AMS & Color
Which AMS to use with a P1S
The P1S takes the sealed four-spool units, which means you get a real choice - and one of the two options is clearly better.
By Michael W. · Published October 5, 2026
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Which AMS fits a P1S
The sealed four-spool units: the AMS and the AMS 2 Pro. Buy the 2 Pro — it adds active filament drying, which is the single most useful thing the newer unit does.
The AMS Lite does not fit a P1S. It is the A-series unit. This is the most common wrong purchase in the category.
For nylon or polycarbonate, add an AMS HT or a high-temperature dryer — standard active drying does not reach what those materials need.
What changes once it is fitted
Your prints get slower and use more filament. Not because of the unit but because of what you will do with it. Multi-color prints purge at every change, and the purge tower is real. This is the trade and it is worth knowing before the first print rather than after.
Your filament profiles start mattering more. With four spools loaded, mismatching one is easy and the result is a ruined print. RFID logging on the sealed units is specifically there to prevent that, and it is worth using rather than overriding.
Your PETG stops stringing, if you bought the 2 Pro. This is the under-sold benefit. People buy it for color and keep it for drying.
Plan the space first
The unit sits on top of the P1S, which means you need vertical clearance above the printer that you may not have if it lives on a shelf. Measure before ordering. People discover this after delivery more often than you would expect, and the fix is usually moving the printer rather than the unit.
The three mistakes that cost a print
Loading a snapped filament end
Dry brittle filament snaps, and a short piece left inside the path blocks the next load. Check the end before loading and cut it cleanly at an angle. This is the single most common AMS failure — feeding diagnosis.
Running TPU through it
Soft filament buckles in a long guided path. Most P1S owners feed TPU directly into the extruder instead. What works with TPU.
Leaving spools loaded for months
A sealed unit is good storage, not perfect storage, and the 2 Pro's drying runs when you ask it to. If a spool has sat loaded and unused for a long time, dry it before a critical print rather than assuming the enclosure handled it.
Where to go next
The AMS roundup covers the accessories worth having alongside the unit. The AMS 2 Pro page has the full case for it. And if you are not sure multi-color is worth it at all, the manual method is a free way to find out.
What to buy
Stock photograph of this product class, not of this specific unit.
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1. The one to buy
Bambu Lab AMS 2 Pro
Active drying is the difference, and on a P1S it is the difference that matters.
For a P1S this is the straightforward answer. Four colors plus active drying, sealed, with humidity monitoring and RFID logging. It is also the purchase that most often removes the urge to replace the printer entirely.
The P1S is enclosed, which means the unit sits on top and feeds in through the existing path — this is the configuration the sealed AMS was designed around.
What it gets right
- Active drying means the spool you print from is the spool you dried — no transfer step, no re-absorption window
- Four colors on a machine you already own, for a fraction of a new printer
- RFID logging removes the single most common cause of a ruined multi-color print: the wrong material profile
What it does not
- Four-color printing wastes filament on every tool change; the purge tower is real and it is not small
- If you only print single-color PLA, you are buying a dryer with a filament changer attached
- Needs the space beside or above the printer that your shelf may not have
| Type | Four-spool automatic material system |
|---|---|
| Headline feature | Active filament drying |
| Inherits | Humidity monitoring and RFID logging from the original AMS |
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2. Only if the price gap is large
Bambu Lab AMS
Same four spools, sealed, with monitoring instead of drying - and chainable for more materials.
The original sealed four-spool unit. On a P1S it fits and works, and the sealed enclosure alone keeps spools far drier than open air.
Its one unique capability is chaining for more than four materials. If you genuinely need six or eight colors, that matters. Otherwise the 2 Pro's drying is worth more than the saving.
What it gets right
- The cheapest route to four-color printing on an enclosed Bambu machine
- Sealed enclosure with humidity monitoring keeps loaded spools far drier than open air
- Multiple units can be chained for more than four materials
What it does not
- Monitors humidity; it does not do anything about it. That is what the 2 Pro added
- No active drying means a wet spool loaded here stays wet
- Not compatible with the A1 series, which uses AMS Lite instead
| Type | Four-spool filament storage and switching system |
|---|---|
| Features | Humidity monitoring and RFID logging |
| Drying | None — storage and monitoring only |
Questions people actually ask
Which AMS works with a P1S?
The sealed four-spool units - the AMS and the AMS 2 Pro. Buy the 2 Pro, because it adds active filament drying. The AMS Lite does not fit a P1S; it is the unit for the A1 and A1 mini.
Do I need an AMS 2 Pro or will the original AMS do?
The original works on a P1S and its sealed enclosure keeps spools much drier than open air. The 2 Pro actively dries rather than only monitoring humidity, which matters for PETG, TPU and anything filled. The one thing the original does uniquely is chain for more than four materials.
Where does the AMS sit on a P1S?
On top of the printer, feeding in through the existing filament path. That means you need vertical clearance above the machine, which is worth measuring before you order - a printer on a shelf often does not have it.
Will an AMS slow my prints down?
Multi-color prints are slower and use more filament, because every color change purges the nozzle. That is the trade rather than a fault. Single-color prints from an AMS run at normal speed.
Can I run TPU through an AMS on a P1S?
Not reliably. Soft filament buckles in a long guided path, and the usual symptom is a failed load rather than a bad print. Most owners feed TPU directly into the extruder instead, which works fine.
Sources
Read this next
- Bambu Lab AMS 2 ProWhy active drying makes the AMS 2 Pro a different product from the original AMS, and the case for buying it instead of a new printer.
- The best Bambu Lab AMS accessoriesWhich AMS to buy for your printer, plus the accessories that fix feeding problems and desk space - ranked by the problem each solves.
- AMS not loading filamentThe four real causes of an AMS feed failure in diagnostic order, three of which cost nothing and take minutes.
- Running TPU through an AMSWhy TPU buckles in an AMS path, what genuinely helps, and why direct feeding is the answer most Bambu owners arrive at.
- Upgrading from a P1SThe two reasons to replace a P1S and the four cheaper parts that cover everything else, with the arithmetic laid out.
- Bambu Lab P1SWhat the P1S already does well, the three things it genuinely cannot do, and which cheap part fixes each complaint instead of a new machine.