Alesis MultiMix4-USB 4Ch Mixer Repair

[@NewHamInTown]

Hi Ian - I have one of those mixers that I use for ham radio but I've not needed to to use the phantom power. Good to know this is an issue though. Love the style of your videos. Just the right amount of explanation and "on camera" activity. Keep up the good work. Cheers

[@gerrysweeney]

Nice repair there Ian, and nice to see the decade resistor in use :) Gerry

[@IanScottJohnston]

I put a lot of current through it Gerry, way over limits........and it never batted an eyelid!

[@BalticLab]

Lots of my first audio gear was Alesis. They make good stuff! Good vid, too!

[@IanScottJohnston]

UPDATE: I contacted Alesis, they are quite interested in the video and are looking into the issue.

[@blackIce504]

The only thing with the USB model is that it bypasses your sound card, this may not be a big deal if you got a low grade integrated sound chip/codec but if you have a high end one then you loose your quality as it is not going through your sound card, i am sure they used a basic usb sound codec on that, but nice repair and its good to see that Alesis are interested in fixing the problem.

[@IanScottJohnston]

BlackIce504 It only bypasses the sound card if you let it......i.e. I have both the LINE and USB connections to the Alesis active, but can easily select which one I use in the PC's sound card driver. I use the LINE input mostly.

[@blackIce504]

IanScottJohnston Ah the confusion as i seen the usb hooked up you must have been testing. I was also keen to know why you not remove one of the caps and diodes to see if you got 48V from the voltage doubler? or would the voltage be to low?.

[@StarfieldBound]

Great narration, presentation and video.. Nice work!. Enjoyed and learned.

[@bartuchaz]

Hello Ian! Thank you for this video - there is still hope for my Multimix4 USB mixer (120V XLR voltage). Do you still remember this case? What are the connection (soldering) points for the resistor-zeners circuit? I just want to make sure because your multimeter's red probe is blocking the view. Thanks again!

[@TemuulenGanzorig]

How to fix the usb input on a mixer? The sound’s okay when listened through earphones but when recorded on the computer, it sounds horrible. Tried switching usb connector but no luck

[@bsb0011]

Old video I know, but it looks like you have the knobs reversed for channel 3/4 and the main output at 27:17.

[@arcadeuk]

Hi Ian, nice fix there to save you having to deal with an ebay return :) I was however worrying for your decade resistor board as you put a 500wm 1k resistor across 48v... that was nearly 2.5watts going through it! lol :)

[@IanScottJohnston]

Ok for a few secs.........:)

[@jusb1066]

I was thinking to bridge one of the pair of multiplier diodes, but who knows! interesting work around and a good video as always. i am guessing they tested/designed it with lower impedence mics or only tested with two powered at once

[@ianjohnston2843]

With a low impedance mic, and assuming a typical phantom power interface then the load would be about 14mA (48vdc feeding through two parallel 6.8k's to virtual ground). If I'd had time I would have traced the entire circuit......but yes it's a bit wierd it's been designed so sensitively.

[@RobertoHernandezHouse]

Hi there. pretty good video. I have a little problem with the 8 channel version: Channel one has very low output level compared with the others. It has no strange noise and all the pot's work perfectly; the only problem is it doesn't gives the same signal level than the others. By example in Channel 1: gain at 10 and channel volume at 10, and in channel 2 I need gain at 50% and channel volume at 3 and I get the same output level using identical micros. Any idea how can I fix it? Thanx

[@tubical71]

Nice little fix here, Ian:) May try to use a transistor to power up the Zdiode? I really hate these "build to price" designs. A propper P48 uses (what you already told us here) a SquareWave generator followed by a VoltageMultiplier and a regulator to give us a stable P48.... But i´ve also got some nice gear from alesis and it never let me down... Thanx for shring!

[@SeanBZA]

2 24V zener diodes in series across the rail to clamp it would probably do. After the resistor and with 100uF in parallel to keep the noise down. I would disconnect one stage of the multiplier as well.

[@GarysBBQSupplies]

Hi Ian. Is it possible to hook up a condenser mic/s that have a lower resistance so as to put more of a load on the power supply, would that have helped lower the voltage

[@IanScottJohnston]

Mics are built to a spec, and it wouldn't make that much difference even if you could.

[@GarysBBQSupplies]

@@IanScottJohnston That makes sense. I am an electrician and we had to learn DC theory in our 1st 2 years. Great fix!

[@zaprodk]

Why about making an XLR-passtrough plug where you place the Zener+resistor, and dissipate the heat outside of the mixer. No need to worry about internal caps drying out faster.

[@hacker8253]

The have a Alexia multimix fx the makes a piping noise when routing the signal through the fx the weird thing is it wont do it after I cut it off and cut it back on and it will only makes the noise below the fx number 20 it has 99 fx but any thing below 20 and it makes this noise.I can make a video for you.I also had a problem with the 4 channel peak light being constantly lit I fixed that by opening it up and adding solder to a transistor don't know why there was no solder on there at all.

[@ConnieGMK]

What I have found over the years the souldering of the USB on Alesis is pretty poor, so they always breaking.

[@polo5569]

Hi. I have a similar mixer the multimix six and the 1/4 input on line 2 needs to be replaced. I found a place that could sell me the part but they need to know what type of connector it is. So you have any info on the 1/4 inputs? Also did you have to take all the knobs off to take the face of the mixer off?

[@CRONIKMASTERBATR]

I got Dj mixer that I want to fix channel 2 has no output sound when I connect it to my amplifier any video you can recommend I can watch to learn how to fix it thanks

[@BlessTheproducer249]

My Ez-m mini mixer 10x2 is not working up with my microphone what's causing that but it's working perfectly only a mic help me sir what can I do?

[@V1P3RSlab]

Can i suggest audacity software to record and analyze the audio signal? Is an open source and free software ;-)

[@TozeCerdeira]

I need a shematics to fix my Alesis multimix 8 . can you help. Thanks

[@IanScottJohnston]

Sorry I don't have any schematics.

[@ZamMokAlfathani]

Mine mixer suddenly keep on-off, on-off and so on. I don't know what to repair

[@tobortine]

Nice work and interesting video.

[@mahendraswamitapukara7539]

My efx12 Mai yahi problem aa rahi hai kaha par dikhau?plz help me

[@Coolkeys2009]

I wonder if the seller acquired it cheap because it was part of a bad batch?

[@IanScottJohnston]

Yes, could easily have been.......and one reason I wasn't interested in returning it!

[@IanScottJohnston]

I should have mentined, the PSU is the one that came with it....not one of my own albeit "Merry King" branded (one hung lo?)...not Alesis. 10VAC 500mA.

[@jusb1066]

IanScottJohnston yep, very cheap psu, and the design of relying on the exact voltage drop of a cheap psu, well yep, returning it wouldnt have helped, the design is rather poor

[@MariusVideoOfficial]

Hi, I have a multimix 8 usb, the mic channels have an hum noise, the signal works but is unusable with this hum on the first 4 channels. The stereo channel work normally. Do you have some trick or suggestion to solve?