Parts Sources for the Leach Amp

Parts Sources for the Leach Amp This list of parts with sources and prices was prepared by Craig Truesdell and Jim Musial. Craig built a 6 channel version of
the amplifier in the fall of 1995. Jim built a 2 channel version in the spring of 2006. In many cases, the parts can be
bought cheaper than the prices listed here. The abbreviations used for the sources are as follows:
DK -    DigiKey ACK -    Ack Radio, 554 Deering Road NW, Atlanta, GA Inside Atlanta: 404-351-6340 Outside Atlanta: 800-282-7954 MCM -    MCM Electronics NEW -    Newark Electronics MARK -    Mark V Electronics, Inc     http://www.markvelectronics.com/store     8019 E. Slauson Avenue Montebello, CA 90640 http://www.markvelectronics.comTel : 800-423-FIVE (orders outside Canada)
800-521-MARK (orders in Canada) 213-888-8988 (catalog/info) Fax: 213-888-6868 ACE - Ace Hardware
    Must Quan.    Buy    Source    Part Description        $/Unit    $Total _____    ____    ______    ________________        ______    ______
Transistors 12    12    DK    2N5210 NPN            0.36     4.32 10    10    DK    2N5087 PNP            0.48     4.80 4     5    MCM    2N3439 NPN            1.85     9.25 4     4    MCM    2N5415 PNP            2.13     10.65 2     2    MCM    MJE15030 NPN            1.94     3.88 2     2    MCM    MJE15031 PNP            2.23     4.46 4     4    MCM    MJ15003 NPN            4.91     19.64 4     4    MCM    MJ15004 PNP            4.91     19.64                                 _______ Total                                $76.64
Alternates for the MJE15030 and MJE15031 2     2    ACK    2N6474 NPN            1.15     2.30 2     2    NEW    2N6476 PNP            1.32     2.64
Diodes 12    20    DK    1N4004 Diode                 1.44 12    20    DK    1N4148 Diode                 1.28                                 ______ Total                                $ 2.72
Capacitors 2     2    ACK    SM15J391 390 pF mica        1.01     2.02 2     2    ACK    SM15J181 180 pF mica        0.65     1.30 2     2    ACK    SM15J470 47 pF mica        0.48     .96 4     4    ACK    SM15J100 10 pF mica        0.48     1.92 2 2    ACK Mallory CGS103U075V3C             10,000 uF 75V         19.40     38.80 8    10    DK    P4525 0.1 uF 50V             1.65 12    12    DK    P6283 100 uF 63V             2.77 2     2    DK    P1120 220 uF 16V        1.03     2.06 4    10    DK    P4513 0.01 uF 50V             1.20 14    20    DK    P4725 0.1 uF 100V             4.38 1     1    DK    E2104 0.1 uF 250V         .25     .25                                 ______ Total                                $57.31
Resistors, 1/4 Watt unless otherwise specified. 2     2    DK    20k        20 kohm 2     2    DK    2k        2 kohm 16    16    DK    300        300 ohm 4     4    DK    330        330 ohm 6     6    DK    1.2k        1.2 kohm 4     4    DK    11k        11 kohm 4     4    DK    12k        12 kohm 2     2    DK    22k        22 kohm 4     4    DK    360        360 ohm 4     4    DK    270        270 ohm 6     6    DK    82        82 ohm 2     2    DK    220        220 ohm 2     2    DK    1.1k        1.1 kohm 4     4    DK    30        30 ohm 4     4    DK    1k        1 kohm 8     8    DK    470        470 ohm 4     4    DK    2.2k        2.2 kohm 8    10    DK    0.33W-5 0.33 ohm 5W             3.41 2     2    DK    3386P-202 2 kohm pot             2.00 8    20    MCM    3.3 ohm 1/2 W    3.3 ohm             1.15 4     4    ACK    Y-50 CII 3.9k 1/2 W             .56 4     4    ACK    HB-2-2%RES 10 ohm 2W Carbon         4.80                                 ______ Total                                $11.92
Accessories 1     1    DK    MB252 25A 250V Bridge Rect.         5.40 1     1    DK    3536K Fuse Holder (1)             .77 1     1    DK    3539K Fuse Holder (4)             2.64 1     5    DK    F335 8A Slow Blow Fuse             3.05 4     5    DK    F123 5A Fast Blow Fuse             1.83 8     10    DK    J240 3/4" Threaded Spacers         2.99 8     10    DK    J167 1/4" Tubular Spacers         1.07 4     4    DK    HS111 TO-220 Clip-On Heat Sinks         1.28 1     1    DK    VFP018-R75 1/8" x 3/4" Heatshrink Tubing 1.48 1     1    DK    VFP316-R75 3/16" x 3/4" Heatshrink Tubing 1.75 2     2    DK    Red Binding Post             3.00 2     2    DK    Black Binding Post             3.00 100    100    DK    H342 Mach. Screws 4-40 x 1/4"         1.11 100    100    DK    H346 Mach. Screws 4-40 x 1/2"         1.37 100    100    DK    H216 Hex Nuts 4-40             .93 100    100    DK    H236 Lock Washer #4             1.07 1     1    DK    KE1102 Solder 21 guage 63/37 RA 11b     10.10 2     2    ACK    3505F SC Switchcraft JAX Phono Jack     4.16 2     2    ACK    Shoulder Washer for Phono Jack 2     2    ACK    Flat Washer for Phono Jack 1     1    ACK    Pilot Light, 120V AC             5.69 2     2    ACK    VR8 MAL 2" Capacitor Clamps         3.24 2     2    ACK    E520X6.00 IERC Power Transistor             Heat Sinks                 27.50 1     1    ACK    MCLS5-17-9 B/B Moduline Chassis 19x5x9     53.35 1     1    ACK    SPR5-9 Moduline Chassis Side Panels     19.00 8     10    MCM    21-1150    Power Transistor Insulators     2.69 8     10    MCM    Power Transistor Sockets         9.18 2     2    MCM    #18, 50 ft., Hookup Wire         15.98 1     1    ACE    15A Toggle Switch             3.99 20     20    ACE    Terminal Rings                 1.78 16     16    ACE    Female Disconnects             1.98 100    100    ACE    Small Wire Cable Ties             1.99 3     3    SHACK    Rubber Washers                 2.07 1     1    MARK    003 Power Transformer             32.00 2     2        Circuit Boards                 25.00                                 ______ Total                             $252.44
Do not buy Radio Shack hookup wire. It does not solder properly and the insulation shrinks when the wire is heated by a
soldering iron. I recommend using a quality brand of stranded hookup wire such as Belden, Alpha, Carol, etc., for the chassis
wiring. Digi-Key usually has good prices for wire. I prefer wiring the chassis with 3 colors of wire, e.g. red for +Vcc,
yellow for -Vcc, and black for ground. It is probably cheaper to use a single color. In this case, you should use temporary
masking tape labels on the wires to identify them.
Do not use Radio Shack solder lugs in the chassis wiring. Solder will not bond to the metal that these lugs are made of. I
have seen amplifiers that put out a hum because of bad solder joints to Radio Shack solder lugs. Replacing the lugs with
Walco solder lugs solved the problem. One student recently did not follow my advice and he tried to use Radio Shack solder
lugs to attach R50 and C25 to the loudspeaker output binding posts. After he almost burned up R50 and C25 trying to solder
them to the lugs, he went to Ack Radio and bought Walco lugs which soldered with no problems.
You should not use substitutes for the 1N4148 fast switching diodes. If the diodes which you purchase do not have 1N4148
printed on them, do not use them. I have seen amplifiers not work properly because the vendor supplied a substitute diode
that was not a fast switching diode. The slower diodes cause the protection circuit to be activated on the zero crossings of
the signal and this produces large amounts of distortion.
Last modified at 11:00 AM 8/3/2007
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