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Accurate AR-4x schematic


Guest chimpetus
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Guest chimpetus

I believe that the AR-4x schematic that has been floating around both here and on AK may be inaccurate. I believe the colors on the tweeter leads are reversed which would result in reversed polarity on the tweeter.

I've come to this conclusion by observing the attached picture. As you can see, the lead from the base is green. This contradicts the schematic. You'll also note that two leads running to pin 2 on the rheostat are green and yellow. Per the schematic, they would both be green.

Now there is one unknown... whether the speaker in the attached has been modified and is itself, incorrect. Unfortunately, I did not take a picture of the innards of my 4x so I have nothing to compare against.

Thank you for your help.

http://www.classicspeakerpages.net/dc/user_files/2558.jpg

post-102617-1186433871.jpg

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Chimpetus:

What is important is the phase relation between the two drivers and their matching speaker.

The positive terminal of the woofer (red dot or cross) should connect to the #2 speaker input terminal.

#1 terminal of the potentiometer should connect to the #1 speaker input terminal (common or negative side).

"B" terminal (the wiper) of the potentiometer should connect to the tweeter terminal marked with a dab of yellow or white paint on its backside. (That terminal should be the left-most tweeter terminal as viewed from the tweeter backside.)

#2 terminal of the potentiometer should connect to the capacitor and one side of the tweeter.

Before you reverse those wires on the potentiometer, please remove the tweeter and see if someone changed the factory color code at the driver as well. If both reversed, all is fine; if not, fix. Electons don't really care what color insulation keeps them in line :-)

Cheers,

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Guest chimpetus

You're a saint. This is why I prefer schematics over pictures. Had I more than one to reference I wouldn't have questioned the validity of this one.

Many thanks.

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  • 1 month later...
  • 10 years later...

I opened up an AR4x which, I believe was untouched since its creation. It's serial number: 84366  (1966, I believe). The crossover I opened up was the same as the picture EXCEPT the yellow wire running to the tweeter was on the level control's base, and conversely both wires running to terminal 2 on the level control were green. 

I understand that AR changed it's crossover design a few times and one of  those changes was to run the tweeters out of phase with the woofers.  Rumor or truth, I know not. All I know is that my speakers were apparently congruent with the crossover schematic posted above, not the photo. 

 

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  • 3 years later...

I recently questioned that "alternate" AR-4X wiring configuration before coming across this older post.

My 4X speakers (serial FX74042 and FX74072) have the original wiring exactly like the photo - not the schematic - with the yellow tweeter wire and green capacitor wire both soldered to potentiometer terminal 2, and the green tweeter wire soldered to terminal B.

Since my original 4X tweeters have since disappeared, I have no way to tell whether or not the tweeter wires were simply switched during production with the green wire (instead of yellow) being the positive wire soldered to pot terminal B.

RoyC was nice enough to recommended that I wire my crossovers like the originals, but I'm wondering if it makes sense to rewire the crossovers using the schematic. I'm using new Parts Express phenolic tweeters and L-pads so I'll at least know that the yellow wire will run from the tweeter's terminal lug (marked +) to L-pad terminal B, and the green capacitor and tweeter wires will go to L-pad terminal 2.  

 

 

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