube will have to be replaced. It can happen that a tube becomes microphonic with age or that it is only microphonic before it warms up (or only after it warms up). The most common type of problem in tube preamplifiers is excessive noise caused by a worn or faulty tube. The characteristics of this noise can vary a great deal. If a noise problem occurs with your PAS-4, 99% of the time it will be due to a faulty tube The most likely source of tube noise in the PAS-4 is the phono section first stage tubes V1 (left channel) or V4 (right channel). Less likely, but to be suspected next, would be the phono stage second stage tubes V2 (left) or V5 (right). If the undesirable noise increases as you turn up the volume control, the faulty tube is likely to be one of the phono section tubes. The line stage tubes are V3 (left) and V6 (right). (Refer to the tube numbers printed adjacent to pin #1 of each tube on the printed circuit board.) Note: When removing a tube, grasp the tube socket with one hand and the tube with the other hand. Move the tube (slightly) from side to side while pulling outward. The most certain method for confirming a faulty tube is by substitution of a known good tube. An easy way to determine if a tube in any particular position is causing un-desirable noise is to swap the suspected tube with its counterpart in the opposite channel. If the noise jumps to the other channel, the tube you suspected is indeed faulty. 7 Alternate Tube Types It is true that vacuum tubes made by different manufactures can actually sound different. The amount and type of sonic differences can be subtle or fairly obvious to a discerning listener. Also, tube reliability and longevity often varies according to manufacturer. Vacuum tube manufacturers are still introducing new versions of older tube designs. These new designs are commonly labeled with partly or wholly new part numbers. Furthermore, different vacuum tube manufacturers often use different part numbers for their own versions of “equivalent” tubes. Distributors sometimes substitute tubes from different manufacturers and/or substitute tubes with alternate part numbers without informing their customers first. Some audiophiles feel strongly about which manufacturer and/or particular version of vacuum tube to use for specific applications. The tubes installed on your new PAS-4 have been selected to provide the best sound and long life. As of this writing, vacuum tubes are still produced by manufacturers in Germany (Siemens), Russia (Sovtek), Czechoslovakia (Telsa), China (Sino), Yugoslavia (EI), and in England. Your dealer can recommend U.S. tube distributors, if needed. Alternate tube part numbers which can be used on the PAS-4: Designator Common Part Numbers Alternate Part Numbers V1, V4 12AX7 ECC83 V2, V3, V5, V6 6DJ8 ECC88, 6922, 7308 If tube replacement becomes necessary, Dynaco can supply you with new vacuum tubes and/or a list of specifically recommended tubes for the PAS-4. _______________________________________________________________________ Note: Because it is possible for oxidation to build up on vacuum tube pins, it is a good idea to remove and clean them with a small (brass bristle) wire brush once a year. At this time it is also recommended to clean the tube pins with contact cleaner. Contact cleaner leaves a thin coating on the pins which helps prevent oxidation. The contact cleaner can either be sprayed directly onto the tube pins (don’t get any on the glass part of the tube) or can be sprayed on a clean cloth which is then used to wipe the tube pins. 8 Minimizing Noise in the System Hum is caused by amplification of the 50 or 60 Hz AC power line signal that is transmitted via the magnetic fields around power transformers and power cables. RF interference usually comes from inadequate shielding of cables or components. If any of these types of noises are encountered, one or more of the following pointers concerning proper component positioning and grounding may be of use: ➣ Ensure that each system component, especially the preamplifier, is located far enough away from the other components so that they will not pick up hum from them, and that the AC power cables are not in close proximity to audio cables. ➣ Ensure that all audio cables are securely pushed into their respective jacks. A faulty audio cable, although rare, can be a source of hum if its outer shield is broken or disconnected from an RCA plug at one end of the cable. ➣ The best “system grounding scheme” is to have your preamplifier well grounded to an earth ground point and function as the system's main ground reference. Other system components are then quite adequately grounded by being connected to the preamplifier’s ground via their audio cables. Using this grounding scheme can be as simple as just plugging the preamplifier’s power cable into a three prong AC outlet. However, if the AC outlet itself does not provide a really "good" ground, the preamplifier power cable can be plugged into a three-to-two prong adapter and a wire can be run from the tab on the adapter to the nearest cold water pipe. ➣ Another solution to AC power cable "ground loop" hum problems is to plug the AC power cables from all of the system components into a common "socket strip" (available from most hardware stores). ➣ If RF noise (usually an AM radio station or CB transmission) is a problem in your area, an AC power filter can be purchased into which some or all of your system power cords can be plugged. This is done if the RF is coming in through the building's AC wiring. However, if RF gets into the system via your turntable, you may have to use tonearm cables with better shielding. (This is tested by unplugging the turntable from the system and putting "shorting plugs" in the preamplifier’s phono inputs before listening again.) RF noise is sometimes eliminated by simply moving the turntable or other components to another location in the room. ➣ Hum from a turntable is usually traced to an adjacent power transformer or a missing or improper ground. Check to see that the turntable motor is grounded via a wire to the preamplifier’s grounding post - (or try removing this wire from the ground post if it is already connected there). 9 Warranty For three years from the date of purchase (one1 year for tubes) Dynaco will repair, for the original owner, any defect in materials or workmanship that occurs in normal use, without charge for parts or labor. It is the owner's responsibility to provide transportation to the authorized Dynaco service representative who will perform warranty service, and to present proof of purchase in the form of a dated sales slip when requesting service. Excluded from this warranty is damage that results from abuse, misuse, accidents, shipping, repairs or modification by anyone other than an authorized Dynaco service representative. This warranty is void if the serial number has been removed or defaced. This warranty gives you specific legal rights, and you may also have other rights - which vary from state to state. If service is required, contact the dealer from whom you purchased the amplifier. If that is not possible, write Dynaco, giving us: ✓ Your name and address ✓ Make and model of your amplifier ✓ The amplifier’s serial number ✓ When and where you purchased it (copy of sales slip) ✓ Description of the problem ✓ Whether you have the original carton and fillers or need new ones DYNACO strongly recommends using only its performance checked pre-tested vacuum tubes. Each tube is guaranteed to perform properly in its intended application for ONE YEAR. Orders for tubes may be paid for by personal check or money order. Please also include $4.00 for shipping and handling. Dynaco A Division of Panor Corporation 125 Cabot Court Hauppauge, New York 11788 (516) 434-1200 (516) 434-1457 FAX 10 PAS-4 Specifications Phono Section GAIN: 40 dB RIAA ACCURACY: +/- .5 dB from 20 Hz to 20 kHz PHONO OVERLOAD: 500mV RMS @ 1kHz MAXIMUM OUTPUT CAPABILITY: 60V RMS @ 1kHz THD: INPUT IMPEDANCE: 50V RMS @ 20kHz (for 1% THD) less than .025% @ 2V RMS Output 47k shunted by 10pF TAPE OUTPUT IMPEDANCE: 2k NOISE: -86 dB below 10mV RMS Input ABSOLUTE PHASE: Non-Inverting TUBE COMPLEMENT: 2ea 6DJ8 (6922); 2ea 12AX7 (ECC83) Line Section GAIN: 18.5 dB FREQUENCY RESPONSE: MAXIMUM OUTPUT: 2 Hz to 150 kHz (nominal) (-3 dB, 20 k ohm load) 40V RMS (for 1% THD) THD: .025% @ 2V RMS Output INPUT IMPEDANCE: 25k nominal (all inputs) OUTPUT IMPEDANCE: 40 ohms NOISE: -90 dB below 2V RMS Output ABSOLUTE PHASE: Inverting SLEW RATE: 40 V/µs TUBE COMPLEMENT: 2ea 6DJ8 (6922) Electrical / Mechanical POWER REQUIREMENTS: 100, 115, or 230 VAC @ 50/60 Hz POWER CONSUMPTION: 45 Watts DIMENSIONS: 17" Wide, 3.75" High, 12" Deep NET WEIGHT: 12 lbs. SHIPPING WEIGHT: 14 lbs. 11 12 EQ IN EQ OUT TAPE 2 IN TAPE 2 OUT TAPE 1 IN TAPE 1 OUT AUX VIDEO CD TUNER PHONO RIGHT INPUTS EQ IN EQ OUT TAPE 2 IN TAPE 2 OUT TAPE 1 IN TAPE 1 OUT AUX VIDEO CD TUNER PHONO LEFT INPUTS 2K R102 2K R101 2K R2 2K R1 8 9 8 7 9 10 1 2 3 2 3 4 16 SW4A SW2A 22 12 11 10 SW4B SW2B TAPE DUBBING 19 SW1B INPUT SELECTOR ACTIVE INACTIVE EQUALIZER 19 7 11 5 6 4 TAPE DUBBING 13 SW1A INPUT SELECTOR ACTIVE INACTIVE EQUALIZER 13 1 5 8 2 7 9 1 3 19 SW3B TAPE MONITOR 13 SW3A TAPE MONITOR R103 47K FB2 R3 47K FB1 C2 22pF C102 2 10pF 1 C101 22pF 2 10pF 1 C1 3 6 8 R104 1.37K 8 249K R106 -3.3V R7 2M 249K R6 7 -3.3V R107 V4 12AX7 2M .1uF 400V C103 7 V1 12AX7 .1uF 400V C3 R4 1.37K R105 287K 1W +300V D 3 6 R5 287K 1W +300V A R110 165K C105 440pF R108 6.49K C104 220pF 301 R109 2 V5A 6DJ8 C6 1 7 3 3 1500pF C106 1 7 6 6 +300V E 1500pF V5B 6DJ8 2 R111 301 R10 165K C5 440pF R8 6.49K 220pF C4 301 R9 V2A 6DJ8 R11 301 V2B 6DJ8 +300V B 9 R112 249 8 9 R12 249 8 R113 499K 3.3uF 400V C107 R13 499K 3.3uF 400V C7 R18 P1B 50K P2B 50K VOLUME MONO P2A 50K 3W RESISTORS ARE 5%, METAL OXIDE 24.9K R119 BALANCE 24.9K R19 BALANCE 1/2W AND 1W RESISTORS ARE 1%, METAL FILM 5.6K R118 STEREO SW5 5.6K P1A 50K VOLUME V6B 6DJ8 2 REV B 301 R120 2 V6A 6DJ8 C108 .1uF 400V R123 301 301 R20 V3A 6DJ8 C8 .1uF 400V R23 301 V3B 6DJ8 6 C109 3.3uF 400V C9 9 R126 15K 3W 3.3uF R125 400V 221 8 9 R26 15K 3W R25 221 8 R127 499K 140 R128 R27 499K 140 R28 8 12 19 JULY 94 PAGE 1 OF 2 K1-A N.O. DWG# 00501 K1-B 2 1 RIGHT OUTPUTS N.O. N.C. 2 1 LEFT OUTPUTS 10 N.C. 7 4 6 PAS-4 PREAMPLIFIER 301K R122 R121 221 3 1 2M R124 7 +300V F 301K R22 R21 221 3 1 2M R24 7 6 +300V C 13 1 2 4 G L N 2A /100V 2A /115V 1A / 230V F1 FAST BLOW POWER ENTRY MODULE C204 C203 R201 100 C201 .01uF 1.4KV BLK 100V 0.0V .01uF 1.4KV (x 2) AC POWER SW7A BRN WHT 115V 230V BRN/WHT 50/60 Hz 100/115/230 VAC T1 GRN GRN R206 30K R205 20K RED RED D4 D3 C206 33uF 450V 470 3W R202 C219 4700uF 25V FWB1 600V 35A C207 1000uF 6.3V I 19.5V @ 1A R204 1M 1W R203 332K O C220 22uF 25V G U1 7812 -3.3V SOURCE D5 THRU D11 C205 33uF 450V D1 D2 421V @ 45mA C221 470uF 25V .47 ohm 3W R216 C208 1.0uF 400V 5.1M R207A SW7B V6 RIGHT LINE 6DJ8 4 5 4 5 TIMER V3 LEFT LINE 6DJ8 C209 1.0uF 400V C210 1.0uF 400V 5.1M R207B ON OFF C222 10uF 25V R217 4.02M C211 1.0uF 400V R210 470 C213 .22uF 400V ZD1 12V G Q1 6 2 U2 4 1 I 16 1 G O G Q2 IRF 830 S D GREEN RED ZD4 200V 5W (1) R219 470 R218 470 R212 470 I C215 .22uF 400V ZD5 12V G Q3 O +300V C ZD6 200V 5W C223 22uF 25V G U3 7812 S D Q1 - Q6 = IRF 830 ZD2, 4, 6, 8, 10, 12 = 1N5388B ZD1, 3, 5, 7, 9, 11 = 1N5242B D1 - D12 = 1N4007 +300V B D13 BI-COLOR LED (2) G D S K1 C214 .22uF 400V ZD3 12V FRONT VIEWS 3 D12 7812 8 R211 470 C212 22uF 250V +300V A ZD2 200V 5W 555 R208 1M R209 1M S D G Q4 C224 470uF 25V C216 .22uF 400V ZD7 12V .47 ohm 3W R220 R213 470 ZD8 200V 5W V2 LEFT PHONO 6DJ8 B V1 LEFT PHONO 12AX7 R214 470 REV 5 4 5 4 +300V D V5 RIGHT PHONO 6DJ8 S D 5 9 4 R215 470 +300V E ZD10 200V 5W Q6 C218 1uF 400V ZD11 12V G S D PAGE 2 OF 2 +300V F ZD12 200V 5W DWG# 00501 PAS-4 PREAMPLIFIER V4 RIGHT PHONO 12AX7 S D 19 JULY 94 5 9 4 C217 .22uF 400V ZD9 12V G Q5 PAS-4 PC Board Parts List DESCRIPTION DESIGNATORS Resistors 100 ohm, 1/2W, metal film R201 140 ohm, 1/2W, metal film R28, 128 221 ohm, 1/2W, metal film R21, 25, 121, 125 249 ohm, 1/2W, metal film R12, 112 301 ohm, 1/2W, metal film R9, 11, 20, 23, 109, 111, 120, 123 470 ohm, 1/2W, metal film R210, 211, 212, 213, 214, 215, 218, 219 1.37K, 1/2W, metal film R4, 104 2.0K, 1/2W, metal film R1, 2, 101, 102 5.6K, 1/2W, metal film R18, 118 6.49K, 1/2W, metal film R8, 108 20K, 1/2W, metal film R205 24.9K, 1/2W, metal film R19, 119 30K, 1/2W, metal film R206 47K, 1/2W, metal film R3, 103 165K, 1/2W, metal film R10, 110 249K, 1/2W, metal film R6, 106 301K, 1/2W, metal film R22, 122 332K, 1/2W, metal film R203 499K, 1/2W, metal film R13, 27, 113, 127 1M, 1/2W, metal film R208, 210 2M, 1/2W, metal film R7, 24, 107, 124 4.02M, 1/2W, metal film R217 5.1M, 1/2W, metal film R207A, 207B 287K, 1W, metal film R5, 105 1M, 1W, metal film R204 .47 ohm, 3W, metal oxide R216, 220 470 ohm, 3W, metal oxide R202 15K, 3W, metal oxide R26, 126 Capacitors 10pF, 630V, polystyrene C1, 101 22pF, 630V, polystyrene C2, 102 220pF, 400V, polypropylene 5% C4, 5A, 5B, 104, 105A, 105B 1500pF, 400V, polypropylene 5% C6, 106 .01uF, 1.4 kV, ceramic disc C201, 203, 204 .1uF, 400V, polypropylene C3, 8, 103, 108 .22uF, 400V, polypropylene C213, 214, 215, 216, 217, 218 1.0uF, 400V, polypropylene C208, 209, 210, 211 3.3uF, 400V, polypropylene C7, 9, 107, 109 14 PAS-4 PC Board Parts List (cont.) DESCRIPTION DESIGNATORS Capacitors (cont.) 10.uF, 25V, alum electrolytic C222 22uF, 25V, alum electrolytic C220, 223 22uF, 250V, alum electrolytic C212 33uF, 450V, alum electrolytic C205, 206 470uF, 25V, alum electrolytic C221, 224 1000uF, 6.3V, alum electrolytic C207 4700uF, 25V, alum electrolytic C219 Semiconductors 1N4007 (1A, 1kV) D1 thru D12 1N5242B (12V, 1/2w Zener) ZD1, 3, 5, 7, 9, 11 1N5388 (200V, 5w Zener) ZD2, 4, 6, 8, 10, 12 3506 (35A, 600 PIV Bridge Rectifier) FWB1 7812 (Regulator) U1 ,3 555 (Timer) U2 LED, Bi-Color, (red/green) D13 IRF 830 (N-Channel FET) Q1 thru Q6 Tubes 12AX7 (ECC83) V1, 4 6DJ8 (6922) V2, 3, 5, 6 Switches Switch, pushbutton, 2 pole / 2 position SW7 (AC power) Switch, pushbutton, dual 2 pole / 2 position SW4/ 5 (stereo/mono, EQ) Switch, rotary, 2 pole / 5 position P/N 333125 SW1 (input selector) Switch, rotary, 4 pole / 3 position P/N 333124 SW2 (tape dubbing) Switch, rotary, 2 pole / 3 position P/N 333124 SW3 (tape monitor) Misc. 50K, dual VOLUME potentiometer P1 50K, dual BALANCE potentiometer P2 Relay (DPDT) P/N DS2YE-S-DC12V K1 Ferrite Beads FB1, 2 Fuse, fast-blow, 2A for 100 or 115VAC - 1A for 230VAC F1 RCA Jack Assembly - 2x2 P/N RJ-PCM-204 JA1, 2, 3, 4, 5, 7 RCA Jack Assembly - 1x2 P/N RJ-PCM-102 JA6 PC Board 17-0382-B 15