MadLab MLP105 Junior Theremin Kit Review: DIY Musical Magic or Technical Headache?

There is something inherently mystical about the Theremin. As one of the earliest electronic instruments, its ability to produce sound without any physical contact has fascinated musicians, scientists, and hobbyists for nearly a century. We recently found ourselves diving down a rabbit hole of DIY electronics, looking for a project that could bridge the gap between basic soldering practice and functional musical synthesis. The problem many beginners face is the sheer complexity of most synthesizer builds. If you jump straight into a modular rig, you are often met with overwhelming schematics and expensive components that can be ruined with a single shaky solder joint. This is where the MadLab MLP105 Junior Theremin Kit enters the picture. It promises an accessible entry point into the world of electronic music, but as we discovered, the journey from a bag of parts to a working instrument is filled with both rewarding “aha!” moments and frustrating hurdles that every potential builder needs to understand before picking up their soldering iron.

What to Consider Before Buying a Synthesizer & Workstation Keyboards Kit

A Synthesizer & Workstation Keyboards kit, even a “Junior” version like the MadLab MLP105 Junior Theremin Kit, is more than just an item; it’s a key solution for those looking to understand the fundamental physics of sound and electromagnetism. Instead of simply buying a finished product where the magic is hidden inside a plastic shell, a kit forces you to interact with the oscillators, capacitors, and integrated circuits that make synthesis possible. This hands-on approach builds a level of technical literacy that stays with you long after the project is finished. However, it requires a specific mindset—one that values the process of creation as much as the final output. Without this perspective, the nuances of assembly can feel like a chore rather than a learning experience.

The ideal customer for this type of product is someone facing a curiosity about electronic components or a musician looking for a unique, lo-fi addition to their setup. It is also a fantastic choice for the paranormal investigation community, where these circuits are often repurposed into REM pods. However, it might not be suitable for those who have no experience with a soldering iron or those who expect a high-fidelity, concert-ready instrument out of a $20 bag of parts. If you are looking for a professional-grade performance tool with pitch correction and MIDI out, you might consider more advanced, pre-built alternatives.

Before investing, consider these crucial points in detail:

• Dimensions & Space: When dealing with DIY kits, you need to consider not just the final size of the product—which in the case of the MadLab MLP105 Junior Theremin Kit is incredibly compact—but also the space required for your workstation. You will need a clean, well-lit area with room for a soldering station, a multimeter for troubleshooting, and a way to secure the small PCB while you work.
• Capacity & Performance: In the world of “Junior” kits, performance is measured by sensitivity and stability. You want a kit that provides a noticeable pitch shift when your hand approaches the antenna. We found that the performance of this specific kit is highly dependent on the quality of your power source and the precision of your component placement.
• Materials & Durability: Look closely at the quality of the PCB (Printed Circuit Board). A good board has clear labeling and high-quality copper traces that won’t lift if you accidentally apply too much heat. The MadLab MLP105 Junior Theremin Kit utilizes copper as its primary body material for the sensing elements, which is excellent for conductivity but requires careful handling to avoid oxidation.
• Ease of Use & Maintenance: While the “Junior” moniker suggests simplicity, you must account for the long-term maintenance of the device. Since it is an open-circuit design, it is susceptible to dust and physical damage. Consider whether you plan to build a custom enclosure to protect the delicate components and how easy it will be to swap out the 9V battery over time.

While the MadLab MLP105 Junior Theremin Kit is an excellent choice for a weekend project, it’s always wise to see how it stacks up against the competition in the broader world of synthesizers. For a broader look at all the top models, we highly recommend checking out our complete, in-depth guide:

First Impressions and Key Features of the MadLab MLP105 Junior Theremin Kit

Unboxing the MadLab MLP105 Junior Theremin Kit is a humble experience. You aren’t met with sleek foam inserts or a glossy manual; instead, you get a small, transparent bag filled with the building blocks of an instrument. It feels like a throwback to the classic electronic kits of the 80s and 90s. The kit includes a compact PCB, a handful of resistors, capacitors, a piezo sounder, and two vital integrated circuits (ICs). One of the first things we noticed was the lack of a physical antenna in the traditional sense; rather, the kit relies on copper plates or wire extensions that you must configure yourself. It is a bare-bones approach that invites customization from the very beginning.

Assembly is where the “Junior” label gets tested. We found that while the component count is low, the board is quite tight. You’ll want to see its full feature set and user reviews to prepare for the specific components included. Compared to market leaders in the educational space, MadLab (under the Velleman umbrella) focuses more on the raw circuit rather than a polished “toy” feel. This is a real synthesizer, albeit a simple one, and it behaves as such. The initial look is industrial and raw, which we personally loved, but it might be intimidating for a parent hoping for a “snap-together” experience for their child.

A Deep Dive into the MadLab MLP105 Junior Theremin Kit’s Performance

The Assembly Experience: A Test of Skill and Patience

When we sat down to build the MadLab MLP105 Junior Theremin Kit, we approached it with the confidence of seasoned DIYers. However, the “Junior” tag can be a bit of a misnomer if you aren’t careful. The assembly process is a classic through-hole soldering project. The PCB is well-etched, but the labels for the integrated circuits—specifically IC1 and IC2—can be confusing. We found that you must pay extremely close attention to the orientation of the chips. As some users have noted, installing a chip backward or swapping the 555 timer with the PIC microcontroller will result in a circuit that either does nothing or, worse, causes the voltage regulator to get dangerously hot. To avoid this, we recommend you check the latest price and availability and perhaps pick up a spare kit if you are a total novice, just in case a component is heat-damaged during your first try.

The soldering itself is straightforward if you have a fine-tip iron. The pads are close together, so bridge-checking with a multimeter is a mandatory step before you ever connect that 9V battery. We spent about 45 minutes on the build, taking our time to ensure every joint was a perfect “tent” shape. One detail that really sets this kit apart is the self-test feature. When you first power it on, the LED should flash and the piezo should chirp. If it doesn’t, you know immediately that something is wrong. We found this feedback loop invaluable for troubleshooting, even though we’ve seen reports from other users where the self-test failed due to faulty capacitors right out of the bag.

Sensitivity and Sound: The Core Theremin Experience

Once assembled and tested, the performance of the MadLab MLP105 Junior Theremin Kit is surprisingly punchy for its size. This isn’t a Moog; it produces a raw, square-wave-adjacent tone that sounds like a vintage sci-fi movie. The pitch is controlled by the proximity of your hand to the sensing wire or plate. We found the circuit to be incredibly sensitive—sometimes too sensitive. It reacts to the movement of anyone in the room if the sensitivity is tuned a certain way. This is a double-edged sword: it makes for a very expressive (if chaotic) instrument, but it can be difficult to “play” a specific melody.

In our evaluation, the sound quality is exactly what you would expect from a piezo sounder—thin and buzzy. However, the magic happens when you start hacking the output. We experimented with bypassing the piezo and sending the signal to a small amplifier, which revealed a much richer, grittier texture. For those using this as a musical tool, we highly recommend looking into the technical specs to learn more about the output impedance and how to safely hook it up to external speakers. The way the pitch slides and warps as you move your hand is a tactile joy that pre-built digital synths often fail to replicate.

Repurposing for the Paranormal: The REM Pod Factor

One of the most fascinating aspects of the MadLab MLP105 Junior Theremin Kit is its popularity outside of the music world. We cannot review this product without acknowledging its status as the “engine” for many DIY REM pods used in ghost hunting. Because the circuit is designed to detect changes in the electromagnetic field around its antenna, it is perfect for detecting “anomalies.” We tested this by setting the kit on a stable surface and observing how it reacted to various electronic devices being brought near it. It is remarkably consistent in this regard.

We found that by adding a secondary switch—a common modification suggested by users—you can disable the sound while keeping the LED indicators active. This is crucial for “EVP sessions” where you don’t want the buzzing of a Theremin to drown out potential audio recordings. The fact that such a low-cost kit can serve as a powerful tool for a specialized hobby is a testament to the versatility of its design. If you are a paranormal investigator, this is likely a feature that really sets it apart from buying a pre-made REM pod that might cost five times as much for essentially the same circuitry.

Reliability and Quality Control: The “Hit or Miss” Reality

As experts, we have to be honest: the MadLab MLP105 Junior Theremin Kit has some significant quality control issues that you need to be aware of. During our research and testing, we encountered the same frustrations voiced by many users: missing parts and defective components. It is not uncommon to open a kit and find two 555 timer chips but no PIC, or to find that the electrolytic capacitors are missing entirely. This is likely a result of the high-volume manufacturing process in China, but it is a major drawback for a “Junior” kit where the builder might not have a bin of spare parts to pull from.

Furthermore, the issue of the voltage regulator or transistor getting “too hot to touch” is a recurring theme. This usually points to a short in the circuit or a faulty component provided in the kit. While we were able to get our unit working perfectly on the first try, we recognize that our experience isn’t universal. If you decide to take the plunge, we suggest you check the latest price and user reviews to see if the recent batches have improved. The “hit or miss” nature of the kit means you should be prepared to do some multmeter work and potentially source a replacement capacitor or two if your kit arrives with “junk” components.

What Other Users Are Saying

The general sentiment surrounding the MadLab MLP105 Junior Theremin Kit is starkly divided between those who see it as a brilliant, budget-friendly project and those who feel burned by manufacturing errors. We found a strong community of builders who absolutely swear by these for “inexpensive rempods,” with one user noting they used a 3D printer to create custom plates and added switches for silent operation. This “maker” crowd appreciates the kit for exactly what it is: a cheap, functional circuit that is ripe for modification. “Works great as a low budget yet powerful REM pod,” one user shared, echoing our own findings regarding its sensitivity.

On the flip side, the negative feedback is almost exclusively focused on missing or defective parts. We saw multiple reports of “0 stars if I could” due to missing PIC chips or regulators that overheated immediately. One user expressed deep disappointment after their third attempt to get a working kit, stating it “used to be a reliable brand” but now suffers from poor quality control. Another user warned that there is “nothing JR about this,” citing the confusing instructions and defective parts as a barrier for children. This feedback is critical because it highlights that while the circuit design is solid, the packaging and fulfillment process can be a gamble.

Comparing the MadLab MLP105 Junior Theremin Kit to Top Alternatives

1. KORG MicroKorg2 Synthesizer/Vocoder

The KORG MicroKorg2 is in a completely different galaxy than the MadLab kit. While the MadLab is a DIY project for learning and basic sensing, the MicroKorg2 is a professional-grade workstation. It features a powerful virtual analog engine, a vocoder, and a built-in keyboard. Someone who finds the MadLab MLP105 Junior Theremin Kit too limited or frustratingly lo-fi should look here. It is for the musician who wants immediate, high-quality sounds and presets without the need for a soldering iron. However, you lose the educational value of building the circuit yourself, and the price point is significantly higher.

2. Arturia MicroFreak 25-Key Hybrid Synthesizer

The Arturia MicroFreak is perhaps the middle ground for those who love the “weirdness” of a Theremin but want modern stability. It features a PCB touch plate keyboard that, much like the MadLab kit, relies on capacitive touch and proximity. It is a hybrid synth with digital oscillators and analog filters. If you enjoyed the concept of the MadLab MLP105 Junior Theremin Kit but want a “real” instrument that can save patches and connect to a computer via MIDI, the MicroFreak is an unbeatable alternative. It captures that experimental spirit while providing a much more reliable and professional user experience.

3. MOOG Theremini Theremin with Pitch Correction

If you specifically want a Theremin but found the MadLab kit’s lack of pitch stability frustrating, the Moog Theremini is the answer. It takes the traditional Theremin concept and adds modern technology like pitch correction and a sound engine based on the Animoog. Unlike the MadLab MLP105 Junior Theremin Kit, which requires a steep learning curve to play a melody, the Theremini can be set so that it’s impossible to play a wrong note. It also includes a built-in speaker and a tuner. It is the perfect upgrade for someone who started with the MadLab kit and realized they wanted to take Theremin playing seriously as a musical discipline.

The Final Verdict: Is the MadLab MLP105 Junior Theremin Kit Right for You?

The MadLab MLP105 Junior Theremin Kit is a fascinating, frustrating, and ultimately rewarding piece of tech. It succeeds as an educational tool for those willing to get their hands dirty and troubleshoot the occasional missing resistor or confusing instruction. Its strengths lie in its extreme sensitivity and its “hackability,” making it a darling of the paranormal community and DIY synth enthusiasts alike. However, its weaknesses in quality control and the potential for component failure mean it isn’t a project you can just “set and forget.” It requires active engagement and a bit of technical grit.

In summary, if you are looking for a cheap way to build your own REM pod or want to spend a rainy afternoon learning how a basic oscillator works, this kit is a fantastic value. Just be sure to double-check your components against the manifest before you start. For those who want a guaranteed working instrument out of the box, we recommend looking at the alternatives mentioned above. If you’re ready to start your DIY journey, we suggest you grab the MadLab MLP105 Junior Theremin Kit here and keep your multimeter handy—it’s time to make some noise!