Jump to content

ar2ax wiring/polarity matchup


mantis

Recommended Posts

I'm having a difficult time figuring out the proper wiring for a 2ax, the classic crossover diagrams don't indicate + - and the drivers themselves don't indicate the + - and the wires are of different color some of the time. Its just a mess of confusion with few points of reference and its difficult to communicate and infer from posts.

Here is a quick diagram I put together, I have made it as simple as possible (I hope). The image is looking straight at the speaker from the front as though all drivers were installed. The red boxes indicate whats inside the speaker cabinet as if you could see right through the speaker, so those are directly as installed as looking from the front (no reversing or flipping or any of that). Now that we have a consistent reference for communicating the connection points, lets please match them up to the crossover diagram. All we have to do is match A/B with 1/2:

ar2axwiring.png

So for the Woofer, Midrange, and Tweeter what is the proper matchup?

eg:Woofer: A goes to 2, B goes to 1

Thank you.

Link to comment
Share on other sites

I think this covers it...

The 2ax is confusing, as it often has the same color wire attached to the #1 and #2 pot terminals.

Roy

Actually, could I ask for you to review this complete diagram just to be sure? I'm not sure if I was misreading your labeling before but I just want to make sure the thing is complete:

ar2axcheck.png

Link to comment
Share on other sites

Actually, could I ask for you to review this complete diagram just to be sure?

The diagram is incorrect. I've drawn over it using the wire colors to make it easier to discuss.

I also went back and changed the pot terminal labeling in my first response which was not correct relative to your wiring diagram. The #1 pot terminal, however, should be on the right when looking at it from the perspective you have drawn, which is what confused me. It is correctly depicted in the drawing below.

Let me know if the revisions make sense to you. Sorry for the mess of colored lines, but it was the most expedient way to correct your drawing. I've also attached a photo of a 2ax crossover a forum member sent awhile back. The caps are the only changes that were made to it. (The cabinet terminals are labeled in white, and the pots in red.)

The third photo is to clarify my comments about the pot terminals.

Roy

post-101150-1290052950.png post-101150-1290052958.jpg post-101150-1290054523.jpg

Link to comment
Share on other sites

Roy, can you explain why the minus speaker wire lead is connected to the #1 terminal which is in series with the crossover components (e.g. caps and inductor)?

This is contrary to 'normal' crossover topologies where the plus lead is in series.

Link to comment
Share on other sites

Roy, can you explain why the minus speaker wire lead is connected to the #1 terminal which is in series with the crossover components (e.g. caps and inductor)?

This is contrary to 'normal' crossover topologies where the plus lead is in series.

Hi Carl,

I've often wondered about that as well. I believe all of the early AR models were set up in a similar way.

The #1 AR cabinet terminal is almost always connected to the negative side of the drivers, and that side of the circuit usually includes the series capacitors. In the 2ax it also includes the woofer inductor. In the AR-3a and 5, however, the woofer inductor shows up on the more typical + side of the circuit (connected to the #2 cabinet terminal), while the tweeter and mid caps are still on the negative side (connected to the #1 cabinet terminal).

This inconsistency with modern design is probably why there are erroneous schematics floating around. It is not immediately clear to most folks what "1" "2" and "T" represent on the back of these beasts. After opening them up it is easy to assume the series components are on the + side of the circuit. Things can become even more confusing when pots are being replaced with l-pads because the soldering post numbers do not match. :)

Maybe Tom or Ken will have some insight....

Roy

Link to comment
Share on other sites

The diagram is incorrect. I've drawn over it using the wire colors to make it easier to discuss.

I also went back and changed the pot terminal labeling in my first response which was not correct relative to your wiring diagram. The #1 pot terminal, however, should be on the right when looking at it from the perspective you have drawn, which is what confused me. It is correctly depicted in the drawing below.

Let me know if the revisions make sense to you. Sorry for the mess of colored lines, but it was the most expedient way to correct your drawing. I've also attached a photo of a 2ax crossover a forum member sent awhile back. The caps are the only changes that were made to it. (The cabinet terminals are labeled in white, and the pots in red.)

The third photo is to clarify my comments about the pot terminals.

Roy

post-101150-1290052950.png post-101150-1290052958.jpg post-101150-1290054523.jpg

The actual design could hardly be more simple. The drawing could hardly be more complicated and confusing. Each speaker has a single filter element in series with it, the woofer has the coil in series, the midrange has a 6mfd cap in series with the plus side of a pot, the minus side is the common. The midrange is wired between the wiper on the pot and the common. The tweeter is wired exactly the same as the midrange except the cap is 4 ohms. All of the drivers are in phase. What's confusing is the order they're drawn in and that the whole thing is upside down. Using a dual section capacitor instead of two separate caps only made it even more confusing. Redraw it yourself with two caps instead of one and you'll see how easy it really is. When you do, wiring it correctly is a cinch. I had to do that myself. I've often wondered why so many designers turn something so simple into something so seemingly incomprehensible until you take it apart and rearrange it after which it becomes obvious what they meant.

Link to comment
Share on other sites

The actual design could hardly be more simple. The drawing could hardly be more complicated and confusing. Each speaker has a single filter element in series with it, the woofer has the coil in series, the midrange has a 6mfd cap in series with the plus side of a pot, the minus side is the common. The midrange is wired between the wiper on the pot and the common. The tweeter is wired exactly the same as the midrange except the cap is 4 ohms. All of the drivers are in phase. What's confusing is the order they're drawn in and that the whole thing is upside down. Using a dual section capacitor instead of two separate caps only made it even more confusing. Redraw it yourself with two caps instead of one and you'll see how easy it really is. When you do, wiring it correctly is a cinch. I had to do that myself. I've often wondered why so many designers turn something so simple into something so seemingly incomprehensible until you take it apart and rearrange it after which it becomes obvious what they meant.

I agree SM regarding the confusing nature of the schematic. Although the dwg. looks like a 'home made' effort and not an AR originated document.

What's your take on having the neg. speaker wire attached in series with the caps and inductors?

Link to comment
Share on other sites

Mantis,

As Roy pointed out, your diagram was incorrect. Here is a copy of the back label, in case yours are missing. Note that the strap goes between 2 & T, NOT ! & 2.

Good luck

Kent

post-101828-1290260953.jpg

Link to comment
Share on other sites

The actual design could hardly be more simple. The drawing could hardly be more complicated and confusing. Each speaker has a single filter element in series with it, the woofer has the coil in series, the midrange has a 6mfd cap in series with the plus side of a pot, the minus side is the common. The midrange is wired between the wiper on the pot and the common. The tweeter is wired exactly the same as the midrange except the cap is 4 ohms. All of the drivers are in phase. What's confusing is the order they're drawn in and that the whole thing is upside down. Using a dual section capacitor instead of two separate caps only made it even more confusing. Redraw it yourself with two caps instead of one and you'll see how easy it really is. When you do, wiring it correctly is a cinch. I had to do that myself. I've often wondered why so many designers turn something so simple into something so seemingly incomprehensible until you take it apart and rearrange it after which it becomes obvious what they meant.

I think Mantis has run for the hills.:) He was simply trying to clear up some of the polarity questions regarding the 2ax wiring, which has also come up in other audio forums. Trying to describe non-conventional arrangements like the old AR crossovers, as simple as they may actually be, can be tricky.

For example, in SM's description above, the statement that "the midrange is in series with the plus side of the pot, the minus side is the common" is misleading. There is nothing "plus" about the #1 pot terminal as wired in the 2ax, and the #2 (common) pot terminal is wired on the positive side of the circuit. The pots are not labeled plus or minus, and have no inherent polarity. They are labeled/embossed "1", "2" , and "B". The #2 and #1 pot terminals will act in exactly the same manner, with the exception of the "increase"/"decrease" rotation direction....and #1 pot terminal of these AR speakers happens to be entirely wired on the negative side of the circuit. In other words, not only are the caps in series on the negative side, so is the variable series resistance provided by the pot wiper. This is the basis of Carl's question.

BTW, I know SM meant 4uf instead of "4 ohms" for the tweeter cap, but just wanted to clarify this as a typo for any novice reading this thread.

Other tricky aspects of the AR-2ax :

1) In the earlier version, the orange dome tweeter leads are not crossed under the tape on the faceplate, and the polarity of the tweeter is uncertain.

2) In later versions with ceramic magnet woofers, the midrange dcr is 9 ohms, not 6 ohms, but looks exactly the same. There is NO way to know without measuring (although some transitional mids had a 3 ohm series resistor mounted on the magnet).

Roy

post-101150-1290270328.jpg

Link to comment
Share on other sites

For example, in SM's description above, the statement that "the midrange is in series with the plus side of the pot, the minus side is the common" is misleading.

Roy

...too late to edit my last post. After reading SM's comments again, it appears his pot wiring statement would be in accordance with Mantis' drawing. As discussed, it is the drawing that is off. My apologies, SM.

Roy

Link to comment
Share on other sites

All is well, I had accidentally drawn the jumper on the wrong terminals. Evidently the problem was that the tweeter leads did need to be reversed, it eliminated a really nasty tinny effect and everything merges properly. Additionally, I was able to uncover a problem with the fiberglass cover over the midrange driver that was causing it to distort. Solved, solved, and solved. Thanks guys!

Link to comment
Share on other sites

All is well, I had accidentally drawn the jumper on the wrong terminals. Evidently the problem was that the tweeter leads did need to be reversed, it eliminated a really nasty tinny effect and everything merges properly. Additionally, I was able to uncover a problem with the fiberglass cover over the midrange driver that was causing it to distort. Solved, solved, and solved. Thanks guys!

That is good news.

Thanks for the update!

Roy

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

×
×
  • Create New...