Solid State Preamp Reviews

Potentiometers:
VR1: Your choice of ALPS "Black Beauty" 100k stereo audio taper pot, Penny & Giles RF15-2-20k-A 20k stereo audio taper pot or ALPS "Budget Gourmet" 100k stereo audio taper pot (Radio Shack part #271-1732).

VR2 & 3: Bourns 3386-OT1 5k sealed cermet miniature trimpot.

Buffers:
IC1 & 2: PMI BUF-03AJ milspec version. (The impecunious can experiment with the less-expensive BUF-03J and -EJ commercial versions, which have reduced slew rates and drive capabilities, but these have not been auditioned.)

Switches:
SW1 & 2: Electroswitch 900A two-pole six-position rotary switch (see text).

Resistors:
R1 & 3: 1k

R2 & 4: 12.9k

R5 & 6: 10 ohms

R7 & 8: 1.5k

All resistors 1/2W metal-film such as Holco, Resista, Vishay, etc.

Capacitors:
C1, 3, 8, & 10: 4,700µF/35V Panasonic TSW

C2 & 9: 100µF/25V Panasonic HF

C4-7 & 11-14: 0.01µF/100V film-type

C15-18: 470µF/35V Panasonic HF

C19-22: 1µF/50V Panasonic V

Diodes:
D1-4 & 11-14: 50 SQ100 Schottky Barrier Diodes, or simply use one 6A, 100V bridge rectifier each for D1-4 and 11-14.

D5-10: 1N4002

Regulators:
U1: Linear Technology LT1085CT

U2: Linear Technology LT1033CT

Power Transformer:
T1: Avel-Lindberg Type D3031 160VA 118V/22V+22V CT.

Suppliers:
Penny & Giles: 2716 Ocean Park Blvd. #1005, Santa Monica, CA 90405. Tel: (213) 393-0014. Fax: (213) 450-9860.

Newark (PMI BUF-03AJ, Bourns trimpots): call for your local branch distributor at (512) 338-4845.

Electroswitch: P.O. Box 41129, Raleigh, NC 27604. Tel: (919) 833-0707. Fax: (919) 833-8016.

Michael Percy (metal-film resistors, film caps, Wonder Solder, audiophile hookup wire): P.O. Box 526, Inverness, CA 94937. Tel: (415) 669-7181.

DigiKey (Panasonic capacitors, rectifiers, heatsinks): call (800) 344-4539 to order parts.

Old Colony Sound Lab (complete power supply kit including printed circuit board; ask for kit KG-5): P.O. Box 243, Peterborough, NH 03458-0243. Tel: (603) 924-6371/924-6526. Fax: (603) 924-9467.

Linear Technology Corporation: 1630 McCarthy Blvd., Milpitas, CA 95035. Tel: (408) 432-1900. Fax: (408) 434-0507.

Avel-Lindberg: 5 Old Town Rd., Unit 47, New Milford, CT 06776. Tel: (203) 355-4711. Fax: (203) 354-8597.