Difference between the AR-18 & AR-18s

[Andre]

Good Afternoon,

I would like to know if all drivers from the AR-18 and AR-18s models are all basically the same (voiced the same) and can be interchanged (mixed) between woofers/mid & tweeters.

What I've at this time are, 2 tweeters and 4 woofers in good condition, and missing for now, 2 tweeters, originally from the AR-18

The tweeters model number on the AR-18 are as followed, 2000014-3 and the woofer model number is, 200001-1 with a square magnet with 8 screws attachment

On the AR-18s, the tweeters model number are, 200038-0 and the woofer model number are, 200037-0 with a square magnet and with 4 screws attachment.

At this time, I would like to use all drivers from the AR-18s model, and use them in the AR-18 enclosure model. The difference between the two enclosures are, the 18 use a two way switch and has a resistor with cap, while the 18s box does not and does not have a resistor, just a single cap.

Also, what is the capacitor value on the 18 and on the 18s, are they the same. I can't make out the number on the 18.

The grey cap on the 18s shows this value, 50v 5mfd bi-polar made by Umicon of Japan.

The black cap with the resistor is on the 18,

A few pics showing the difference between them.

Thanks

André

[ra.ra]

Hello Andre.

I am somewhat surprised your post has received no replies yet - - I think there are members here who know the 18 series very well. I do not happen to be one of those members, but perhaps these thoughts may be of some assistance. Whenever I have my own questions similar to yours, I often research the original AR drawings in the Library, which is where much of this response originates.

You have correctly identified the original drivers in the AR-18 and AR-18s, and indeed, the two speaker models do have different part numbers. However, when you compare the specific make-up of the drivers between the two models, you can see that they are very similar in composition and in fact, share many of the same essential sub-components. For example, for the tweeters, they appear to employ the same magnet and both use 325g of ferro-fluid. The only obvious difference is that the 014 tweeter has straight tinsel wires while the 038 tweeter uses an s-shape wiring configuration. I presume this wire shape revision is intended to allow for greater cone movement, resulting in fewer failures. Similarly with the woofers, they have several shared sub-parts, but the universal 001 woofer had a double dust cap and had a DCR spec of 5.0 ohms, while the 037 woofer had a single dust cap and had a DCR spec of 4.6 ohms. Further, the 001 woof was used in several AR models, while the 037 was used in only two.

All that said, I am sure there were intentional minor engineering differences with these drivers and speaker models, but I think at this point these drivers can be considered to be virtual substitutes for one another with restoration efforts. Regarding the cabinets, I do not know if either of these models might have used actual walnut (real wood) veneer, but I suspect at least one of them used the faux walnut vinyl. Also, I believe the 18 had a mis-aligned offset tweeter while the 18s had two in-line drivers.

Last point, regarding the crossover. The two-way switch in the 18 is a nice feature to have, and it does require the resistor to be able to perform its intended switching duties. But since the AR-18 used a 6mf cap while the AR-18s used a 5mf cap, if you want to use the 18s drivers in the 18 cabinets, one suggestion would be to replace that original black 6mf cap with a new 5mf cap to match the drivers and then simply drop in your preferred drivers. Leave the switch and resistor as-is, and I suspect you will then have yourself a very fine pair of small bookshelf speakers. Keep us posted.