Two Observations on Installing the AB Tech Tweeter in the AR-3A

[Charles218]

The AR Restoration Guide recommends the AB Tech Tweeter as the best replacement when an original driver is not available. I've just about completed the installation and wanted to pass on two experiences that I had. First, I was surprised to find that the AB Tech Tweeter did not fit in the cabinet opening, it was slightly too large. The body of the tweeter was a perfect fit, the problem was only where the two connectors are located. Not a major issue, I was just a little surprised when it didn't drop right in.

Also, the restoration guide states that you must add a "0.07-mH 18 gauge air core inductor" to the crossover. It further states that "Audio supply stores currently sell 0.05-mH and 0.025-mH coils, but not 0.07-mH." I was able to purchase the 0.07 spec inductor from Meniscus Audio Group in Grand Rapids Michigan, http://meniscusaudio.com/. You can see on the far right of their homepage that they can custom make any value inductor. I ordered two and the total price was about $8.50 plus shipping. I don't have any connection with Meniscus Audio, just wanted to make this info available to everyone.

[JKent]

Just a quick comment: The restoration manual is © 2007. Since then Roy has done a lot of experimenting and came up with the Hi-Vi Q1R tweeter (at about 1/3 the cost of the AB). And the Hi-Vi does use the 0.05mH coil. I used that combo in my 3a's and it was a drop-in and worked great.

Another mod that Roy suggested was to raise the xo point a bit:

"You can easily reduce the capacitance to 3uf in your 3a's without pulling the woofer by putting a 6uf cap in line *at the tweeter*. This will put it in series with the 6uf cap in the cabinet, reducing the total to 3uf. At that point you should be able to turn the tweeter controls to almost full on instead of 3/4...The result will be greater output at the desired higher frequencies...and less output at lower frequencies."

Here's a photo of mine with the Hi-Vi tweeter and AR-11 midrange.

Meniscus is a good resource.

Kent