Portable mixer with four stereo headphone output.

Monstruarte · Joined: Sep 25, 2009 Posts: 73 Location: Argentina

Hi everyone! Greetings to all from Argentina! Surprised

(google translator <<ON>>)

Idea

Lately I'm much time outside in the park.
The idea is a master interface that allows connecting our electronic musical instruments x 4 (all portable, iphones, ipads, Gameboys, diy synth, etc), and listen through four stereo outputs (headphones) with individual volume control for each one. (stereo x4)

In brief:

4X STEREO IN
4X VOLUME CONTROL
4X STERO OUT

1X MAIN STEREO LINE OUT (monitor/all signals)

I have compiled these links:

THE MIXER

Posted Image, might have been reduced in size. Click Image to view fullscreen.

and

THE POWER
http://www.beavisaudio.com/projects/NoisyCricket/

Posted Image, might have been reduced in size. Click Image to view fullscreen.

http://www.beavisaudio.com/projects/NoisyCricket/

Idea

I think the Power Amplifier: LM386N1 is the best. (everyone uses).
The Beavis audio "Noisy Cricket" work with 9v, but I do not understand if it is enough power to feed the four headphones.

my main problem is the use of voltage. I not understand how to make the headphones sound loud, clear and no break.

Question

any suggestions?

Very Happy

Monstruarte · Joined: Sep 25, 2009 Posts: 73 Location: Argentina

anybody?

Keysandslots · Posted: Tue Sep 18, 2012 5:00 pm Post subject:

Looks like you already know more than I know but headphones are not very easy to drive because their impedances may all be different. A slightly off-topic option for you may be to use ILP modules to build a mixer and headphone amp. I have a bunch, do some research and let me know if it might be something you could use.

They are on eBay now but the auction is ending soon. If you are interested, ignore the auction and send me a pm.

Randy

PHOBoS · Posted: Tue Sep 18, 2012 5:27 pm Post subject:

I wouldn't use a passive mixer (might work, would have to try). Instead use an active mixer like this
Posted Image, might have been reduced in size. Click Image to view fullscreen.

(that one has the - of the battery connected to a stereo ouput jack so if you plug in a monojack it turns on,
but you can just attach the - of the battery to ground)

keep in mind that if everything you use is stereo, you would have to make 2 mixers and use either 8 monopots
(so you can adjust levels for left and right seperately), or use 4 dualpots.

you will also need an amplifier for each headphone if you want individual volume control.

For stereo signals that would mean 8! of those LM386 amps.

btw the amplifier circuit you posted has some extra features which you probably don't need,
but could be nice (again; would have to try).