# SX Mini mods, the YiHi classes and the role of their chips > SX Mini mod range decoded from YiHi's own pages. What the chip really does, and how to tell the G, SL, MQ and X classes apart before you choose. With most high-end mods, the metal, the finish and the engraving get looked at first. An **SX Mini mod** turns that order round, because its maker, YiHi, is first and foremost a chip designer. The catch is a range that strings together letters, G, SL, MQ, X or T, and chip references such as SX550J or SX750, which retailer listings quote without always explaining. Where does the reputation of these chips come from, and what do they actually do inside the mod? ## SX Mini mods, the work of a chip designer An **SX Mini mod** is a regulated box mod from SXmini, the brand of YiHi, a company founded in 2010 in Dongguan that specialises in developing vape chips and high-end devices. Every model carries an in-house chip, named SX followed by a number, and the range is split into classes identified by letters. That changes the way you buy. You pick a chip and its features first, then a single or dual battery format, and only then a finish. The classes are not a straight ladder from entry level to flagship, they answer different ways of vaping. ## Where the SX chips earned their name YiHi tells this story on its official site, and it begins with chips sold to other brands. Three stages explain why the SX name carries weight with experienced vapers. ### Chips supplied to other makers YiHi dates its first original chip, the SX130, to 2013. The SX200 went into Sigelei's Legend series, the SX220 powered the iPV2 and iPV2S, and the SX300 was picked up by several manufacturers, among them Dovpo, KSD and Yosen. The SX330 then found a place in flagship models from Sigelei and Pioneer4You. ### Chips that improve through software In 2014 the SX350 launched at 30 W. Firmware updates took it step by step to 35, 40, 50 and finally 60 W on the same hardware. In October 2015, alongside the ML Class, YiHi introduced its SXi-Q software, which lets you set five profiles, C1 to C5, on a computer before sending them to the mod. ### The SXi-EQ flavour curve In May 2016 the Q Class brought in SXi-EQ, a power curve drawn by the user. The software offers five curves, S1 to S5, each with 20 adjustable points across a 10 second heating cycle. That works out at one point every half second, the same interval quoted in the G Class V2 and SL Class V2 guides. There are presets too. Soft ramps the output from 75 to 100% of the set value, while Strong starts at 125% before settling back to 100%. ## What a chip does in a high-end mod, according to YiHi A regulated mod does more than connect a battery to a coil. Its chip measures, calculates and shapes the power it delivers, and YiHi's pages describe those three jobs across several models. ### Reading resistance to a ten-thousandth of an ohm The G Class V2 reads resistance to 0.0001 ohm, as the Q Class did before it with what YiHi describes as 16-bit sampling. That precision serves temperature control, where the chip estimates the temperature of the wire from the change in its resistance. The calculation only works with wires whose coefficient is known. The G Class V2 accepts SS316L stainless steel, Ni200 nickel, titanium and a custom coefficient, the TCR. ### Capping the temperature or following a curve YiHi contrasts two approaches. So-called constant control, the approach of the Evolv DNA chips found in [Lost Vape's Thelema DNA models](/uk/lost-vape-thelema-range/), sets a ceiling the wire never goes past. SXmini's dynamic heating curve keeps adjusting the heat within a set range, according to how hard you draw, how long the coil fires and how well e-liquid is reaching it. The SL Class V2 offers both styles, and the G Class V2 also advertises two temperature modulation modes. The constant style aims for precision, while the dynamic one accepts slight fluctuations, which YiHi presents as a way to limit burnt hits when the e-liquid runs short. ### Holding the output from a full battery to a flat one On the MQ Class and the MX Class, YiHi highlights a buck-boost circuit, able to step voltage down or up. It adapts the battery's voltage, which falls as the cell drains, so as to aim for the same output from a full battery to a nearly flat one. The G Class V2 adds a chip protected by a waterproof coating, a dual processor design and a standby current below 20 microamps. These are electronic choices you will not see on a shop listing. ## The SX Mini mod classes in one table YiHi's official catalogue holds nineteen listings across its two mod categories, special editions included. The table keeps one line per class, with the chip references as the product pages give them. | Class | Batteries | Output | Chip | |---|---|---|---| | G Class V2 | Two 18650 | 10 to 200 W | SX750 | | G Class | Two 18650 | 10 to 200 W | SX550J | | T Class | Two 18650 | 1 to 200 W | SX580J | | X Class, auto squonk | Two 18650 | 5 to 200 W | SX650J | | Q Class | Two 18650 | Up to 200 W | SX450J | | SL Class V2 | One 18650, 20700 or 21700 | 5 to 100 W | SX730 | | SL Class | One 18650, 20700 or 21700 | Up to 100 W | SX485J | | MQ Plus | One 21700, 20700 or 18650 | 5 to 100 W | SX418J | | MQ Class | One 18650 | 1 to 60 W | SX416J | | MX Class | One 18650 | 5 to 75 W | SX480J-BT | | ML Class | One 18650 | 75 W, 85 W in bypass | SX350J-V2 | One naming quirk is worth flagging. The G Class V2 product page lists an SX750 chip and its user guide an SX750J, and the same gap appears between the SL Class V2 product page (SX730) and its guide (SX730J). In each case it is the same model, described by two official pages. Two families emerge. The dual 18650 mods reach 200 W, the single battery ones top out between 60 and 100 W, and several take 20700 and 21700 cells. On finish, the SL Class comes in 316 stainless steel with carbon fibre, stabilised wood or etched aluminium, and the G Class exists in a 24 carat gold plated version, the Luxury Golden, with its own SX550J-L chip. ## Which SX Mini mod for which kind of vaper The table boils down to a few profiles. No single model ticks every box, and the right choice depends first on the number of batteries and the kind of tuning you want. - For fine tuning and updates without a computer, the G Class V2, with its WiFi and five memory profiles. - For a single battery and both temperature control styles, the SL Class V2, which weighs 136 g. - For straightforward power adjustment, the MQ Class on an 18650, or the MQ Plus, which reaches 100 W and takes atomisers up to 28 mm. - For squonking, the X Class, which YiHi equips with an automatic squonk function. - For the object as much as the chip, the SL Class editions in stabilised wood or carbon fibre. Whichever class you settle on, refillable tanks sold in the UK are capped at 2 ml. YiHi's own Hakutaku atomiser shows how this plays out, with a 4.2 ml standard version and a 2 ml European version. ## FAQ Five practical points drawn from YiHi's official guides, beyond choosing a class. ### What is YiHi's Pure mode? YiHi presents it as a technology that detects the coil's resistance and sets the output by itself, refusing to fire a dry coil. The G Class product page says it works with all atomisers. ### Why lock the resistance at room temperature in temperature control? YiHi's guides ask for it before every use. The chip compares the measured resistance with a reference value, and a reference taken on a wire that is already warm skews the temperature estimate. ### How do you switch on and lock an SX Mini? On the G Class V2 and the SL Class V2, five presses of the fire button switch the mod on and three presses lock or unlock it. On the SL Class V2, switching off goes through the System Off line of the main menu. ### Can a G Class V2 be updated without a computer? Yes. Over its WiFi connection it downloads firmware, themes, wallpapers and language packs, partly through YiHi's SX-Panel service. The guide walks through pairing with a phone and two QR codes. ### What are the M1 to M5 profiles for? They store the settings for several atomisers so you can switch between them without starting from scratch. Their names can be changed from SX-Panel. ## SX Mini mod, choose the chip before the shell YiHi's mods owe their reputation to a history of chips, supplied to other brands and then extended through software, and to features the maker documents in detail, SXi-EQ curves, constant or dynamic temperature control and WiFi updates. To choose an **SX Mini mod**, the sound approach is to start from the chip and the number of batteries, and only then look at the finish. It is a method that holds for any high-end kit, where the electronics count as much as what you hold in your hand. ## In the same vein - [Aegis Legend 5, what the mod owes to the Legend line](/uk/geekvape-aegis-legend-5/) - [Vandy Vape, a catalogue built for advanced vapers](/uk/vandy-vape-brand/) - [Centaurus M200, the object and its manual in detail](/uk/centaurus-m200/) Sillage Doré is written for adult readers only. Vaping products usually contain nicotine, which is addictive, and vaping products are not for sale to under-18s in the UK. We describe equipment here, and nothing on this page is a buying recommendation.