JST Connectors

UPDATE: I revised my thinking on this after realizing I was dead-wrong about xConnect connectors. See it here.

This started out as a side-note for my Pixel Data Cables story. I decided it needed it’s own write-up…

I’ve seen a lot of hate for these online, usually from people who have spent a small fortune on “xConnect”, “Ray Wu”, or “Paul Zhang” pigtails and other connectors. If you buy cheap pixels from China (which most of us do)- unless you actually buy them from a “big name” seller- they will likely have JST “SM” connectors on them.

When I first started setting up my holiday light props and strings- I was actually cutting these off to either solder pixels together directly, or to add xConnect pigtails to them. I had to ask myself “Why?!?!” Why was I wasting money buying additional pigtails? Why was I wasting my time and resources soldering the wires back together? The only real reason is they aren’t waterproof, but that is easily solved. Read on…

First- here is the humble JST “SM” connector. JST connectors like this are used inside electronics and appliances any time two sets of wires need to be connected, usually from different circuit boards or other components. They lock together securely with a small lever, and are suitable for up to 3A AC or DC circuits. With power injection- the current rating would not be exceeded in a pixel installation. (3A = 50 pixels, minimum.)

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3-pin JST Connector

I can’t even find actual current (Amp) ratings or any other specs online for the popular “Ray Wu” “Paul Zhang” or “xConnect” connectors. They have tiny connections and wire sizes so I can’t imagine they are actually any more than JST “SM” connectors. At least the JSTs are actually rated!

The pixels I buy have JSTs on both ends, and the front (data-in) side has two extra power injection leads. These are actually perfect as far as I’m concerned. Plug the data line in from the controller (Pixel Data Cables) and hook my power-injection cables to the extra wires after each (or every-other) link, and done. No proprietary Ts or extensions. Just a handful of solder-seal connectors.

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Cheap Pixel “IN” side. Note female JST connector.
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Cheap pixel “OUT” side. Note male JST connector.

The odd-ball thing I have to deal with is the Chinese (or at least the vendors I’ve used) apparently don’t use the same methodology for current carrying connectors than the rest of us do. For some reason- they put FEMALE connectors on the “IN” side, which means you need to use a MALE power connector. This is ass-backwards and potentially dangerous (with power on exposed pins), but at least so far they have been consistent with it. You should work with these with the power off anyway. 😉

I’ve only really heard two objections to JST connectors:

“Everyone uses Ray Wu or xConnect, so you should too!”

Obviously not. I’ve heard from lots of people who don’t. Some just solder (or use solder-seals), and many do use the JST connectors. There are also other alternatives like automotive “TE Superseal”-style connectors, like these, which also work great:

“TE” Connector

I use 2-pin versions of these for power injection. They can carry much higher currents, are waterproof and are very easy to work with.

What happened is pixel enthusiasts started buying pixels from Ray Wu, Paul Zhang and other larger sellers, and those sellers came up with their own interconnects- pigtails, extensions, power injection Ts, etc.- to make connecting them together easy. That’s great- it made the hobby a lot more accessible to people who don’t want to fuss with things like soldering or crimping. It also made it easier to deal with for folks coming from the “AC” lighting world, like Light-o-Rama, or those who started with completely proprietary systems like Philips and GE.

These have become the “Name Brands” of pixels, with buyers locked-in to their connector ecosystems. If you started buying xConnect- you will keep buying xConnect. Of course- the connectors can be cut off and replaced easily enough, but if you are already paying a premium to buy pixels that include them- why would you?

What bothers me about all of this is people who are just starting out are almost immediately told they “have” to buy pixels from one of these vendors and use their connectors. In some cases, I think the “advice” is coming from shell accounts created by/for the vendors, but most are just enthusiastic pixel pushers who are invested in that particular system and like it because it is all they work with, so they enthusiastically recommend it.

It’s discouraging for anyone starting out though- since these “high-end” pixels and connectors can easily add 1/3 or more to the cost of putting together a show. It’s the same for 12v vs. 5v, and Falcon vs. Kulp (vs. NodeMCU/ESPixelStick), but those are debates for another time. If you want a more plug-and-play solution and don’t mind spending the extra money- go for it! I’m just saying there is a cheap alternative that can work just as well. I’d rather have more pixels for the same money!

“But they aren’t waterproof!”

Nope, but you know what- they make this stuff called Dielectric Grease. Some old-timers (like me) call it “Bulb Grease”, because you put it on the light connectors and bulb bases exposed to the elements in your (old) car to keep water out of them.

You can use this stuff on all outdoor electrical connections, including your AC extension cord plugs to help keep water out of them and prevent corrosion. Obviously this won’t help things like power strips- which still need to be protected from the elements. In the case of JSTs- just a quick squirt/blob in the male side of the connector is all you need.

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This will waterproof almost any connector!

I like this stuff that I got at Menards. Cheap for a larger quantity, and it’s pressurized. No cap to unscrew- just push the lever. It’s great for sealing multiple cables going through a single cable gland into a controller box as-well.

I’ve heard from folks in online Christmas light/pixel forums that have run displays for years using JSTs in this manner with no issues!

Update (January 2021)- Well, one- and something that I’ve learned too- the dielectric grease is pretty stick and can get gunky/messy if you don’t keep things clean otherwise. It is grease, after all. Be sure to wipe off the outside of the connectors, and definitely wipe them off when you take your display apart for the season. You want the grease on the metal connectors, and not on everything else. if your connectors do get gunked-up, a good electronics/contact cleaner will take care of them. Obviously disconnect the power first!

Also- don’t wrap the connectors- this just tends to trap water and make them more susceptible to shorts and corrosion. It also makes them difficult to separate if you need to swap out a string or take your strip or prop apart for storage.

Another “problem”, although admittedly this is 100% my opinion:

One personal objection I have to the proprietary connectors is they are way too “fiddly” for me. They are small and use an O-ring to seal and threaded ring to hold them together. They use 3 tiny pins to carry current, and have a tiny plastic key and slot built in to insure the proper orientation. So- you have either twist them around to get the key to lock- or look at both ends to orient them correctly before you push them together. Then you have to screw on the securing ring. The threaded ring tends to fall off if you are assembling things yourself, and sometimes ends up on the wrong way. The O-rings can apparently fall off, break, or deteriorate, limiting the lifespan of the connector. (Of course- dielectric grease can fix this too!)

They are also an additional obstacle to purchasing, especially later in the year. “I need pixels with Ray Wu connectors and can’t wait a month or more to get them from China, but the US vendors are sold-out and only have xConnect.” Of course- many will be happy to sell you adapters too!


Don’t waste money on proprietary connectors, or cut off JST connectors just to splice in a different one, unless you have to because you already have a large installation that uses a particular connector. You can save a lot of money and time by just using what the pixels come with!

I don’t really have anything against US vendors and certain Chinese ones who are pushing these proprietary connectors and pixels. They are selling a system, and it does make it easier for a lot of people getting into this hobby. What bothers me is when others tell newbies that it is the only real option, and they are “wasting their time” considering anything else. I see this over and over again on pixel forums, and it is disheartening to say the least.