JUST MIXER Audio Mixer – Battery/USB Powered Portable Pocket Audio Mixer w/ 3 Stereo Channels (3.5mm) Plus On/Off Switch

(10 customer reviews)



Just Mixer


Designed by professional sound equipment makers to fulfill a need that has yet to be met, the JUST MIXER by Maker Hart is a simple mixer without too many bells and whistles. However, it is perfect for those who need a reliable and accessible option to combine audio from up to 3 devices (smartphones, tablets, computers, MP3 players, Amazon Echo/Dot, game consoles, microphones, instruments, etc.) and output to a single set of headphones or speaker. With 3.5mm input jacks, you can easily connect your devices with AUX cables, and then adjust each input separately. Powered by either batteries or micro USB cable, this portable mini mixer can be used just about anywhere, including while on the go and in the car.

Besides personal workstation use, the Just Mixer can also be used by musicians, DJs or audio technicians to monitor audio output, The Just Mixer can save you from lugging around heavy equipment and can be used in most settings, be it a home recording studio, street venue, music club, or anywhere you’d like to perform or record. It is also ideal for combining different sound inputs in webcasting on Facebook Live, Youtube, and other live streaming platforms.

***Please visit Maker Hart website -> Product -> Just Mixer to watch videos on how to use Just Mixer with keyboard, smartphone, microphone and Amazon Echo Dot.

Mixer connections

  • 3 x 3.5mm STEREO INPUT: 2 input jacks that can be split into 4 x 1/4″ mono (mono to stereo adapter required), 1 AUX In
  • 1 x 3.5mm STEREO OUTPUT: Output to headphones or speakers

all just mixer


  • Low batteries are a common source of noise. If noise is heard, please remove the batteries and try a USB charger or power supply or using fresh, high quality alkaline batteries that can produce 1.5V (rechargeable batteries that produce less than 1.5V will likely cause noise).
  • If you wish to power the Just Mixer using a USB power bank, we recommend the EnergyFlux HEF power bank. Other power banks may not work because the Just Mixer takes very little power and most USB power banks will shut off automatically when too little power is drawn.
  • First increase the volume setting on your input device, then gradually increase channel volume. Use the mixer’s gain knob sparingly. Only increasing volume settings on the mixer may cause a high noise level.
  • For extended use, we recommend using USB power. Batteries last 8 to 12 hours, and possibly less with higher gain applications such as acoustic electric guitars.
  • Additional static noises may arise due to interference from other connections in close proximity. Do not power mixer from a charging hub that also powers other devices, especially if those devices are also plugged into the mixer. This may cause a ground loop (low hum).

Features and specs

  • OVERLOAD INDICATOR: Lights up when mixed signal level is too high
  • BALANCE: Adjust L/R balance for each channel GAIN: Adjust and amplify signal strength for each channel
  • MASTER and CHANNEL VOLUME SLIDERS: Adjust volume of overall and individual channels
  • USB POWER JACK: Micro USB socket (cable not included)
  • Gain: Max. 20dB
  • Power source: 2 x 1.5V (AAA) batteries or 5V micro USB power source (cannot be powered by USB power banks with low-current shutoff)
  • Weight & Dimensions: 3.2oz; 2.7 x 4.1 x 0.9″

Package Contents: Just Mixer, 2 x AAA batteries, pouch, manual

Additional information

Weight 114 kg
Dimensions 2.4 × 6.8 cm
Item Weight

‎114 g

Product Dimensions

‎10.5 x 2.4 x 6.8 cm; 114 Grams


‎2 AAA batteries required.

Item model number




Connector Type


Hardware Interface


Region of Origin


Country Produced In


Mixer Channel Quantity


Battery type


Power source type

‎Corded Electric,Battery Powered


5 Volts



Date First Available

19 December 2019


Maker hart

10 reviews for JUST MIXER Audio Mixer – Battery/USB Powered Portable Pocket Audio Mixer w/ 3 Stereo Channels (3.5mm) Plus On/Off Switch

  1. Amazon Customer

    When I initially bought this, I was sceptical because of reviews claiming that there is a constant hiss. However, I knew there is an easy fix for this issue, a ground loop noise isolator. They can be found on Amazon for 15 SGD and are worth every penny. I hooked one up to the output and haven’t had any background noise/hiss!This unit has been outstanding otherwise. It can get loud, it has a sufficient amount of input ports and the volume sliders work like a charm. The only issue I found is that the gain knobs are useless as they will distort the audio outside of a frequency threshold. Overall, it’s a great little device to hook up audio from my phone, tablet and computer to my headphones.

  2. TONE

    All good
    Does what it says on the tin. Great mini mixer. Size does matter.

  3. Skip Hunt

    UPDATE: A fun mixer that works well, even off AAA batteries. Fairly quiet too – Recommended 🙂
    UPDATE2: Well, this mixer is working perfectly well now. And, I can’t replicate any of the problems I was having with this mixer when I first got it. I was getting tons of noise when running off batteries, didn’t matter if they were rechargeable or alkalines, and the USB power pack I was running it off of kept shutting down.The seller was responsive as well and assured me that they stand behind their products.I’ve hooked up this mixer nearly a dozen times now… used an assortment of different cables, mics, aux inputs. I’ve used it on an iPhone SE and an iPad Pro. Everything has worked perfectly. I CAN get a little bit of noise if I have the mixer sitting right next to the iPhone when they’re hooked up together… but nothing like I was getting before.No clue why it’s working now, or why it wasn’t at first. The best speculation I’ve got is that when I first unboxed it, and then plugged in the first 3.5mm mini cables into it’s 1 & 2 channels, there was some rough resistance. They didn’t go in smooth like you’d expect. They do now, but I’m wondering if there was maybe a bit of metal that didn’t get finished out inside one of the ports that got knocked free and was causing some kind of short circuit situation? No idea, but now that it’s been working perfectly without any hint of the initial problems I experienced, and that now that I know the seller stands behind the product… I don’t have any reservation giving this a solid 5-stars. It works well, it’s affordable, it’s lightweight, easy to use, and functions well off AAA batteries. I’m even having good luck with rechargeable AAAs. Recommended! :)___UPDATE: The seller got back to me quickly and offered to give me a small discount after returning/refunding to Amazon then rebuying the mixer. However, after lots of testing yesterday before concluding something was definitely wrong with this mixer… all of the problems went away after reconnecting everything later at a coffee shop. Then later in the evening at home, it was still performing flawlessly. And later in the night, I tried again… did everything exactly the same as before… but nothing would repeat the same failures I’d experienced. Even running it off Ni-MH rechargeable AAAs was perfectly quiet. Earlier, the Just Mixer was shutting off my USB battery pack as well. I’d assumed it was an auto–shutoff in the pack… and it was shutting of due to low power drain, but even that has stopped. The mixer works fine and I’m unable to reproduce the problems I was having before.I’m hesitant to give this more stars yet, in case the mystery problems promptly reappear. But I’ll bump it up to 2-star until I’m certain the problems were just a rare fluke. If it’s still working fine in a week or so, I’ll update the review accordingly.___Hello,I bought this mixer a couple weeks ago. The blue one. I’m getting a lot of noise when run off batteries. At first, I thought it was because I was using rechargeable 1.2v Ni-Mh batteries… so as you recommend on your product page, I tried brand new Energizer 1.5v AAA alkaline batteries. Still there’s noise. When I’m using the mixer off USB or a USB battery pack, there’s no noise at all. ONLY when using AAA batteries.Is there something wrong with this mixer? Would you like to send me a replacement? Or, should I get a refund from Amazon for this?I bought this MOSTLY because it’s says it runs off of AAA batteries. If it can’t function without excessive noise while running off AAA batteries alkaline OR rechargeable.. it’s useless to me.

  4. Vap

    Mete ruido
    No me gustó, metía interferencia con todo. Tuve que devolverlo.

  5. Amazon Customer

    Exactly what I needed
    This product perfectly solved a problem I’ve been struggling with for a long time. For background I know NOTHING about how audio tech works. I play a multiplayer video game that doesn’t have native voice chat because it’s on the Nintendo switch. In order to communicate with people I’m playing with I have to use discord on my laptop. What I needed was a way to listen to the game audio and my laptop audio at the same time. The solutions online involved running the switch audio directly into the computer, and this just did not work no matter the quality of the wires, adding a ground loop isolator (don’t even know what that is, someone told me it could help), separating power supplies, which made the set up awkward and inconvenient. Even when I could minimize the static the audio quality was still terrible and there was a very noticeable delay.Okay, so after a bit of roaming around online I decided to give this little gadget a try. It works PERFECTLY for my needs. Granted, mine are not professional or audiophile needs. What I know is that the device is small and runs on batteries, which makes one less wire to organize. I run one 3.5 mm cable from my switch’s headphone jack to the mixer, and another 3.5 mm cable from my laptop’s headphone jack to the mixer, plug my headphones into the mixer, and voila – with a little fiddling with the volume dials I can hear my game audio and computer audio exactly the way I want. I bought a cheap USB microphone that sits in front of me on my desk to capture my voice, and I’m good to go. Finally!

  6. RC

    Does the trick nicely for my portable rig for teaching fitness classes
    So teaching some fitness classes outside and didnt want to rely on lugging equipment from the gym around and running a power line. My quarantine project was converting a cheap Restoration Hardware powered single speaker box into a little 2.1ch powerhouse with a 6.5″ sub, 6.5″ mids and 1″ tweeters with much more power, clarity and oomph all running off of a 20v B&D power tool battery.I didn’t really like the amplifier boards with the built in mic from a quality point of view, and none were 2.1, so it would’ve taken a but more work to make that work in a small 12″ cube. So this seemed like the perfect option to add in my mic.Have my phone plugged in via the aux input and the mic plugged into input 1. I power the mixer with a 10k mah Samsung battery pack. And while it doesn’t draw enough power to keep the pack on by its own, toy just plug in another USB cable and charge your phone at the same time. Battery pack shut off problem solved, and my phone charges as well. The mic is all battery powered so nothing plugged in.It does take some playing around to get the levels where you want them. For me, the mic gain is at 9 o’clock and mic volume at about 30%. I’m sure your mileage may vary.With music cranked everything works perfectly. No issues whatsoever. Just did a dry run of my 1hr class with no issues overall.Now with nothing playing there is some background buzz, but I’m fine with that. And I’m sure I could try a ground loop isolator, but I don’t want to lessen the overall sound. Might try ferrite cores. Or I might just not do anything and spend whatever funds on finishing the cube’s big brother in the picture, qbomb dual 8″ sub enclosure with a pair of 8″ goldwood coaxial speakers. Those goldwood’s like to breath, so they needed a big box. Should be good for outdoor movies as well.

  7. The Gongs

    Looks great. Sounds terrible.
    I ordered the blue. Its very nice looking and seems well built. But there are a couple of of issues. The USB power port on the side is not a good design. It would be much better if it were on the rear of the unit. But that is only a minor complaint. The big problems are five-fold.1. This unit is hella noisy. Signal to noise ratio is very low. There is a constant hiss present irrespective of cable quality, lengths, or signal quality/dBv.2. Receives LOTS of electronic interference from nearby devices. If u keep the cables short and everything away from the device, it was acceptable. Again this was observed irrespective of quality of the cable used. Additionally, if using USB power source, you MUST use a USB wall plug. If plugged into a computer there is a lot of interference (am radio seemingly as I was listening to a prayer request radio show).3. Zero headroom at line level. Headphone level input? Forget about it. Line level clips at unity gain (slider) with gain knob all the way down. Just no headroom at all. And I’m not even using this to boost the signal, just to mix at unity gain or less.4. Cross-talk between channels. Not much but it’s there….which is partly due to problem 5 below…5. Even at negative infinity slider position, signal is NOT mute. Signal still leaks through.So over all:Great price & look but poorly considered placement of USB port. Terribly functional quality all around.Update:This product has deteriorated in the week that I have owned it. It is too noisy for any kind of real use. Unfortunately, even it’s very nice appearance cannot make up for it’s terrible performance. I am revising my 2 star review to 1 star.2nd Update:Due to EXCELLENT customer service by the seller, I have to believe that my unit may have been faulty. You can’t offer excellent customer service unless your product is at least decent. Otherwise a company would spend all of it’s resources putting out fires (figuratively… LOL… this thing did not catch fire). Anyway, given all of the other 4 and 5 star reviews and the seller’s excellent customer service, I am revising my rating to 3 stars. For a full description of the problem I encountered and the application in which this mixer was used, read the replies to this review. If your setup is less complex (most will be) you may experience a much better end result even if my unit was not faulty.


    Need to use a proper power bank or it gets way too noisy
    I was wrong in my previous review. I gave this thing 3 stars because it was very very noisy. I use it at the end of my pedalboard to connect my guitar and a bluetooth receiver to play backing tracks from my phone and practise. Sometimes I record my practice sessions as well.The power bank I intended to use at first, a Xiaomi Mi 20000Mah power bank, would switch itself off as the mixer does not draw enough power to keep it on. So I used a couple of old cheap power banks I had sitting around and they worked well as they don’t have the auto-switch off feature. There was a lot of white noise when I turned up the volume and I thought it was because of the device itself, hence my previous review.I figure out a way to override the auto-power off function of the MI power and voila! the noise disappeared!So I am so changing this to 5 stars.The best feature is that you can pan the two stereo inputs. This is the reason why I bought this in the first place as I can pan the guitar to either channel and make it cut through the mix for quick recordings. Although the knob is not very sensitive, it is enough for quick recordings.I can now recommend this product but use a proper power bank. The one I use now is made with polymer batteries? maybe that is the reason…

  9. Giovanni Pani

    Otiimo in tutto: consegna e articolo.

  10. Ondra

    Solid 3.5mm jack mixer
    I bought this mixer so that I could mix sound coming from my Nintendo Switch with Discord voicechat from my PC without the need for expensive audio equipment and it fullfills that role quite well. It’s been over a year and a half now of almost daily use and it still delivers solid sound without any real issues. The volume can be controlled for each of the two main audio sources with a nice slider, and there is a “master” one that allows you to easily control volume of the output as well. In addition to this, all audio sources have a gain knob, which allows you to artificially increase the volume in case the source is too silent. This can however reduce the sound quality and produce what is know as “clipping”, which is what the red LED titled “over” is for. It lights up every time the output is getting distorted by clipping, so that you easily know how much gain is too much. If I had one complaint about this product, it would be that the jacks are pretty sensible — one bumb into the unit can make the output go buzzing until you turn the jacks into the exact position they were in before, which can be a bit annoying. I am not sure if it’s not a feature of the 3.5mm jack rather than a flaw of the product though, which is why I won’t reduce any stars for this “feature” (?). I have seen some complaints over the audio quality when feeded from PC USB, but that seems to be related to the power source rather than the product itself. I am feeding my unit from wall outlet using 2A microUSB charger and the audio quality is pretty solid. Overall, this is a reliable, quality product and a great purchase for the price.

Add a review

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.