TOBH v2.5 Rebuildable Dripping Atomizer Review
The TOBH is hands down the best atomizer I have ever tried, but it is definitely not without its quirks and faults. I have the TOBH v2.5, but since there have been no major changes between revisions (except of course the v3 which is a larger diameter designed for 26650 mods), just about everything I say about the v2.5 also applies to the older versions.
The heat sink on the top cap is quite effective. Even with very low resistance builds ( > 0.2 ohms) and using a metal drip tip without an insulator, the tip has never gotten uncomfortably hot. The two-piece design, with a sleeve and a separate top cap, makes it easier to drip compared to one-piece designs which require you to remove the entire cap (I do not use wide-bore drip tips which allow you to directly drip through). And the conical shape of the top cap helps reduce the chamber size, enhancing flavor. It also smooths out the airflow, a character which is difficult to describe, but I find to be very noticeable when switching back and forth amongst my other drippers.
With the high-temperature o-rings and insulators, there's no need to worry about anything melting when pulsing the coils for positioning or burning off residue.
The post holes are plenty large enough for thick wire. Two strands of 22 gauge Kanthal easily fits in the center post hole, and although I have not tried it myself, some people have even reported that four strands of 22 gauge wire will fit.
The entire base, including the negative posts, are machined from a single piece of steel, making it extremely strong and durable. It also helps lessen the electrical resistance of the atomizer itself, which is further aided by the solid copper positive contact.
The drip well is deep enough to hold a decent amount of juice, although I would have preferred it to be just a little bit deeper. Another 1.0 - 1.5 mm would be perfect.
Airflow is excellent, with a total of six 5/64" (2.0 mm) air holes, three on each side of the sleeve. Airflow adjustment is crude but effective, with a raised tab on each side of the deck that blocks off the air holes depending on how the sleeve is positioned.
Unfortunately, the airflow system is the major fault in the design of the TOBH atomizer. The airflow adjustment tabs are right in front of the center (positive) post, making a center post build inefficient. It takes some creativity and experimentation to figure out a good way to mount the coils to get proper airflow.
After several attempts, my favorite build is to offset the coil at an angle, placing it between the airflow tab and the negative post, parallel with the closest edge of the deck and directly behind the airflow holes on the sleeve. The easiest way to do this is to bend one leg right next to the coil, and wrapping it around the negative post under the screw, while bending the other leg 45 degrees a few millimeters away from the coil, aligning it into the center post hole.
Here is a 24 gauge dual coil build, which metered out to 0.32 ohms -- pretty low resistance but nothing too crazy for my Sony VTC4 and VTC5 batteries.
Before installation:
After installation:
The airflow design also means that juice can leak. The tabs are not wide enough to close all of the air holes, and even if they were, the sleeve is a very tight fit. It is nearly impossible to rotate the sleeve when it is attached; instead you must remove the sleeve and realign it in order to adjust the airflow. Because of this, the TOBH atomizer is basically useless for me while out and about. It is delegated strictly for in-home use only since juice will leak out into my pocket
An airflow adjustment ring on the outside of the sleeve would fix this. My Helios atomizer uses this design, allowing me to quickly and easily adjust the airflow, or close it up completely, with a simple twist of the ring. Using this type of system would also eliminate the need for the airflow tabs, allowing more options for coil placement.
Also due to the design of the airflow adjustment, the TOBH is only suitable for dual coil (or quad coil) builds. I tend to prefer single coil builds, but like to switch frequently between single and dual coils. When I want a single coil build, I just need to put a small piece of electrical tape on the outside of the sleeve to block one of the two sets of airflow holes. This is no big deal, and is a problem shared by nearly all RDAs with two sets of airflow holes.
The final change I would like to see is also something found on the Helios. It's split ('T'-shaped) positive post gives you four post holes, allowing dual coil builds as easy as a single coil build, and quad-coil builds as easy as dual coil builds, compared to a standard 3-post atomizer. Since the positive post can be quickly removed by unscrewing the copper positive contact on the 510 connection, the ideal scenario would be to include both a standard positive post and a split positive post, allowing the choice of either, since the extra space required by the split post might negatively affect airflow in the smaller chamber of the TOBH compared to the Helios.
These aren't major changes, but they would make major improvements to an already excellent atomizer. Even without the split positive post, the Helios-style airflow design would instantly solve the major issues (the removal of the airflow control tabs for more options as per coil placement, and the ability to effortlessly "close" the top cap, preventing juice leaks and making the TOBH suitable for use on the go).
With all the said, I am very, very happy with my TOBH v2.5. Implement the design changes I suggested above and it will be an absolutely remarkable atomizer, with nothing else even coming close to its usability and performance.
The TOBH is hands down the best atomizer I have ever tried, but it is definitely not without its quirks and faults. I have the TOBH v2.5, but since there have been no major changes between revisions (except of course the v3 which is a larger diameter designed for 26650 mods), just about everything I say about the v2.5 also applies to the older versions.
The heat sink on the top cap is quite effective. Even with very low resistance builds ( > 0.2 ohms) and using a metal drip tip without an insulator, the tip has never gotten uncomfortably hot. The two-piece design, with a sleeve and a separate top cap, makes it easier to drip compared to one-piece designs which require you to remove the entire cap (I do not use wide-bore drip tips which allow you to directly drip through). And the conical shape of the top cap helps reduce the chamber size, enhancing flavor. It also smooths out the airflow, a character which is difficult to describe, but I find to be very noticeable when switching back and forth amongst my other drippers.
With the high-temperature o-rings and insulators, there's no need to worry about anything melting when pulsing the coils for positioning or burning off residue.
The post holes are plenty large enough for thick wire. Two strands of 22 gauge Kanthal easily fits in the center post hole, and although I have not tried it myself, some people have even reported that four strands of 22 gauge wire will fit.
The entire base, including the negative posts, are machined from a single piece of steel, making it extremely strong and durable. It also helps lessen the electrical resistance of the atomizer itself, which is further aided by the solid copper positive contact.
The drip well is deep enough to hold a decent amount of juice, although I would have preferred it to be just a little bit deeper. Another 1.0 - 1.5 mm would be perfect.
Airflow is excellent, with a total of six 5/64" (2.0 mm) air holes, three on each side of the sleeve. Airflow adjustment is crude but effective, with a raised tab on each side of the deck that blocks off the air holes depending on how the sleeve is positioned.
Unfortunately, the airflow system is the major fault in the design of the TOBH atomizer. The airflow adjustment tabs are right in front of the center (positive) post, making a center post build inefficient. It takes some creativity and experimentation to figure out a good way to mount the coils to get proper airflow.
After several attempts, my favorite build is to offset the coil at an angle, placing it between the airflow tab and the negative post, parallel with the closest edge of the deck and directly behind the airflow holes on the sleeve. The easiest way to do this is to bend one leg right next to the coil, and wrapping it around the negative post under the screw, while bending the other leg 45 degrees a few millimeters away from the coil, aligning it into the center post hole.
Here is a 24 gauge dual coil build, which metered out to 0.32 ohms -- pretty low resistance but nothing too crazy for my Sony VTC4 and VTC5 batteries.
Before installation:
After installation:
The airflow design also means that juice can leak. The tabs are not wide enough to close all of the air holes, and even if they were, the sleeve is a very tight fit. It is nearly impossible to rotate the sleeve when it is attached; instead you must remove the sleeve and realign it in order to adjust the airflow. Because of this, the TOBH atomizer is basically useless for me while out and about. It is delegated strictly for in-home use only since juice will leak out into my pocket
An airflow adjustment ring on the outside of the sleeve would fix this. My Helios atomizer uses this design, allowing me to quickly and easily adjust the airflow, or close it up completely, with a simple twist of the ring. Using this type of system would also eliminate the need for the airflow tabs, allowing more options for coil placement.
Also due to the design of the airflow adjustment, the TOBH is only suitable for dual coil (or quad coil) builds. I tend to prefer single coil builds, but like to switch frequently between single and dual coils. When I want a single coil build, I just need to put a small piece of electrical tape on the outside of the sleeve to block one of the two sets of airflow holes. This is no big deal, and is a problem shared by nearly all RDAs with two sets of airflow holes.
The final change I would like to see is also something found on the Helios. It's split ('T'-shaped) positive post gives you four post holes, allowing dual coil builds as easy as a single coil build, and quad-coil builds as easy as dual coil builds, compared to a standard 3-post atomizer. Since the positive post can be quickly removed by unscrewing the copper positive contact on the 510 connection, the ideal scenario would be to include both a standard positive post and a split positive post, allowing the choice of either, since the extra space required by the split post might negatively affect airflow in the smaller chamber of the TOBH compared to the Helios.
These aren't major changes, but they would make major improvements to an already excellent atomizer. Even without the split positive post, the Helios-style airflow design would instantly solve the major issues (the removal of the airflow control tabs for more options as per coil placement, and the ability to effortlessly "close" the top cap, preventing juice leaks and making the TOBH suitable for use on the go).
With all the said, I am very, very happy with my TOBH v2.5. Implement the design changes I suggested above and it will be an absolutely remarkable atomizer, with nothing else even coming close to its usability and performance.
