Audio Booster, with one transistor

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

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 BC168CBC183LB and BC183LC BC238C BC548A and BC548C PBC109 KT373AERROR 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 ofthe 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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