Picture of Audio Mixer Upgrade
In this instructable i'll show you how i will upgrade my Behringer Eurorack MX802A. The Behringer Eurorack MX802 is a nice 8 channel mixer i picked up a few years ago on Ebay for about $50. It was purchased for use as a portable Podcast Audio mixer and is now serving as my Microphone input for Skype calls. As my Podcasting audio mixer it was carried around in a case allowing me to record a podcast from anywhere with up to 4 people. The problem was i had to use my old Creative Soundblaster MP3+ USB Soundcard to connect the mixer to the laptop and even my home PC. That sound card is still being used as the primary sound card for my PC since the on board sound died. Now days portable audio mixers come with USB audio built in. So to help reduce the clutter around my PC and update the mixer to fit the specs of it newer cousins i figured it was time to Integrate the Soundblaster into my Mixer.

Materials Needed:

- Behringer Eurorack MX802A (any Audio Mixer will do)
- Creative Soundblaster MP3+ USB Soundcard (any USB Audio device with stereo inputs and outputs will do)
- Speaker Wire
- 1/8" Phone Jack
- Set of standoffs with screws

Tools Needed:

- Soldering Iron
- Phillips Head Screwdriver
- 3/32", 1/4 ", 9/64", 7/32" and 3/8" Drill bits
- Jewelers files
- Scribe
- Tin Snips
- Needle Nose Pliers
- Razor Blade
- Wire Cutters/Strippers
- Painters Tape

Updated 1/27/2012 with wiring fixes and a new feature. See Step 8 for the update. 
padbravo1 year ago

this is a very nice instructable.
tks for posting it.... I have a mixer more or less like this, but mine is a RadioShack, 2 tape in, 2 turntable and 3 mics in.

so, maybe it could improve with this kind of upgrade.

lshoesmith2 years ago
Hey - Great instructable!
I was wondering however if you could tell me what type of power adapter this mixer uses, I bought one with the same power input but can't find a psu to plug in to it.
Cheers! :)
mpilchfamily (author)  lshoesmith2 years ago
What brand and model of mixer did you get? Have you done a search for a replacement power block?
Its a Alesis Multimix 8 - I just can't seem to find the type of psu here.
Its an 18V mixer :)
mpilchfamily (author)  lshoesmith2 years ago
Here is what your looking for. Most of these mixes use the same type of power supply with the same connector.

iceng2 years ago
You do good detail work.
mpilchfamily (author)  iceng2 years ago
DustySeven73 years ago
If you want to bring the led of the sound card to top a easy way to do so would be a light pipe. Glue it to the led on the card, drill a hole in the top of the case for it, glue the other end of the light pipe.
That technique is used in a lot of products. mainly routers. smd is smaller and uses less power.
Hope that is a idea that can help you out
jakdedert3 years ago
The light pipe for adding the indicator is a good idea. If the circuit board is single-sided, you might be able to simply drill a hole through it to get the fiber-optic through to where you need it. Simply pick out an 'unpopulated' part of the board and drill a hole, using a long enough bit to continue through the panel above. Of course, you may not be able to determine what's on the other side of the board. Perhaps a small notch could be filed along one edge of the pcb to pass the optic cable to the other side.

If I were doing this project, I'd consider enclosing (shielding) the Soundblaster to avoid any digital noise getting into the audio circuits; and would definitely use shielded cable for the interconnects. Also, while you're in there, a few dB of noise reduction might be realized by moving that power circuit outboard of the mixer, putting it into a small box like they do on more expensive units.
The power supply for these mixers (or, this particular mixer) is a brick. It connects to the back of the mixer with a DIN plug.
Oh duh...I've got the same mixer; although it was given to me and I've never used it beyond the initial checkout and minor repair. It came from the factory with several switches needing to be 'exercised'...had a bad hum and distortion until I did that, which is how I got it for free.
mpilchfamily (author)  jakdedert3 years ago
From what i've read these mixers are hit or miss brand new. But if its a good one then its a reliable one. Mine seems to do pretty good.
clairey3 years ago
This is great! Picked up one of these for a fiver a couple of months back... I'd say this mod is definitely worth that much... :)
Earthscum3 years ago
Very cool idea! I'm staring at the same mixer and thinking that I may need to bug my guitarist for my Edirol back, lol.
For the status LED, you could run a short piece of fiber optic cable from the LED to a convenient point in the mixer housing. It would transfer the light of the LED without the need to desolder and resolder the board.

Thanks for this guide. I have an old mixer I can certainly upgrade this way!
mpilchfamily (author)  kevintumlinson3 years ago
Good idea. But the problem still remains getting at any point at the top of the mixer without having to remove the main board. I think i'll open it up again tonight and see what i can do to get the status light moved. I should have an optical cable somewhere.

I'll post an update if i can pull it off and if i have an optical cable.