Microphone Mixer

Author	Views	Views Today	Rank	Comments
Anatoly I. Shikhatov	254,320	2		26

This relatively simple mixer was designed for three dynamic microphones, but can be re-designed for more or less. Level and tone controls are available to tailor the sound to your needs.

Schematic

Parts

Part	Total Qty.	Description	Substitutions
R1, R2, R3	3	1K 1/4W Resistor
R4, R5, R6	3	10K Logarithmic Pot
R7	1	1Meg 1/4W Resistor
R8, R10	2	10K 1/4W Resistor
R9, R11	2	100K Linear Pot
C1, C2, C5, C6	4	0.1uF Ceramic Disc Capacitor
C3, C4	2	22nF Ceramic Disc Capacitor
U1, U2	2	741 Op Amp
J1, J2, J3	3	Input Jacks Of Your Choice
MISC	1	Board, Wire, Knobs, IC Sockets

Notes

Email Anatoly I. Shikhatov with questions, comments, etc.

R1-R3 are level controls. R9 and R11 control bass and treble, respectively.

Since the circuit draws such low current, two 9V batteries can be used for a power supply.

Building the mixer in a metal case will cut down on noise.

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Comments

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Jon Microphone Mixer Friday, March 11, 2016 8:55:10 AM

Hi Experts. For a personal monitor/mix. Could this be used to feed a headphone amp with the inputs J1-3 passing through (as before) to the main mixer ?? OR where would this fail ? Thanks, Jon

anonymous Microphone Mixer Thursday, December 27, 2012 9:46:37 AM

Anyone know the noise floor could below 2uV(-115dBV) A-weighting?

Emmantrop Microphone Mixer Tuesday, September 04, 2012 6:32:54 PM

Thanks, I build this circuit and it work fine.

anonymous Microphone Mixer Saturday, May 28, 2011 1:10:04 PM

1.For questioner on Friday, February 12, 2010, look at schematic, that clearly shows + and minus 9v. 2.For shoaib, follow the instruction, IE use 2 9v batt, eliminating MAX error, Feed in 1Khz signal (or music) at uV to 1 volt and lisen or look with oscope at U1 pin6, R8 and then u2 pin 6 to check for signal stopage. Generate signal with pot or volt divider from strong source. 3.Bill, look harder, it is also 0.022 uF or microfarad. Do not substitute much, IE 20 uF or 24uF as it will likeley not work well. 4.For Sunday, January 06, 2008 question, you can not use 386 but you can use TL071 which will work down to less than 8 volts. Put 2 10k resistors (in series) accross batt and make the center of them the ground of the circuit (making 2 4.5v "supplies). It will not have much head room. 5. balu, as above, you can use TL071 and use the Batt supply to test if the hum is from your power supply. Enclose it is metal case, make all wiring close, use a shielded cable to the mic. Increase size of C1,2,5,6, add a 5 or 10uF to each batt to ground(watch polarity, + to +).

Feil Microphone Mixer Monday, April 19, 2010 10:08:37 PM

this circuit is nice, but do TL0712 works like the 741 OP AMP? what are the characteristics of TL072?

anonymous Microphone Mixer Friday, February 12, 2010 1:41:24 PM

When you say 2 9v batteries, do you mean in series or in parallel? Does that mean the circuit needs 18'v?

bikash Microphone Mixer Tuesday, August 25, 2009 4:30:40 AM

ok this is nice and these are helpng me to know aboutr electroncs so a heartiest thanks to u.

shoaib Microphone Mixer Monday, January 26, 2009 2:33:17 AM

i complete circuit & cheak out many time but my circuit not work i use the max1044 ic for 9v+ 9v- supply what i do help any one plz

anonymous Microphone Mixer Sunday, May 25, 2008 9:52:34 AM

usE TL072 op instead of 741

Bill Microphone Mixer Friday, April 11, 2008 10:26:33 PM

I can't find the two 22nf capacitors. can I substitute them with another value?

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Jon	Microphone Mixer	Friday, March 11, 2016 8:55:10 AM
Hi Experts. For a personal monitor/mix. Could this be used to feed a headphone amp with the inputs J1-3 passing through (as before) to the main mixer ?? OR where would this fail ? Thanks, Jon
anonymous	Microphone Mixer	Thursday, December 27, 2012 9:46:37 AM
Anyone know the noise floor could below 2uV(-115dBV) A-weighting?
Emmantrop	Microphone Mixer	Tuesday, September 04, 2012 6:32:54 PM
Thanks, I build this circuit and it work fine.
anonymous	Microphone Mixer	Saturday, May 28, 2011 1:10:04 PM
1.For questioner on Friday, February 12, 2010, look at schematic, that clearly shows + and minus 9v. 2.For shoaib, follow the instruction, IE use 2 9v batt, eliminating MAX error, Feed in 1Khz signal (or music) at uV to 1 volt and lisen or look with oscope at U1 pin6, R8 and then u2 pin 6 to check for signal stopage. Generate signal with pot or volt divider from strong source. 3.Bill, look harder, it is also 0.022 uF or microfarad. Do not substitute much, IE 20 uF or 24uF as it will likeley not work well. 4.For Sunday, January 06, 2008 question, you can not use 386 but you can use TL071 which will work down to less than 8 volts. Put 2 10k resistors (in series) accross batt and make the center of them the ground of the circuit (making 2 4.5v "supplies). It will not have much head room. 5. balu, as above, you can use TL071 and use the Batt supply to test if the hum is from your power supply. Enclose it is metal case, make all wiring close, use a shielded cable to the mic. Increase size of C1,2,5,6, add a 5 or 10uF to each batt to ground(watch polarity, + to +).
Feil	Microphone Mixer	Monday, April 19, 2010 10:08:37 PM
this circuit is nice, but do TL0712 works like the 741 OP AMP? what are the characteristics of TL072?
anonymous	Microphone Mixer	Friday, February 12, 2010 1:41:24 PM
When you say 2 9v batteries, do you mean in series or in parallel? Does that mean the circuit needs 18'v?
bikash	Microphone Mixer	Tuesday, August 25, 2009 4:30:40 AM
ok this is nice and these are helpng me to know aboutr electroncs so a heartiest thanks to u.
shoaib	Microphone Mixer	Monday, January 26, 2009 2:33:17 AM
i complete circuit & cheak out many time but my circuit not work i use the max1044 ic for 9v+ 9v- supply what i do help any one plz
anonymous	Microphone Mixer	Sunday, May 25, 2008 9:52:34 AM
usE TL072 op instead of 741
Bill	Microphone Mixer	Friday, April 11, 2008 10:26:33 PM
I can't find the two 22nf capacitors. can I substitute them with another value?