Audio Amplifier 386 Revision V1

Description of the Design

Purpose is to have an audio amplifier for use with a Theremin.

This is a pretty simple example of the LM386 more or less right off the datasheet.

LM386 parts are available in several power output options and put out about 3/4 W at 12V.

Front and back ends are both AC coupled so there's no concerns with DC biasing.

Connectors

• RCA jacks for input/output to match "normal" cables easily available.
• J1 = RCA Input
• Center = signal
• Shell = ground 
  
• J2 = RCA, Output 
• Center = signal
• Shell = ground
• J3 - Power connector
• Pin 1 = 12V
• Pin 2 = GND
• RV1 - 0.1" 3 pin pot connection to allow easy wiring to the High Voltage Digital Pot design or an external pot.
• 1 = Signal In
• 2 = Wiper/Signal Out
• 3 = Ground  

Mounting Holes

Two 4-40 mounting holes allow the card to be mounted vertically on two support screws using a simple L bracket.

Version V1

1. Used SIP-x instead of PIN_ARRAY_xX1 parts so the headers have holes that are too small.
2. IN/OUT silkscreens are backwards.
3. J3 close to IC.
4. Placement of parts did not allow a 5mm TB to be used for the power input.
5. C3 part was 11 mm but the parts I bought were 8 mm.