Author Topic: An audio mixer kit with no schematic  (Read 1070 times)

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Offline K-ExperimentTopic starter

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An audio mixer kit with no schematic
« on: May 24, 2019, 03:59:40 pm »
I got an Audio mixer kit but there is no available schematic diagram so I need help in making my own audio mixer with the following parts:

2,   100 ohm resistor 1/4w
10, 1k   ohm resistor 1/4w
2,   10K ohm resistor 1/4w
1,   1M  ohm resistor 1/4w
4,   IN4001 Diodes
1,   Red 5mm LED
4,   0.1      uf (104) ceramic capacitors
2,   0.0002 uf (22)  ceramic capacitors
2,   1000   uf  16v   electrolytic capacitors
2,   100K  ohm Potentiometer
6,   10K    ohm Potentiometer
1,   250v 0.2a fuse
1,   250v spst switch
1,   220v to 9v 200a transformer (secondary is center tapped)
2,   UA741cp op-Amp

(Mains Voltage is 220v 60Hz)(ps: there was no circuit board)

 

Offline Zero999

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Re: An audio mixer kit with no schematic
« Reply #1 on: May 24, 2019, 04:19:02 pm »
I can guess, but the old 741 isn't a very good op-amp for audio. It will work, but isn't ideal.
 

Offline soldar

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Re: An audio mixer kit with no schematic
« Reply #2 on: May 25, 2019, 01:36:52 pm »
I got an Audio mixer kit but there is no available schematic diagram so I need help in making my own audio mixer with the following parts:


No PCB? No schematic? You bought this as an "audio mixer"? Because what you got is not an audio mixer at all. You just got a bunch of parts.

If you want an audio mixer you might as well start all over again. It will save you time and trouble.
All my posts are made with 100% recycled electrons and bare traces of grey matter.
 

Offline magic

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Re: An audio mixer kit with no schematic
« Reply #3 on: May 25, 2019, 03:04:27 pm »
Something like figure 4 here must have been intended.

I'm only puzzled by the choice of resistors, 1k seems low for the inputs and no other value is available in enough quantity.
 

Offline Arjunan M R

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Re: An audio mixer kit with no schematic
« Reply #4 on: May 25, 2019, 03:16:32 pm »
I can guess, but the old 741 isn't a very good op-amp for audio. It will work, but isn't ideal.
NE5534 will be a good solution.
Its a low noise opamp built for audio purposes.
Here is the datasheet http://www.ti.com/lit/ds/symlink/ne5534.pdf
« Last Edit: May 25, 2019, 03:18:32 pm by Arjunan M R »
 

Offline Zero999

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Re: An audio mixer kit with no schematic
« Reply #5 on: May 25, 2019, 10:22:11 pm »
I can guess, but the old 741 isn't a very good op-amp for audio. It will work, but isn't ideal.
NE5534 will be a good solution.
Its a low noise opamp built for audio purposes.
Here is the datasheet http://www.ti.com/lit/ds/symlink/ne5534.pdf
That's a sensible enough suggestion. Don't forget the important 22pF frequency compensation capacitor in applications with a noise gain of under three.
 


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