help

[pantera74l]

Hi;I just got my A-7s today and I'm in the process of putting them together.I need to know on the 806-8a hf drivers which terminal is common?One post on each driver is stamped #1 onthe left from the rear,the other terminal is stamped #2.Help please I'm itchin to listen.Thanks

[Mike Gibson]

On my drivers #1 is positive and #2 is common. Enjoy the music.

Mike

[pantera74l]

Thanks Mike:Is there anyway to tell which is common using a Vom meter Thanks

[pantera74l]

WHOOO HOOO:WHAT SOUND;SWEEET,SWEET MUSIC.These things are fantastic,makes the Cerwin Vegas I was using sound like tin cans.Enough for now,back to the music and a beer.Thanks all for your help

[cclark65]

I know it's hard, but you can actually tell by taping a piece of saran wrap over the throat hole, and applying voltage from a AA battery to the terminals. You'll either see it bulge out or **** in, indicating polarity.

Otherwise, without a polarity tester, I have no clue. Even polarity testers are flaky depending on how far away you hold it from the horn, at least the one I saw being used was.

[cclark65]

darn filters... saran wrap will s u c k in.

[Todd W. White]

This is a carry over from the WE days.

A positive voltage on the "1" terminal produces a compression wave out of the magnetic gap.

Hence, L1 on the woofer would push the cone towards the listener, so you'd connect the positive LF lead to it, the negative to L2.

On the HF compression driver, the diaphragm moves away from the listener when pushed out of the gap, so you'd connect the positive lead to L2, and the negative to L1.

That is, if my memory is correct...

[bigjunglejim]

One must be watchful that the leads inside the driver have been connected properly. I've seen them installed both ways by folks that didn't know what they were doing. When I was going to do my first diaphragm replacement, I was told to check with a battery right after the diaphragm was installed (before the leads are attached) that the dome moved away from from the magnet when the "+" side of a battery was applied to the "+" side of the the voice coil (be sure that is the way it's supposed to go, I don't know if this is true with other manufacturers). I was told to do this so I'd be sure the diaphragm was assembled properly at the factory with the proper markings of "+" & "-". Don't take it for granted, checking is cheap insurance and it can save a lot of headaches later. If you have questions, get the answers from a reliable sorce, such as factory tech notes.

GPA's web site has a pdf file on replacing diaphragms. Just click on "Altec 800-900 Series Diaphragm Replacement Instructions"
Here's a link to the page; http://www.greatplainsaudio.com/downloads.html