Lately, JayBo has been on a roll, pumping out new atomizers with an interesting take on current designs; the Inde Duo came out recently and now he’s at it again with the Theorem. With assistance from Matt of Suck my Mod, the Theorem is a top-coil RTA that features rear-side airflow as well as top airflow and comes with two pre-wicked stainless steel NotchCoils. Vaping360 has seen rear-side airflow in a top-coil RTA with the Avocado, but never have we seen one that includes top airflow as well. These are my two favorite airflow styles since they tend to produce fantastic flavor and to have them all in one atomizer is almost too good to be true. Is the Theorem really as awesome as it sounds? Let's find out.
The overall build quality is what you might expect from a $32 atomizer, it doesn’t feel cheap, but it also doesn’t feel like it’s any more expensive than it is. The deck o-rings are very tight which prevents leaking from the tank. The top cap o-rings are a bit loose and the drip tip o-rings are a tad tighter; this is good because it makes it easy to refill, but is also bad because you need to take the drip tip out in order to adjust the airflow. If you re-fill more than you adjust the airflow, then it’s not a problem, but if you like fiddling with the airflow on the go, this will add an extra annoyance to the process. I didn’t find any cosmetic defects and the atomizer was clean and ready to go right out of the box.
The build deck is a relatively standard split center-post design with one large slot for the positive-terminal. This is very similar to the Indestructible RDA, but on the negative-posts, the slots have been replaced with holes which should make mounting coils a bit easier. The positive-terminal stands quite a bit taller than the negative-posts which allows for both single horizontal as well as dual vertical builds. The wick holes are large half-circles which allow you to place the wicks into the tank before sliding on the outer sleeve.
Building the Theorem is pretty straightforward due to the familiar split-center post deck. One thing I don’t like is the slot in the positive-block; it requires you trap the leads under the screws. It isn’t really that difficult, but certainly not as easy as having holes. I don’t see the point of this; the screws only cover about 50% of the width of the slot so it won’t necessarily allow you to put in wider wire. There are several ways they could’ve improved this design: they could’ve used two slots instead a large one or they could’ve implemented a clamp system like a few other modders have been doing recently.
The tank might seem like it holds a lot but with the way this thing guzzles juice, it really doesn’t. I found that even at 24 watts, I could barely make it an hour drive without needing a refill. It’s almost like it’s a dripper with a huge well rather than an RTA.
Wicking is pretty straightforward but may be a little tricky if you've never built a top-coil RTA before. Since the wick holes are actually half circles, you don’t have to fiddle with shoving them down through holes in the deck. However, you must make sure the wick tails don’t touch the bottom of the tank and also make sure the tails are thinned out by cutting them at angle. You want the widest part of the wick to be in the coil and then gradually get slimmer towards the ends; this will optimize wicking. If you leave the wick holes too loose, you will end up with leaking issues; if they are too tight, you’ll end up with wicking issues. I seemed to have an easier time with wicking on the Avocado. I think this is because the wicks are pressed up against the tank most of the length as where the Avocado allows the wicks to hang freely in the tank.
One thing I do appreciate about this design is how the tank is held on by o-rings, this makes cleaning a breeze. I never had any leaking issues from the tank, but if held upside down or set on it’s side for a long period of time, it can leak out the drip tip.
[youtube https://www.youtube.com/watch?v=f4soQxOJH4w ]
The Theorem features both top airflow and rear-side airflow and is possible to use either option by itself or simultaneously. Adjusting the airflow is a real pain though. First you must remove the drip tip, then unscrew the washer that holds the airflow control ring in place, then make your adjustments. You then have to hold the airflow control ring while screwing the washer back on or else it may move around due to the friction caused by that final turn of tightening it. This may not be a problem if you like to set it and forget it, which I normally do, but since I like to experiment with it first to find the best configuration for me, I found this to be a chore. As stated in the Machining/Fit and Finish section, the drip tip o-rings are a bit tighter than the top cap o-rings so I found myself frequently removing the entire top cap on accident. You have to hold the top cap down while pulling on the drip tip to overcome this, yet another annoyance. In order to use both rear-side airflow and top airflow together, you need to remove the single airflow ring and use the dual airflow ring; not something that can be done on the go unless you carry the other ring with you.
Another thing I didn’t really like was how the rear-side airflow is set up: it is a large slot that sits behind the center-post. This causes the airflow to be less direct and results in loss of flavor. It also makes it difficult to figure out exactly where the coil should be in order to position it for best flavor.
Another thing to note is when you try to take the atomizer off a mod, you may accidentally mess up the airflow since there is not much to grab on to. I found myself grabbing the top cap section to twist (rather than the tank in fear of breaking the glass) which would cause the airflow control washer to loosen, disturbing the position of the airflow control ring.
With all of that aside, there is an extremely wide range of airflow configurations that should allow just about anyone to find a draw they like, including mouth-to-lung vapers.
Out of the box, there are two different aesthetics you can choose from: a transparent look with the glass sleeve or a more standard, yet sleek look with a juice level view. The glass sleeve is nice because it allows you to see the coils but for some, it may be too much to look at. The stainless steel sleeve looks great since it has no logos on it and the juice level view is not only a useful feature, it also adds a bit more style to what would’ve been a plain and boring looking steel tank. I really like how the lines reference the design of the NotchCoil as well. Personally, I think both sleeves look nice.
When you get the Theorem, there will be a pre-wicked NotchCoil already installed. However, the cotton is way too long to wick efficiently so you will need to cut each wick tail in half. After doing that, I still had wicking issues, even firing the 0.25 ohm coil at 30 watts. That prompted me to rewick it with a scottish roll wick. After doing that, it wicked just fine, even up to 60 watts. However, at 46 watts and above, the drip tip gets really hot in the middle of a hit. Since it’s glass, it cools down quickly but long drags aren’t really possible without burning your lips at higher wattages.
So I put in one of my favorite builds for top-coil RTAs: a single 26g kanthal coil with 10.5 wraps around a 3 mm screwdriver that came out to 1.34 ohms. Firing it around 24.2 watts, I noticed it’s a bit cooler vape than the Avocado, most likely due to the larger chamber and the airflow being more indirect. The flavor was also not as good as I was expecting.
Then I put in a single 24g kanthal coil with 9.5 wraps around a 3 mm screwdriver that came to around 0.80 ohms. Firing that at 34 watts, the flavor was a bit better. This prompted me to play around with coil position. I found the higher the coil is, the warmer the vape will be. Lowering it will cool the vape but will put out more flavor, up to a certain point. If you position the coil too low, then you will not get enough airflow to the bottom of the coil and the flavor will be muted.
I also tried out a dual vertical build using 26g kanthal that came to 0.66 ohms. I would say the overall performance was about the same as the single 24g kanthal build. In general, this atomizer performs best between 30 and 50 watts and I got the most flavor from the NotchCoil.
I was very excited to try the Theorem when I saw the preview of it on Suck my Mod’s YouTube channel due to how much I loved the Avocado. I wouldn’t say the Theorem is bad, it just has issues that Avocado doesn’t. Overall, I think the Avocado provides better flavor and a better overall experience and since they’re both around the same price, I would steer anyone looking for a good, affordable top-coil RTA in the direction of the Avocado instead of the Theorem.