Audio Booster Schematic

Parts List:
Part Description Radio Shack # DigiKey # Notes
Q1  2N3392  NA  2N3392-ND  Transistor, NPN
R1  47K resistor  271-1342    yellow purple orange gold
R2  470K resistor  271-1354    yellow purple yellow gold
R3  10K resistor  271-1335    brown black orange gold
R4  560 Ohm resistor     560QBK-ND  green blue brown gold
R5  100K potmeter + switch      Linear, not audio
R6  270 ohm resistor  271-1314    red purple brown gold
LED1  LED, red  276-033    any
C1  Capacitor, .05-.1uF      Ceramic, 50V type
C2  Capacitor, 0.1uF  272-1069    Ceramic, 50V type
C3  Capacitor, 33uF/25V      Electrolytic
J1/J2  RCA Jacks      Input/output

Printed Circuit Board     Part placement diagram

The 2N3392 transistor is a (cheap) low-power, low-noise, high-gain type in a TO-92 case and can be replaced by a NTE199 or ECG199. If you wish to use a TUN, cross reference the parameters with one of the units from this list: TUP-TUN
Potentiometer R5 of 100K is a linear type with an on/off switch attached.
The value of C1 may need to be between 0.05uF and 0.1uF (47nF/100nF). Experiment with the value for best performance.
Capacitor C3's working voltage should be at least 16V.

Some replacements for the 2N3392 are (not verified): 
       2N3392 (e-c-b)
       NTE199 (closest match) (e-c-b)
       BC168B and BC168C 
       BC183LB and BC183LC
       BC548A and BC548C

ERROR FIXED! The 2N3392 was shown with the 'b' and 'c' reversed.  The above and the 2N3392 as shown in the 
layout diagram are correct. The base and collector legs have to be twisted (reversed) for the printed circuit board or the circuit will 
absolutely not work.  Apologies for the error!
Note that the pinout for the 2N3392 is different from the substitutes. For the NTE199, a direct match, you have to twist the legs of the collector and base so they switch places (e-c-b instead of e-b-c) and that way fits into its place on the pcb. On a future date I will modify the pcb for both types of transistors.

A KIT for this circuit is available. Audio Booster

The phone number for DigiKey is 1-800-Digi-Key.

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Copyright ©1996 - Tony van Roon