How to mix or blend stereo channels into a monoaural amp

Ron Czapala

I bought some TDA5072A TDA7052A amplifier ICs and am pleased with the sound and the fact that so few external components are needed.

What is the best way to combine stereo channels like the VEHO 360 and similar devices do?

Is there a simple circuit or IC to accomplish this?

Thanks,
Ron

davejames

Hi Ron,

Put a 10k 1/4W carbon film resistor in each channel, and then tie their open ends together for a "down & dirty" passive mixer. Route that combined signal to your amp.

Heck - even 1k should be sufficient.

Phil Pilgrim (PhiPi)

A couple of 1K resistors from the two channels to a common point ahead of the amp input should do the trick. BTW, I assume you meant the part number to be TDA7052, right?

-Phil

Ron Czapala

davejames wrote: »

Hi Ron,

Put a 10k 1/4W carbon film resistor in each channel, and then tie their open ends together for a "down & dirty" passive mixer. Route that combined signal to your amp.

Heck - even 1k should be sufficient.

Thanks! Didn't realize it could be that simple.

Ron Czapala

Phil Pilgrim (PhiPi) wrote: »

A couple of 1K resistors from the two channels to a common point ahead of the amp input should do the trick. BTW, I assume you meant the part number to be TDA7052, right?

-Phil

Thanks Phil! Yes I meant TDA7052A.

davejames

Ron Czapala wrote: »

Thanks! Didn't realize it could be that simple.

It can be as complicated as you want!

*8)

LoopyByteloose

Buy a small mixer kit from Elliot Sound Products. These are very reasonable and well designed printed circuit boards. You can use passive mixing, but it may not be as good as an op amp.

Elliot Sound Products explains both, the best layouts, and the pros and cons. There are two ways to configure a mixer input for an op amp and one way is definitely wrong.

http://sound.westhost.com/
http://sound.westhost.com/articles/audio-mixing.htm

Take a good look at Virtual Earth Mixers to eliminate cross talk.