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

8019 E. Slauson Avenue Montebello, CA 90640 (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