Not in the same class is the original Solo, but cheap & cheerful, has a con or two, packs an punch & somehow seems to perform adequately for both emesh and sub ohm use.
For emesh and sub ohm d-juice exploration, I believe the Original Geekvape Solo/Mini remains unbeatable for value & performance. But sadly, having been discontinued we can now expect supplies to gradually dry up (still widely available on UK Ebay at March 2025). Here I evaluate the Z50 as a cost-effective replacement for dimitri emesh and 'sub ohm'.
Note TCR of 92 for TC-SS default on earlier Z50s
Menu screens are stock Geekvape Aegis (Power, Bypass, VPC, TC-TCR, and TC-SS).
Earlier Z50s (inc firmware YK2021 0319 V01) have a default TCR value for the TC-SS setting of 92, compared to 105 for the Solo and later models of Z50 (inc firmware YK2022. 0214 V01) Theoretically, this means that for a correct reading of 200°C on a Geekvape Solo, a setting 225.4°C would theoretically be needed on the earlier Z50 to achieve the same actual temperature with an identical coil. Of course, by switching to TC-TCR mode with a TCR of 105, this removes the need to add this offset. (For workings to these calculations, see bottom of this page)
However, this is of less interest to me nowadays as I have completely abandoned temp control on this mod
TCR of 105 for TC-SS default on later Z50s. Many thanks to Zed for reporting & providing the pic
Ohms law in action During a "Fire Cycle" Volts x Amps = Watts
Max power rating is 50W, which appears fully warranted. From a fully charged battery, I continously chain-vaped an entire 3ml tankful of PG/VG in Power mode at full 50W. The Z50 became warm, the tank got hot, and dense vapour filled the entire room, but throughout, the indicated power stuck almost entirely at 50W with intermittent short dips to around 48.5.
Afterwards, the battery level indicated only 1 pip down, and it was still cheerfully throwing out what felt like a very punchy 50W. The Z50 is also capable of reaching its full power in TC modes, with about 48.5to 50W visible on the display during a hard blow onto the mesh. Thankfully, there is no sign of the L200 TC defect.
However there is another issue if using stainless steel coils. The Z50 applies a calculated Wattage based upon a single measurement of cold coil resistance. Unlike the original Solo, it doesn't measure/calculate throughout the fire cycle. This is fine for Kanthal and Ni80 coils (which don't increase resistance with temperature) but when using stainless steel coils (or any other with a significant TCR value), the actual power will quickly reduce as the coil heats up. For example, with a set power of 25W, using an SS316 0.3Ω coil in power mode, you can expect the actual coil power to fall by 3.6W within a couple of seconds of holding the Fire button.
For emesh as per the latest noobs suggestion, this will mean using a starting value of 20W (calculated 19.856) instead of the quoted 17W. But be aware that a sudden release and immediate re-press of the Fire button during a fire cycle will instantly force a re-calculation of the power, this time with a hot mesh, and the power will suddenly increment by the 3W offset.
The all-important coil reset procedure is a little different to the Solo/Mini, but works perfectly when performed as described here.
During "empty mesh" testing, the Z50 inspired little confidence in both "no toke" & "standard toke" tests (see the emesh update/troubleshooting video). However several live tests with 15mg loads actually felt reasonably smooth. At I write, I've conducted several runs with TC-SS settings of 180 to 215°C. These felt very slightly softer than the expected equivalent from my GeekVape Solo, but nevertheless produced an agreeable experience. It was only afterwards that it dawned on me about differences in TCR as mentioned above, so there's still scope for further tests with slightly higher temperatures. Edit 20 Jan 2023: I've now tested upto a setting of 235°C, which felt moderately hot and appeared to supercharge the intensity considerably
So far I'm reasonably impressed by this mod for dimitri use, albeit with the slightly annoying power mode anomaly described above. It's definitely no Original Geekvape Solo, but a low price (which of course includes a quality internal battery), ease of use, it can be a bargain.
It's physically small, so much that the Mesh Pro RDA (overhangs it by a mm or two) gives it a slighty top-heavy look & feel. It would certainly appear odd with larger sub ohm tanks, but who cares for dimitri use.
Some may be discouraged by the 50W maximum power, but be assured that at least on my own Z50, it's effortlessly achieved and apparently sustainable throughout chain-vaping without cut-out. For my own dimitri vaping, this capability is way more than adequate.
I haven't dismantled for build quality inspection, but the external appearance of the 510 connector plate would suggest a stronger fixing arrangement than the painfully feeble design of the latest Aegis models. Let's hope Vapey Mcgyver features one on his VMG Testing channel soon.
If you're looking for an inexpensive, easy-to-use mod for general Dimitri use, IMO it's definitely worth a closer look.
Using TCR 105, assuming resistance at 20°C= 0.2Ω, find R2 (i.e resistance at genuine 200°C)
R2 = (R1 x ∆T x TCR) + R1 R2 = (0.2 x (200-20) x 0.00105) + 0.2
R2 = 0.2378Ω
Now find non-genuine temperature T2 of same material when it undergoes equal resistance change calculated using TCR of 92
∆T = ∆R /R1(TCR)
∆T = 0.0378/(0.2 x 0.00092) ∆T = 0.0378/0.000184 = 205.435
∆T = 205.435 T2 = T1 + ∆T
∴ T2 = 20+205.435 = 225.435°C
T2 = 225.435°C