1. 27 - + 10k 1k 100k 0.22uF In Out 50k R3R4 R1 R2 R5* C1 U1 OPA132 2 3 7 4 6 V+ V- CMoy standard [Rainer Boettchers, 2003, rainer@justchords.com] v = R3 + R4 R3 = R4 R3 1 + *) R5 opt., 27.. 47Ohm Cmoy headphone amplifier (© Chu Moy, www.headwize.com) OPA132-pin compatible: LM741 (lower Vcc, lower P0) OPA2132-pin compatible: TL072C, NE5532 (higher Out-Z) R in = R2

2. 27 - + 10k 1k 100k 0.22uF In Out 50k R3R4 R1 R2 R5 C1 U1 OPA132 2 3 7 4 1 V+ V- CMoy 47 design [Rainer Boettchers, 2003, rainer@justchords.com] U2 OPA132 3 2 7 4 1 V+ V- - + 27 Cmoy47 headphone amplifier (© Chu Moy/Apheared, www.headwize.com)

3. 47 - + 1M In Out R2 R5 U1 OPA132 2 3 7 4 6 V+ V- Simple impedance follower pin-compatible opamp:TL072C (lower quiescent current) Impedance follower [Rainer Boettchers, 2003, rainer@justchords.com]

4. 27 - + 10k 1k 100k 0.22uF LineInR Out 100k R3R4 R1 R2 R5* C1 U1/1 OPA132 2 3 7 4 1 V+ V- 100k 27 - + 10k 1k 100k 0.22uF LineInL Out 100k R3R4 R1 R2 R5* C1 U1/2 OPA132 6 5 7 4 7 V+ V- 100k - + - + 2.2k 1k 4.7k 1k TL072C U2/1 7 4 V+ V- 10k 7 4 V+ V- U2/2 0.22uF InstrIn 1M 2 3 1 6 5 7 Practice amp w/ LineIn & Instr (var. Line-In) R6 R7 0.47uF R8 1M

5. 27 - + 10k 1k 100k 0.22uF LineInR Out R3R4 R2 R5* C1 U1/1 OPA132 2 3 7 4 1 V+ V- 47k 27 - + 10k 1k 100k 0.22uF LineInL Out R3R4 R2 R5* C1 U1/2 OPA132 6 5 7 4 7 V+ V- 47k - + - + 100k 2.2k 1k 4.7k 1k TL072C U2/1 7 4 V+ V- 10k 7 4 V+ V- U2/2 0.22uF InstrIn 1M 2 3 1 6 5 7 Practice amp w/ LineIn & Instr (const. Line-In) R6 R7 0.47uF R8 1M

6. Battery common rail supply 470uF 4.7k + 470uF + 4.7k 3.3k +9V -9V 2 x 9V LED

7. 27 - + 620k470k 10k 0.47u In Out R3R4 R2 R5* C1 U1 OPA132 2 3 7 4 6 V+ V- g = R4 R3 *) R5 opt., 27.. 47Ohm 10k Single supply operation [Rainer Boettchers, 2003, rainer@justchords.com] Single supply operation for buffer amp R in = R3 100u + 220p 0.22u +

8. Musical EQ

9. 1234567891011121314151617181920212223242526272829 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 OpAmp audio projects Date:14 April 2015 18:26 Page:9 0 0 Out A Out B In A In B Vcc+ Vcc - Gnd 27 10k 0.22u 4.7u 100k 1k OPA2132 [Rainer Boettchers, 2003, rainer@justchords.com] 4.7u 7812 7912 4700u + + + - + - B80C1500 ~ ~ ~ ~ 15V~ CMoy standard, power supply version

10. 1234567891011121314151617181920212223242526272829 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 OpAmp audio projects Date:14 April 2015 18:26 Page:10 0 0 Out A Out B In A In B Vcc+ Vcc - Gnd 47 1M OPA2132 [Rainer Boettchers, 2003, rainer@justchords.com] 47u ++ Pickup follower 10k

11. 1234567891011121314151617181920212223242526272829 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 OpAmp audio projects Date:14 April 2015 18:26 Page:11 0 0 Out A Out B In A In B Vcc+ Vcc - Gnd 27 10k 0.22u 4.7u 100k 1k OPA2132 [Rainer Boettchers, 2003, rainer@justchords.com] 4.7u 7812 7912 4700u + + + - + - B80C1500 ~ ~ ~ ~ 15V~ OPA2132 27 CMoy 47, power supply version

12. 1234567891011121314151617181920212223242526272829 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 OpAmp audio projects Date:14 April 2015 18:26 Page:12 0 0 Out A Out B In A In B Vcc+ Vcc - Gnd 27 10k 0.22u 220k 1k OPA2132 [Rainer Boettchers, 2003, rainer@justchords.com] 470u + + OPA2132 27 4.7k V+V- CMoy 47, battery version

13. 1234567891011121314151617181920212223242526272829 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 OpAmp audio projects Date:14 April 2015 18:26 Page:13 0 0 [Rainer Boettchers, 2003, rainer@justchords.com] CMoy standard, battery version Components side viewPrint side view

14. 1234567891011121314151617181920212223242526272829 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 OpAmp audio projects Date:14 April 2015 18:26 Page:14 0 0 [Rainer Boettchers, 2003, rainer@justchords.com] CMoy standard, battery version (alternate layout)

15. 1234567891011121314151617181920212223242526272829 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 OpAmp audio projects Date:14 April 2015 18:26 Page:15 0 0 [Rainer Boettchers, 2003, rainer@justchords.com] CMoy booster, low power battery version R3gain 4.7k5.7 2.7k3.7 1.0k2.0 Components side viewPrint side view

16. 1234567891011121314151617181920212223242526272829 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 OpAmp audio projects Date:14 April 2015 18:26 Page:16 0 0 In N Vcc+ TL072 [Rainer Boettchers, 2003, rainer@justchords.com] Single supply pickup booster 10k + 10u 27 680k 470k 10k 0.47u 10k + 27 680k 0.47u 470k In B 10k Gnd 10u In N Vcc+ TL072 10k + 10u 27 680k 470k 10k 0.47u 10k + 27 680k 0.47u 470k In B 10k Gnd 10u Components side viewPrint side view

17. 1234567891011121314151617181920212223242526272829 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 OpAmp audio projects Date:14 April 2015 18:26 Page:17 0 0 [Rainer Boettchers, 2003, rainer@justchords.com] CMoy practice amp, battery version, const. LineIn Out A Out B In A In B Vcc+Vcc - Gnd 27 10k 0.22u 4.7k 47k 100k1k OPA2132 4.7k 470u/25V + + Main stage Preamp stage Instr 0.22u 1M TL072C Gnd 1k 4.7k 1k 2.2k Pre out Vcc+ Vcc - Instr. vol. Gnd Put feedback resistors on solder pins to adapt gain to instrument output level Comments: May be 10... 100k pots; if > 100k put 10k across 100k Pre In 47k 100k 0.47u 1M

18. 1234567891011121314151617181920212223242526272829 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 OpAmp audio projects Date:14 April 2015 18:26 Page:18 0 0 Out A Out B In A In B Vcc+ Vcc - Gnd 27 10k 0.22u 4.7k 100k 1k OPA2132 4.7k 470u + + [Rainer Boettchers, 2003, rainer@justchords.com] CMoy standard, battery version, single board Input Headphone Volume

19. 1234567891011121314151617181920212223242526272829 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 OpAmp audio projects Date:14 April 2015 18:26 Page:19 0 0 Out A Out BIn A In B Vcc+ Vcc - Gnd 27 10k 0.22u 4.7k 100k OPA2132 [Rainer Boettchers, 2003, rainer@justchords.com] 4.7k 470u + + CMoy standard, switchable gain, battery version 4701k2.2k4.7k4701k2.2k4.7k 1: g = 22 2: g = 11 3: g = 6 4: g = 3 and more 1414

20. 1234567891011121314151617181920212223242526272829 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 OpAmp audio projects Date:14 April 2015 18:26 Page:20 0 0 [Rainer Boettchers, 2003, rainer@justchords.com] Equalizer EQ3 In Vcc- 1u Gnd Components side view TL072 Vcc+ Out 220k 1u 1.8k 3.6k 11k 500k 1.8k 5n 3.6k 5n 22n 50n 11k 100k