Off-Grid Party Sound Systems

Step 5 Mixers

If you want to have a microphone or any 2nd input in addition to your mp3 player then you need a powered mixer.   Also, the higher-power 100W amplifiers need a powered mixer just to boost the signal level from the mp3 player.  Without the signal boost you just can't get maximum volume out of the amp.

There are a couple of different suitable mixers available around $50.  I've been using the Rolls MX51s, which calls itself a "stereo powered mini line mixer".  you can get it from parts-express.com, amazon, and others.  there are some other brands with nearly identical products.

How to use the mixer:  

• the mixer sits between your inputs (mp3 player, mic) and your output (amplifier).  plug your mp3 player and mic into the 'input' jacks on the mixer.  
• plug the 'output' jack on the mixer to the input of your amplifier.  
• The mixer also needs DC power, most models like the Rolls have a wall-wart but run on DC power internally - 9V and 12V are common.
• The Rolls runs on 12V internally, which is very convenient for our battery-powered setup.  I just cut the wall wart off the power cord that came with it and wired it straight to my 12V battery.
• You must connect the ground wires between the amp and the mixer, or you will get hum or even damage the amp.  With a 12V system this is easy, the amp and mixer should run from the same 12V battery.
• If you are building a 24V system: check the wiring diagram below.

Comments

[chriscab]

With this setup of 24V, TK2050, and a mixer/preamp, what should be the current rating of the switch and fuse?

[damiengwalker]

Do you know if a phonograph preamp will work?
How much do you need to boost the signal by to make this work?

Thanks for the help.

FYI: I have the TK2050 and measured a power draw of 37 Watts (total) using an ipod and 2 8 Ohm speakers.

[cjones-2]

(removed by author or community request)

[cjones-2]

ahhh there !


and could I use this Valve Class A Tube Headphone Amplifier pre Bravo V2 AU1 as the level booster ?

[dan]

most headphone amps probably would work for this, yes.