Read the previous entries for this project:
20W Amplifier Project
20W Amplifier Project – Redo
20W Amplifier Project – Prep Work
The remaining components finally arrived, the work can begin on the volume, tone and balance portion of the circuit. A couple things of note before the work is detailed. First is that all the components for this project were purchased via eBay (with the exception of the circuit board), primarily from Tayda Electronics. Good quality and very fast shipping. Second item of note is that ExpressSCH is the tool used to create the schematic.. it’s free and easy to use.
This part of the project was started by breadboarding the LM1036 and associated components. Not difficult, but the challenge is all the ground connections which is more difficult on the PCB than it is on the breadboard.
Here’s a short video of the circuit test:
With the circuit test successful, it’s time to mount it on a PCB. The potentiometers are mounted to the board with all the components for a cleaner installation and shorter Itwire runs (that will hopefully avoid humming sounds).
It’s hard to have a neat wire layout when doing the point-to-point wiring, but it turned out good. Again, ribbon cable wire was used. The circuit tested good and now it’s time to mount into the enclosure. Just need a couple switches for power and input selection, a 3.5mm jack for another input, a chassis mount power connector and some binding posts to complete this project.
Here’s the completed schematic and bill of material for this project:
Capacitors
C1 10 uF 25v
C2 470 uF 16v
C3 2200 uF 25v
C4 100 nF
C5 10 uF 25v
C6 470 uF 16v
C7 2200 uF 25v
C8 100 nF
C9 100 nF
C10 100 uF 25v
C11 47 uF
C12 .47 uF
C13 .01 uF
C14 .22 uF
C15 10 uF
C16 .39 uF
C17 10 uF
C18 .22 uF
C20 .22 uF
C21 10 uF
C22 .22 uF
C23 .39 uF
C24 10 uF
C25 .01 uF
C26 .47 uF
LEDs
D1 LED
ICs
IC1 TDA2003
IC2 TDA2003
IC3 LM1036N
Jacks
J1 3.5mm Stereo
J2 3.5mm Stereo
Resistors and Potentiometers
R1 220 ohm
R2 2.2 Ohm
R3 1 Ohm
R4 220 ohm
R5 2.2 Ohm
R6 1 Ohm
R7 220 Ohm
R8 680 Ohm 1/2W
R9 47k
R10 47k
R11 47k
R12 47k
R13 47k
R14 47k
R15 47k
R16 47k
Switches
SW1 DPDT
SW2 SPST
SW3 SPST