AR-7 Crossover Diagram

[AR_nut_in_Oregon]

I just updated my AR-7's Xover caps last night. Used Dayton poly 6.2 MFD, 5%, 250v...(original value was: 6MFD)

While I had the boxes open, decided to document the wiring (see attached)....

Noticed that the Woofer's Red lead was connected to a clearly marked "+" terminal on the driver, and the Tweeter's Yellow lead was connected to a clearly marked "+" terminal on the driver. However, the Woofer's "+" connects to Terminal number "2" input, while the Tweeter's "+" connects to Terminal number "1". Does'nt this put the the drivers out of phase with each other, or is this normal?

Also sealed the Woofers and Tweeters by applying silicone under the foam gaskets and lightly tightening the mounting screws so as to not squeeze it all out. Will check tightness again when I'm sure that the silicone is fully cured. It did make a noticeable difference in their sound...they just sound tighter....hard to put into words.

AR_7_Crossover.pdf

[genek]

Noticed that the Woofer's Red lead was connected to a clearly marked "+" terminal on the driver, and the Tweeter's Yellow lead was connected to a clearly marked "+" terminal on the driver. However, the Woofer's "+" connects to Terminal number "2" input, while the Tweeter's "+" connects to Terminal number "1". Does'nt this put the the drivers out of phase with each other, or is this normal?

Looks that way to me, but I'm schematic-challenged. Whether it's normal or not, don't know. Maybe try reversing something and see how it sounds?

[KlausDK]

Noticed that the Woofer's Red lead was connected to a clearly marked "+" terminal on the driver, and the Tweeter's Yellow lead was connected to a clearly marked "+" terminal on the driver. However, the Woofer's "+" connects to Terminal number "2" input, while the Tweeter's "+" connects to Terminal number "1". Does'nt this put the the drivers out of phase with each other, or is this normal?

Hi AR_nut

This is what it should look like, to the best of my knowledge, normally red and yellow goes to plus, but I have frontwired tweeters on my AR-7, so I am not sure which is plus. Still puzzled as to why the resistor is placed after the capacitor, this will change the X-overfreq. when tweeter is attenuated.

BRgds Klaus

[genek]

Still puzzled as to why the resistor is placed after the capacitor, this will change the X-overfreq. when tweeter is attenuated.

I think this is pretty much the same thing that happens when you turn down the level controls of an AR speaker with pots. The Aetna-Pollaks are variable impedance and their resistance increases. Does anyone with better understanding of crossovers than I have know whether the freq goes up or down?

[AR_nut_in_Oregon]

Hi AR_nut

This is what it should look like, to the best of my knowledge, normally red and yellow goes to plus, but I have frontwired tweeters on my AR-7, so I am not sure which is plus. Still puzzled as to why the resistor is placed after the capacitor, this will change the X-overfreq. when tweeter is attenuated.

BRgds Klaus

Klaus,

Thanks for the pic....that is exactly how mine are wired. My representation of the switch may not be correct...my VOM does not have a fine enough resolution (scale) to measure the resistance across the switch terminals in both positions (was reading as dead short-circuit regardless of the switch position). I checked my schematic again and the resistor is wired after the capacitor. Maybe someone can shed some light on that.

[genek]

Thanks for the pic....that is exactly how mine are wired. My representation of the switch may not be correct...my VOM does not have a fine enough resolution (scale) to measure the resistance across the switch terminals in both positions (was reading as dead short-circuit regardless of the switch position). I checked my schematic again and the resistor is wired after the capacitor. Maybe someone can shed some light on that.

Here's the crossover for the AR-3a. As you can see, both level pots are wired between the drivers and their associated capacitors. From what I can see, most AR crossovers of the classic era are wired this way, with occaisional bits added at the drivers as time passed and drivers were changed. Your crossover merely substitutes a switch and two resistor options (3 ohms and none) for a variable resistor.

Does the tweeter balance change when you flip the switch? If not, your switch reading dead short in both positions could mean it really is shorted.

[AR_nut_in_Oregon]

Your crossover merely substitutes a switch and two resistor options (3 ohms and none) for a variable resistor.

Does the tweeter balance change when you flip the switch? If not, your switch reading dead short in both positions could mean it really is shorted.

Gene,

My $10.00 VOM just won't read that small (3 ohm) of a value...there is only one scale for ohms on it (x1K) so it is difficult to discern the difference between zero and just barely off zero. Gonna have to get a battery for my trusty Simpson 260 I guess.

To answer your question....yes, the tweeter level does change when the switch is operated. I was just trying to determine which position the switch was in for "Flat" or "Normal"...i.e. open or closed. I could see what looked like the contact plate move through a small opening in the switch and am guessing that the switch shorts out the resistor in the "Flat" position.

[Robert_S]

I was just trying to determine which position the switch was in for "Flat" or "Normal"...i.e. open or closed . . . guessing that the switch shorts out the resistor in the "Flat" position.

The following is a cropped section of the file "AR-Drawing270.TIF" [Drawing No 206013], from the Library, in the "AR Drawings Index in Adobe Flash Format" section, which is titled "AR-4xa, 6, 7, 8 | 100004/6/7/8 | 1-1/4-in HR", as shown below (I can't link directly to the file due to the limitations of the 'Flash' format, hence the low-resolution crop enclosed):

It would appear to confirm your guess as being correct.

Robert_S