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For most people choosing between the Bambu Lab AMS vs AMS 2 Pro vs AMS HT, the answer is the AMS 2 Pro: four spools with active drying. Add an AMS HT only if you print materials that need more heat than the 2 Pro can deliver. The original AMS only makes sense if you find it discounted and you print PLA and PETG. Each unit is a feeder, a sealed storage box, and in two cases a dryer. For functional parts, the dryer matters more than the color count.
What is the actual difference between AMS, AMS 2 Pro, and AMS HT?
The original AMS is the older four-spool unit. It still works where supported, but it does not actively dry filament. It relies on desiccant, and it has a humidity sensor that reports to the printer screen, Bambu Studio and Bambu Handy. That gives you passive storage. It does not remove moisture from a spool that is already wet.
The AMS 2 Pro keeps four spools and adds a heater. It combines four-spool feeding with active drying up to 65°C. Bambu also lists a brushless servo feed motor that it says speeds up filament feeding by 60% and ceramic filament inlets for wear resistance. Easier tube access helps when filament snaps inside the unit.
The AMS HT is a different kind of product. It is a one-spool feeder and dryer that goes up to 85°C. It is also much smaller. It weighs 1.21 kg and measures 114 × 280 × 225 mm, against 372 × 280 × 226 mm and 2.5 kg for the AMS 2 Pro. It adds a bypass outlet, covered below.
| AMS | AMS 2 Pro | AMS HT | |
|---|---|---|---|
| Spools | 4 | 4 | 1 |
| Active drying | None | 65°C max | 85°C max |
| List price | $249 | $299 | $139 |
| Price per spool slot | $62.25 | $74.75 | $139 |
The per-slot figures are my own arithmetic from Bambu’s list prices. During Bambu’s Black Friday sale, the AMS was $199 and the AMS HT was $119, and Bambu’s AMS bundle page showed the AMS 2 Pro at $229. Sale prices change, so check the store before you buy.
Is 65°C enough? Matching the dryer to your filament
The data sheets for your filament decide this, not the marketing. Bambu’s own position is that materials marked with an asterisk need a higher drying temperature, and it recommends the AMS HT for them. One breakdown of those materials lists ABS, ASA, PC, PA and PVA as needing more than the 2 Pro can reach. The 2 Pro’s own limit also has a condition. It only hits 65°C when the room is above 25°C. Below that, heat loss can keep it short of the maximum. A cold workshop in winter will not get you a full 65°C cycle.
Here is how that maps to materials. PLA and PETG are fine at 65°C or below. For nylon, polycarbonate, ABS, and ASA, the 85°C unit is the one built for them. Even the HT may not fully dry PVA, PPS-CF or PPA-CF. Those need an oven or a dedicated dryer. See the filament drying comparison for that.
There is a PLA trap as well. PLA starts to soften around 55–60°C, so don’t improvise higher temperatures. The AMS also lowers the setpoint when a neighboring spool is in use. It drops to 45°C when drying PETG while printing PLA, and to 55°C when drying ABS while printing PETG. That protects the spool in the feed path. It also means a drying cycle during a print is slower than one done idle.
Can you dry and print at the same time?
Partly. The supported case is that the printer prints from some AMS units or an external spool holder, while the units not involved in the job dry. A unit that is feeding the current job can’t dry, and that includes one set up for auto-refill. Plan around this. A common layout is one 2 Pro feeding the job and a second unit drying the next spool.
Power adds another constraint. The AMS HT uses its included mains power cord, because the printer’s bus connection does not power drying. The AMS 2 Pro depends on the printer. P1 and X1 owners should budget for a drying power adapter. Drying several 2 Pro units at once also needs a separately purchased power adapter.
What does the AMS HT bypass outlet do?
Abrasive and flexible filaments are hard on a roller-based feed path. The HT has a bypass outlet for TPE, generic TPU, Bambu PET-CF and TPU 95A, and other carbon- or glass-fiber filament. The AMS 2 Pro’s unsupported list includes TPE, generic TPU, Bambu PET-CF/TPU 95A, and other filament that contains carbon or glass fiber. Bambu’s own PLA-CF, PETG-CF and PAHT-CF are listed as supported on both units.
There is a catch. With TPU, the HT cannot use automatic feed and return, but it can serve as a drying box. It also can’t dry while a print is being fed through the bypass port. So the bypass is a dry, clean path for one spool, not automation. For TPU gaskets or bumpers you manually load that spool, and it stays isolated from the AMS rollers.
Which AMS setup makes sense for functional parts?
Be honest about what you need multi-material for. Brackets, jigs, and enclosures are mostly single-material parts. Color changes are cosmetic, and purge waste is set by having a single nozzle, not by the unit feeding it. The real jobs are dry storage, automatic spool swaps, and occasional support interfaces. Soluble or PLA-on-PETG supports are the typical case.
These are the setups I’d reach for, based on the specs:
PLA and PETG, with some ABS or ASA. Get one AMS 2 Pro. It dries the common materials, and the sealed storage keeps opened spools in better shape. If you’re picking a printer at the same time, the P1S vs P2S combo breakdown covers the bundle. For PETG choices, the PETG brand comparison lists TDS numbers.
Nylon, PC, or PA-CF as a regular material. Add an AMS HT, and consider it before a second 2 Pro. These materials absorb moisture quickly, and wet nylon prints poorly and loses toughness. A dryer that can reach their data-sheet temperature is the better investment. At $139 list, it costs less than half of a 2 Pro.
Mixed workflow. Combine them. H2-series printers take up to four AMS or AMS 2 Pro units plus eight AMS HT, for 24 filaments in total. On P1 and X1 printers, the limit is four units in any mix, for 16 colors. A 2 Pro for daily PLA/PETG plus an HT for the engineering spool is a sensible mix on a P1S. The H2D/H2S/X2D lineup post covers what the larger machines add.
Original AMS. The original AMS is the budget pick if you can get it at or near $199 and print only PLA and PETG. Desiccant in a sealed box does keep dry filament dry. It can’t recover a damp spool, and it won’t take TPU or carbon fiber. The cost difference to the 2 Pro is small compared with the printer, so I wouldn’t choose it for a new engineering setup.
What the specs don’t tell you
A spec sheet can’t say how reliable the feeders are over months. Community reports on the 2 Pro are positive about PETG drying and easier work when a filament breaks inside, but those are user posts, not measurements. Treat them as anecdotes.
Drying a spool to the right temperature does not fix a bad print profile. Moisture is one variable. Nozzle temperature, cooling, and layer adhesion in Z still decide whether a bracket holds. A heated storage unit gets the filament into condition. It doesn’t print the part for you. Check the TDS for the material you actually use, and remember printed parts land below the sheet values, especially across layers.