The answer depends on the AMS generation. The original enclosed AMS does not actively dry filament, and Bambu lists no active drying function for AMS lite. AMS 2 Pro actively dries up to 65 °C; AMS HT actively dries up to 85 °C.

That does not make every external dryer redundant. The exact filament instruction, spool shape, automatic-feed restriction, drying capacity, and printer connection still decide the correct path.

The four-system answer at a glance

Bambu system Automatic material handling Active drying Highest specified drying temperature Moisture role When a separate dryer still makes sense
Original AMS Four bays No Not applicable Enclosed storage with desiccant Any time a spool is already wet or needs a controlled drying cycle
AMS lite Four open holders No active drying feature specified Not applicable Automatic feeding, not sealed conditioning When the material needs drying before or during the print workflow
AMS 2 Pro Four bays Yes 65 °C Active drying, venting, spool rotation, then sealed storage When 65 °C is insufficient, the spool or material cannot use the normal path, or independent capacity matters
AMS HT One spool Yes 85 °C Higher-temperature drying, sealed storage, and a separate bypass outlet When the exact instruction exceeds its limits, standalone capacity is needed, or the connected configuration cannot perform the required workflow

The table separates three jobs that are often blurred together:

  1. Automatic feeding moves filament and changes materials.
  2. Passive dry storage slows new moisture exposure after a spool is dry.
  3. Active drying adds controlled heat and moisture discharge to remove absorbed water.

Buying the wrong job is the expensive mistake. A feeder cannot recover a wet spool merely because it contains desiccant, while a standalone dryer cannot automate a four-colour print.

Why old answers now conflict

Bambu’s 2022 explanation of the original AMS directly answers “Is there a drier in the AMS?” with no. It describes an airtight enclosure, humidity sensing, and two desiccant positions. That was accurate for the original design and remains the right rule for that unit.

The product family later changed. Bambu’s current AMS 2 Pro specification lists active moisture discharge, rotating drying, sealed storage, and a 65 °C ceiling. The AMS HT specification lists the same functional stages with an 85 °C ceiling and a single-spool format.

So “AMS does not dry” is no longer a safe family-wide statement. Neither is “AMS replaces a dryer.” The model name has to come first.

Original AMS: storage after drying, not recovery drying

Choose the original AMS for automatic selection among four compatible spools and for protected storage after those spools are already in suitable condition. Its desiccant and enclosed path can help the environment stay dry; they do not establish an active drying cycle.

This creates a simple workflow boundary:

  • If filament arrived dry and has stayed dry, load it and use the AMS for feeding and storage.
  • If the spool has absorbed moisture, follow the filament maker’s drying instructions before returning it to the AMS.
  • If cardboard debris, a flexible material, or spool geometry conflicts with the feed path, do not force it through merely because the material itself can be printed by the machine.

The original Bambu source specifically warns about elastic TPU and cardboard-spool debris. It does not justify a universal third-party spool rule, so check the current unit guidance and the actual reel rather than relying on a brand name.

AMS lite: open automation with a separate moisture plan

The current AMS lite technical specification lists automatic material backup, RFID handling, filament restrictions, and a supported spool width of 40–68 mm with a 53–58 mm inner hub. It does not list active drying, a heater, a drying mode, or a drying temperature.

That makes AMS lite the clearest split workflow: use it for accessible four-spool automation, and use separate storage or drying equipment when the filament instructions require moisture control.

The open layout can be convenient because every reel is visible and easy to reach. It also means the loaded filament is not sitting in the type of sealed, actively managed chamber described for AMS 2 Pro or AMS HT. Users in a humid or dusty room should plan where spools go between jobs rather than assuming the feeder is the storage solution.

AMS 2 Pro: the integrated four-spool answer, within 65 °C

AMS 2 Pro is the closest replacement for an original AMS plus a separate ordinary-temperature dryer when four automatic feed slots and active drying are both recurring needs.

Bambu specifies:

  • active moisture discharge;
  • automatic spool rotation during drying;
  • sealed storage after the cycle;
  • temperature and humidity sensing;
  • a maximum drying temperature of 65 °C;
  • spool width of 50–68 mm and diameter of 197–202 mm.

That 65 °C figure is a ceiling, not a recommendation for every material. Use the exact filament maker’s temperature, duration, and spool-safety instructions. Bambu’s own filament guide varies the drying route by material, which is why a single “AMS setting” is not responsible advice.

The other important distinction is between drying compatibility and automatic-feed compatibility. Bambu publishes those as separate lists. A material may be eligible for a drying cycle but still be excluded from the normal printing path because it is too soft, brittle, abrasive, damp, or filled for that route.

For the narrower exact-product decision, see the AMS 2 Pro drying, feeding, and upgrade-cost review . Verify the required buffer or hub, cables, power adapter, and firmware for the exact printer before ordering.

AMS HT: higher temperature, one spool, different routing

AMS HT moves the decision in the other direction. It gives up four-bay capacity for one-spool drying up to 85 °C and a dedicated bypass outlet.

That can be the better Bambu-native role when a higher-temperature material is the recurring problem or when a soft or brittle filament needs the separate outlet. But the bypass is not the same as automatic feed and return. Bambu’s current FAQ says TPU routed through that outlet is manually advanced and that the unit cannot actively dry while feeding through the bypass.

AMS HT also is not a free-standing dryer in the ordinary sense. The retained product guidance says it must connect to a powered printer by the bus cable to use its drying function. Treat printer support, accessory requirements, and print-while-drying behavior as current configuration checks, not permanent facts copied from an old article.

The decision map

Use this order rather than starting with a product name.

1. Identify the actual moisture job

If the spool is printing cleanly and simply needs protected storage, original AMS or the sealed storage stage of a newer unit may be enough. If the spool is already wet, require an active drying route supported by the filament maker.

2. Match the required temperature

Compare the filament instruction with the system ceiling. A requirement that fits below 65 °C may fit AMS 2 Pro. A higher requirement may fit AMS HT up to 85 °C. Anything outside the stated system or spool limit needs a different approved method.

3. Check drying and feeding separately

Do not infer that “can dry” means “can automatically feed.” Read both manufacturer lists. This matters most for soft, brittle, abrasive, damp, and fibre-filled materials.

4. Decide whether capacity or integration matters more

AMS 2 Pro conditions four loaded spools inside the automatic system. AMS HT focuses on one spool at a higher ceiling. A separate dryer can remain useful when another spool must be conditioned independently or when the automatic system is occupied.

5. Price the complete installed path

The product body is not always the whole configuration. Confirm the printer, firmware, buffer or hub, cables, power adapter, PTFE routing, and clearance from current Bambu documentation. Do not turn a changing compatibility requirement into a permanent promise.

Verified buying routes

Use Bambu’s current pages to confirm the exact unit and required accessories. Amazon availability can change, so the affiliate routes below are deliberately labelled searches rather than disguised direct product pages.

Those Amazon links use the configured 3dprint01c-20 tag and intentionally do not claim a specific seller, package, stock state, or ASIN.

Methodology and limits

This current-change map was checked on 29 August 2026 against five first-party Bambu sources: the original AMS engineering explanation, current AMS lite specifications, current AMS 2 Pro specifications, current AMS HT specifications and FAQ, and Bambu’s filament guide.

We normalized each source into five fields: automatic-feed capacity, passive storage, active drying, maximum stated drying temperature, and spool/material-path constraints. We then derived the workflow rules above. The retained dataset is a source-level reconciliation, not a hands-on test.

We did not dry, weigh, print, or measure any filament. We did not establish achieved spool-core temperature, drying speed, power use, print-quality improvement, humidity reduction, durability, or owner consensus. Firmware and accessory requirements can change; the current manufacturer page controls. The exact filament maker’s drying and spool-safety instructions always outrank a generalized temperature table.

Bottom line

The original AMS stores and feeds; it does not actively dry. AMS lite feeds four open spools and needs a separate moisture plan. AMS 2 Pro combines four-spool automation with drying up to 65 °C. AMS HT raises the drying ceiling to 85 °C for one spool and adds a bypass path with different limits.

Keep a separate dryer when the chosen AMS is passive, the material instruction falls outside its temperature or feed path, another spool needs independent capacity, or the exact printer configuration cannot perform the required drying workflow. The right answer is a model-and-material match, not a family-wide yes or no.