LM1875 2x 20W amplifier PCB (printed circuit board), stereo, include PSU and tone control (bass, treble). Price per each.

Parts List, amplifier section (per stereo):

• R1: 1M 0.5W (not in PCB)
• R2, R4: 22k 0.5W, 4 pcs
• R3: 1k 0.5W, 2 pcs
• R5: 1R 0.5W, 2 pcs
• C1: 1uF-2.2uF MKP, 2 pcs
• C2: 22uF 16V or higher, 2 pcs
• C3, C4: 0.1uF +50V, 4 pcs
• C5: 0.22uF (220nF) +50V, 2 pcs 
• C6, C7: 100uF +35V, 4 pcs
• IC: LM1875, 2 pcs
• Other: mica isolator (2x), heatsink (1x), screw/bolt-nut (2), thermal pasta, PCB spacer/stands-off (2x) 

Parts List, PSU:

• Diode: 3A - 6A, 4 pcs
• C: 2200uF 35V or higher, 2 pcs
• Power transformer: 18V-CT-18V, 2A/stereo minimum (= 5A)