Cherry MX Low Profile - Review / Specs / Compability

[Pizza_on_Pineapple]

Hi geekhack, today I'd like to share my thoughts on Cherry's Low Profile switches:

Cherry's MX Low Profile RGB switches (MXLP) got announced at CES 2018 but information about them is still fairly sparse. I ordered a few and will share my thoughts, tests and measurements here.
MXLP switches seem to be generally only available in prebuilt keyboards by major manufacturers like Corsair or Cooler Master. The only place I found where you can buy just the switches was the German hardware shop Reichelt.

The switches come in two variants (both linear):
• Cherry MX Low Profile Red RGB (CHERRY MX1B-L2NA)
• Cherry MX Low Profile Silver RGB (CHERRY MX1B-52NA)
With the difference being that the silver switch actuates at 1.0mm instead of 1.2mm. Otherwise they appear to be the same (apart from the colour).




Specs
here is the technical data for the red (silver) switch listed in the official Cherry spec sheet:
• Protection class: IP40
• Operation characteristics: Low Profile, linear
• Switching voltage: 12V AC/DC max.
• Dielectric strength: 500V / 50Hz
• Durability: > 50 million actuations
• Contact configuration: Single-pole contact
• Actuator travel: 3.2 ±0.25mm
• Pretravel: 1.2± 0.3mm (1.0± 0.3mm)
• Initial force: 40cN min. (30 cN min.)
• Actuation force: 45± 15cN
• Bounce time: typically 1 ms
• Minimum lead spacing: 16 mm
• Lighting: SMD LED, mounted directly on the circuit board
• Insulation materials: Thermoplastics
• Spring: Stainless steel
• Contacts: High-quality gold alloy
• Storage Temperature: -40°C to 70°C
• Operating Temperature: 5°C to 40°C
• Humidity: Storage: average <50% max. 3 months / 75% max. 15 days, operation: 5% to 95% without condensation

The deskthority wiki page has some more information here: https://deskthority.net/wiki/Cherry_MX_Low_Profile


Measurements
There is no public datasheet available but Nomad099 got his hands on one which you can check out for more accurate measurements than mine https://geekhack.org/index.php?topic=106825
General
Much like a normal MX switch it's built of 6 pieces: top housing, bottom housing, stem, leaf pins and a spring.

More

The stem is even with the top housings edge around the stem hole when fully pressed in (3.2mm travel).

Footprint
The switches footprint is very unique and therefore not compatible with most PCBs. The switch is only available in a 3 pin design but due to the large cross shaped hole that is needed in the PCB I doubt that the switch will wiggle much.


I designed a footprint based on my measurements and uploaded everything here: https://github.com/floookay/crkbd-mxlp
The PCB is fully tested and everything works great so far

More

Top Housing
The top housing is made out of a clear material and is klipped similiarly to Kailh's switches onto the bottom housing. The top housing also has this little pin right over the posibble LED spot of the PCB. This pin is split to the left and right which could direct the light of the LED around the top housing for a more even glow, maybe. Cool detail nonetheless. You can open the switch pretty easily by hand. Just raise the lugs on each side with your fingernail and jam your nail near the pin in the front to unclip that as well.

More

Bottom Housing
The bottom housing has a milky finish, similiar to Cherry's other RGB switches. There is also some sort of grease in the stem area applied. The bottom housing has quite the unique footprint as you can see in the pictures.

More

Stem
The stem is X mm long and also has this grease preapplied. The cross stem is surrounded by a cylinder to protect the switches inside from dust.

More

Spring
The spring is slightly smaller than a normal MX spring as you can see in the picture.

More

I measured a length of 12.88mm and a diameter of 2.82mm.

Leaf / Pins
Pin positions are similiar to Kailh Chocs but flipped. The contact pin is however slightly more inward and lower.


Thoughts
Technically the MXLP switches have a lower profile than MX switches but if you care about the lowest profile possible there is probably no way around ditching the MX stem and going for something smaller like Kailh's Choc (V1) switches.
Comparison of Choc V1 & MXLP:

Comparison of MX & MXLP:

Plate comparison of Choc, MX, MXLP:

You should only use a plate with MXLP switches if your keycaps are low profile as well, see below.


Feel
The switches feel alright so far. They do have a somewhat heavy bottom out in comparison to normal MX Reds.
They are also just as scratchy as normal MX Reds. The stem, leaf & bottom housing also seem to have some sort of grease pre-applied as you can see in this picture.
Lubing these switches is fairly pointless: Opening them is quite the hassle and the difference in feel after lubing the stem and the bottom housing with 205g0 is barely noticeable.
I'll add more impressions of the switch to this section once I built my Corne.


Kailh Chocs V2
Kailh recently released a successor to their low profile Choc switches, the Choc V2. Much like Cherry's MXLP switch it has a MX stem for compability with (technically) a wide range of keycaps. I wasn't able get my hands on these as of yet and therefore cannot make a comparison.


TTC Low Profile switch
As mentioned by Findecanor, TTC is also working on a new switch similiar to this one.
Here are a few comparison shots between MXLP and TTC's new switch: https://twitter.com/Xe_ry/status/1304729305411284993


Compability with keycaps
All MX style keycaps that are not low profile will collide with a plate if you use one because the stem moves past the point where you snap the switch into the plate as you can see in these two pictures:


Cherry PBT dye-sub
R1 keys are working fine but R2-R4 are all colliding with the switch.

More

R4: R1:

More

GMK
Not compatible. You can barely put the caps onto the stem because they collide almost immediately with the switch housing. Especially R3 barely holds onto the switch. Sanding off the plate supports from the switch doesn't resolve that either.

More

PBT MT3
Because the switch snugs inside the keycap and MT3 caps are very thick, all caps are brushing on the switches. Heightwise they shouldn't have an issue.
Sanding off the little plate supports of the switch makes them compatible! See last pic.

More

ABS MT3
These are compatible. No modifications needed. The switch snuggs nicely inside the keycap.

More

SP SA
I don't think they're colliding with the switches. I does look pretty close though. All rows sound the same as well. The switch snugs between the outer walls of the keycap.

More

DSA
no collision of the keycap with the switch.

More

XDA
no collision as well

More

KAT
- tbd


Roadmap
- test more keycap profiles
- create 3d printable inserts (to raise the keycap slightly, could make some keycaps compatible)

TL;DR
- only works properly with plateless designs if you want to use standard (non-low-profile) keycaps
- works best with DSA & XDA
- not compatible with MX/Choc/Alps PCBs. MXLP have a different footprint with a large cross-shaped cutout for the stem.



Thanks for reading, please let me know your thoughts, questions or requests what I could add. Cheers.

And thank you Findecanor for the detailed insight!

[ThereminGoat]

This is a solid looking review mate

Keep it up, I wouldn't mind seeing some more content like this!

[Findecanor]

The switches footprint is very unique and therefore not compatible with most PCBs. The switch is only available in a 3 pin design but due to the large cross shaped hole that is needed in the PCB I doubt that the switch will wiggle much.
[...]
Kailh recently released a successor to their low profile Choc switches, the Choc V2. Much like Cherry's MXLP switch it has a MX stem for compability with (technically) a wide range of keycaps. I wasn't able get my hands on these as of yet and therefore cannot make a comparison.
[...]
- create KiCAD footprint

The MXLP's official footprint actually has a circular hole in the middle large enough to fit three arms of the cross, except the longest arm that gets another hole.
TTC is making a MXLP-clone that will fit this footprint, but not a cross-shaped footprint. There is more info about this switch in the thread about the Pitta keyboard which will have this.

Keebio had been in touch Cherry early, and posted a Kicad footprint in their Github repository before much else was known about the switch.

However, I think the best for any new low-profile keyboard would be to use a combined footprint that would fit several of these switches. For the TTC thread I whipped up a drawing in QCad just to see if it could be done, and it can!
It also includes the Kailh Choc (V1) but you would have to choose between supporting clicky Choc and clicky Choc V2. And Choc V2 does not have fixing pins so those would need to be plate-mounted.

ps. Please excuse me for not seeing this thread earlier.

[Pizza_on_Pineapple]

This is a solid looking review mate

Keep it up, I wouldn't mind seeing some more content like this!

Thanks ThereminGoat! I love your reviews 

The switches footprint is very unique and therefore not compatible with most PCBs. The switch is only available in a 3 pin design but due to the large cross shaped hole that is needed in the PCB I doubt that the switch will wiggle much.
[...]
Kailh recently released a successor to their low profile Choc switches, the Choc V2. Much like Cherry's MXLP switch it has a MX stem for compability with (technically) a wide range of keycaps. I wasn't able get my hands on these as of yet and therefore cannot make a comparison.
[...]
- create KiCAD footprint

The MXLP's official footprint actually has a circular hole in the middle large enough to fit three arms of the cross, except the longest arm that gets another hole.
TTC is making a MXLP-clone that will fit this footprint, but not a cross-shaped footprint. There is more info about this switch in the thread about the Pitta keyboard which will have this.

Keebio had been in touch Cherry early, and posted a Kicad footprint in their Github repository before much else was known about the switch.

However, I think the best for any new low-profile keyboard would be to use a combined footprint that would fit both Cherry's, TTC's and Kailh's Choc V2 and Choc. Back in June I whipped up a drawing in QCad just to see if it could be done, and it can!
However, you would have to choose between supporting clicky Choc (V1) and clicky Choc V2. And Choc V2 does not have fixing pins so those would need to be plate-mounted.

ps. Please excuse me for not seeing this thread earlier.

Oh thank you! Can't believe I missed the footprint in keebio's repo. Thanks for the insight, seems like I overlooked a lot of already existing data. I also didn't know about TTC's switch. I'll add some information to this page and maybe later on some of my findings to the deskthority wiki.
In the meantime I designed a cross shaped footprint that fits the switch quite snugly. I was planning on releasing the files once I tested that I didn't mess up the Corne's RGB LED matrix.

I totally agree with you that an universal footprint would be the best way to go.

[suicidal_orange]

Nice write up, I was wondering about these

[Pizza_on_Pineapple]

Nice write up, I was wondering about these

Thank you!

[Coreda]

Nice. Haven't come across a comparison and keycap testing post for these all together like this before. Will be useful for future reference