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Where to find the Right AML21 Switches

(Original thread started on 10-30-11 by Mark Speechley)

As a new builder who's brain hasn't gone yet, the AML21 debate is doing my head in. It was only a few months ago that the AML21 supply and price in the US was looking reasonable. Now, you lot need to get on a ship and leave town. Mouser has quoted a AML21BBA2BA at $35.23 and a 2AB at $31.10. What have you lot done to the economy of the world? I have just watched a video by Eric of his latest addition to his build and proudly sprouted that his new AML21BBA2BA switches have cost him a few bucks.


If I ordered 50 AML21BBA2BA's and 25 AML21BBA2AB's from here in Australia would anyone have any objections if I can get the cheaper, or am I ordering the wrong ones? Have I got the alphabet right or am I missing some letters and numbers?  Is it single pole I want?


(Posted by Ron Rollo on 10-30-11)

Hey Mark, don't forget to try eBay and remember, it does not have to be a 21 series AML. Also, you will need the socket part if you want to be able to use the AML LED MOD kit I sent you. I will do some looking tonight to see if I can find a AML source that would at least be under $10. It is getting hard for sure! 


If you have a choice look for AML21 switches with the solder lugs like this:

Ron 30


Compared to through hole PCB pins like this:

Ron 19

(But either type will work)


(Posted by Alan Norris on 10-30-11)

Try  They have had the AML21BBA2BA for $10.89 for 25-49 and $9.62 for 50-99. Their AML21BBA2BA are $9.70 and $8.58 for the same quantities. I have not ordered any yet but if prices are going up I will. Can anyone fill me in on exactly what the differences are and do I need to order per Marks list?


(Posted by Shane Barnes on 10-30-11)

Octopart is a good search engine to check vendor stock and pricing. Everything on eBay right now is expensive and if you do find an AML that is affordable and you can use it is only 1 or 2 in quantity.


(Posted by Ron Rollo on 10-30-11)

Here is a AML20 series for $6.95. It looks like it even has solder lugs which I prefer:


This AML21BBA2BB switch is a single pole alternate action. You can buy as many as you like, more than ten available.


And here are 3 AML20 series switches for $15:


Believe it or not, I am still short about five momentary switches. I may end up having to spend some big bucks on them myself. As you know, I could convert the alternate switch into a momentary switch but we end up loosing the clicking feel that a true momentary switch has. I am choosing to use authentic momentary where we know they belong.


(Posted by Mark Speechley on 10-31-11)

I have been checking out on line components. For all the different types of switches there seems to be sufficient quantities if you are prepared to pay between US$ 8-12 depending on order size. Maybe for the time being that will be the norm for the prices ?


As for Ron's suggestion of eBay I checked out the AML20 series for US$6.95 each. Looked a good deal as add a dollar for each for postage. When I hit BUY for purchasing 23 items the postage changed to US$190 !! I backed out of there in a hurry. Let the Buyer Beware. I do not trust eBay.  Could someone please simplify this for me and I think for Alan ( English Rebel).


Please just give me the number of the easiest and commonest purchased AML switch that our members have purchased and used. eg AML21BBA2AA. I know I keep getting the answers of, "You can use others such as AML20."


The problems are this:

1. AML21B (non-lighted) as against AML21C (1 Lamp)?

2. Is the AML21C (1 Lamp) good enough.? Is it acceptable for our boards to light the lamp. 6V, 14V or 28V?

3. Ron has sent me the AML Mod kit. Hence I need an AML with the socket part. Does that mean that only the AML21C is therefore the only option for me if you have this kit?

4. 1 pole or 2 pole ? What the hell does it mean anyway?


Hopefully this thread should sort out any confusion us new blokes have. Remember if we order 45 momentary and 23 alternate switches and get the wrong ones it could be very expensive.


(Posted by Ron Rollo on 10-31-11)

Hey Mark, I will try to help answer some of your questions.


The reason I keep saying we can use AML20 series switches is because that is actually stamped on the side of the AML switches that we purchased from Whitehawk Electronics. There is no long part number stamped on it that breaks it down further. The longer part number gives details such as gold plated terminals, lamp socket or not, single pole or double pole, latching or momentary, solder lugs or PCB mount. Some of these options are up to the user of course. I don't have the perfect part numbers that we need to be looking for. Well, I could come up with some but the issue is cost!


On the other hand, there is only one thing that you MUST have in your switch and that is the lamp plug socket. Most of them come with it because the center lamp socket part also has built into it the latching mechanism.


You can convert an alternate switch into a momentary switch if you have to, but I would get both types.


To answer your question on single pole, double pole or even 4 pole. A single pole means you have one side of the switch that has a common wire coming into it and up to two other wires that you can control current to. If you use all three terminals in a single pole switch, you could close a circuit when the switch is pushed and a circuit will also be close when the switch is open. In our case, we will only use two terminals out of the three on a single pole switch. The center common terminal and the terminal that closes the circuit when the switch is pressed on. That is a single pole switch.


A double pole switch is just like above but doubled! However, both poles are separated from each other and kept independent from one another. They both follow the same switch state of course.


An example of when we would want to use a double pole switches would be the left and right Aviation Master switches. One pole (or one side of the switch) would be used to tell the interface board that the switch state is either open or closed. Again, you would only need two lines of the three terminals to do this. The interface card uses very low voltage. On the other side of the switch, (the second pole) would be used to run the cooling fans that require 12 volt power. As you can see, we have one switch that is doing two things at one time independent of each other.


A four pole switch is the same as above but doubled yet again. You would be able to do four things at once, independent of each other but following the same switch state using different types of voltage, if need be. With all that said, the most we will ever need is two pole switches, no need for four or more!


In our case, 95% of all our AML switches can be single pole switches because we will only be running lines to our interface boards.


And before I made a large purchase of anything, I would order one of each of what you think will work. I have had to do this several times during the research and development phase which we are obviously still in. Like I said before, I am still 5 or 6 momentary switches short so I am still looking.


I hope this helps some and sorry for long explanations. Once you get a few switches in hand, grab a volt meter and check out how they work.


(Posted by Mark Speechley on 10-31-11)

Thanks Ron, love your work. eBay has just sent me an email saying I now own the 23 switches AML20 and to pay up. They have sent me a much different price difference to what was on the actual site. 23 switches plus postage came to US$171.85 Not too bad.


(Posted by Eric Tomlin on 10-31-11)

To tag onto Ron's post for you Mark and Alan...

The AML21/22 is nearly the perfect switch for our projects, even when you consider that they may cost more than $10 each. Why? Because you're hard pressed to find another square switch that is anywhere close in size and function that fulfills all the requirements and comes really close to the size needed for the correct appearance. With that said, could we have a better switch that is more affordable? I don't think so.


I have considered (at GREAT length) developing a replacement for the AML2x series switches. There is definitely a market for them but the issue is that R&D for a new switch when there's already a good working solution on the market makes little sense for a start-up guy like myself. However, rest assured that I am well aware of the switch issue and that I am continuously looking for ways to bring an alternative to you guys but understand that it is an arduous process and at this point it's just a serious investigation on my part and everything that Ive come up with so far puts it at around $10+. The requirement for me to produce a suitable substitute would be that it 1) Looks even more "the part" than what we currently have, 2) have components that are virtually available for the next 5-10 years and 3) be competitively priced.


I think that one issue is this: We founders of the LJ45 movement were very fortunate to start off our projects by paying only $2-$3 each for our square switches. That was misleading to US because a great number of us (almost all the charter members of Hangar 45) got them so cheap. Then a lot of you newer guys come along and are only finding them at $8+. I think that when you look at switches, and compare the AML21 to any other switch, you will find that it is very unreasonable to expect to pay only $2.55 like many of us established LJ guys did and $8+ is the norm. We just got VERY LUCKY back in the day and our source for them has dried up (A note to all the old guys here: Getting connected with Bob Andrus was probably the only good thing that came out of our older friend the Joker, right?). Another point- Go look at the closest comparable switch that's being provided to the sim builders right now- The FDS EM1. Now, I do not know absolutely what this switch is but I can tell you with certainty that it is extremely similar to the AML22 over all (an LED version of the 21) except it has "quad LEDs" which tells you that it is probably much more expensive to begin with than the normal AML21. FDS charges $59.95 for this switch, and before you faint from seeing the price or think that only their pro customers use these, understand that there are hobby/enthusiast customers that use these (from posts that Ive read on the Internet) and that it's an excellent quality product. Is that too much for a switch? It's a lot more than what I would be able to pay when you have nearly 70 of them in a project, but for some folks it's absolutely worth $59.95. The next alternative (that I know of) is their K2 switch at nearly $10 each. Tons of these have been used in projects and so $10 each seems to be very acceptable seeing that so many have been sold.


Where am I going with all of this? Our projects have to have a reliable source of switches at a reasonable price, but reasonable has a different meaning to different folks. Some of us have paid ungodly prices for genuine Honeywell toggles, but it's worth it to get the right look and feel. It's going to be the same for the square switches. However, I'm hopeful that in time someone here (myself, Ron, or both of us, or maybe someone reading this post) will develop an AML replacement. However, just like those of us who were fortunate enough to buy the real LJ45 TQ's, if you're building a sim and can buy all your AMLs at one time, it's best to get it out of the way. It's just a necessary expense, even more so than a real TQ. If you cant interact with your sim, then you have a museum piece.


Keep your heads and chins up guys, I'm confident that it will all work out.


PS- Ron mentioned the importance of the bulb carrier in the post above. Eric G. has demonstrated that it is not an absolute must and I would agree with Eric G. except that the bulb carrier makes it much easier to install an LED. But here's what's most important to the new guys- You must have a simple clad/attaching method for installing LEDs into AML21s. Ron and I both make these and they are super cheap. The reason for this is that bulbs don't have a polarity requirement (positive and negative) like an LED. We both can provide an isolated LED clad for inserting your LEDs into an AML21.


(Posted by Eric Williams on 10-31-11)

Now I get it! Thanks Eric. I didn't know what mod kit was mentioned by Ron earlier, now I get it. I remember seeing some in the conversion threads before. You are both making the PCB inserts for the LEDs?


Mark- these will make your installation of LED's super simple and negate any reason to get the non-illuminated ones. No need to look at my method at all unless the lamp socket ones become totally extinct. The inserts are definitely the way to go. Much easier.


Also, I'm with Eric on this, even at the slightly higher price- the AML's are well within the norm for what we can do with them. Our illuminated AML with the lens kit rivals the real thing in every way, except nowhere near the cost. And also as Eric pointed out- the cost of other similar "simulation based" switches is enough to make a person faint.


(Posted by Ron Rollo on 10-31-11)

We are using LEDs but they have to be in the 2.5 to 3 volt range. The LED AMLs in this case will not work. We need to use the incandescent version and the AML LED MOD that plugs into it.  This little thing plugs into the hole inside the AML switch. Problem solved:

Ron 37


Also, every last AML switch will have at least one LED in it. Twelve of them will require double LEDs which is a whole other conversation. Another advantage to the inserts is the ease of changing the LEDs.


You can find a tutorial of how to make a dual LED AML HERE

Ron 44


(Posted by Shane Barnes on 11-10-11)

I came across some info today that you may want to be aware of as you search for AML switches. I found a couple of switches with the following part number, AML21CBA3AC-001. Most listings do not have the 001 at the end of the part number but it is something you need to be aware of as this is a different version of the switch. 001 indicates that the switch has been modified and you will NOT hear or feel the clicking action. A tech engineer confirmed this for me, I didn't stay at a Holiday Inn last night!


Found a source for cheaper AML-21 switches on EBAY and picked up a few lots.  These are momentary switches with the solder lug terminals.  Looks like he still has 24 lots of 5 available. At 50$ for a lot, these work out to only $10 each.



Jason Hite FlightDeckSoft

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