Restoring a pair of AR-8 Speakers

[redpackman]

I'd heard of AR-8's. I've restored, variations of AR2's, AR3's and AR3A's, variations of AR4's, AR5's, AR6's (love 'em) and now a pair of AR-8.  I'd never seen a pair of AR-8's in person. 

Yeah, I love AR speakers. 

The AR8's I have are different from the ones I've done before. Reportedly the 8's were produced by AR to answer to the "rock speaker" phenomenon in the early to mid-70's or so and to be financially accessible to the younger crowd.  As a result they are economy speakers with a vinyl veneer covered cabinet (never seen that before in vintage AR). As such unlike earlier vintage AR that strove for absolute fidelity to the original sound, the AR-8 was colored to be a bit bass-heavy and perhaps and what appears to be a long throw 10" woofer (perhaps like the long throw woofer in the AR-6 which punches WAY above it's weight....that's why I like it). I've got restored AR-3a's and the AR-6's are still my wife's favorites.

Anyway, looking at the original crossover. No inductor, just the wires, two resistors (3 ohm I think from memory) and the high, medium and low switch for the tweeter.  Then there are two 5 uf 50v capacitors  wired in parallel (pictured) with both wires soldered together. SO my rudimentary knowledge of such concludes that is identical to one 10 uf capacitor as long as it's rated at 100 v or more. Is that similar to Winslow Burhoe's EPI-100's crossover. Burhoe had worked at AR before starting EPI. Hmmmmmmm............

Is my assumption correct?  And, why would AR do it that way? 

 

Any other comments on the AR8 would be welcome. As I'm in the midst of putting in new surrounds, I haven't heard them yet. 

 

[genek]

Yes, 2 5s in parallel would be the equivalent of a 10. The most likely reason would be cost. Either 5s were a lot cheaper than 10s, or the need for 10s wasn't great enough to justify the cost and effort of stocking them in inventory.

[stimmo520]

I just picked up a pair in fairly decent condition this week too! To my dismay, the original woofers were replaced by Radio Shack polypropylene woofers...guess I dont have to worry about foams anymore. I have a single 10uf cap in these though, same resistors. I got some KLH/Dynaco replacement grill fabric and new Audyn caps. Going to see what I get. May do a new veneer too as every corner is dented. 

 

[stimmo520]

Anyone know where I can find original badges and woofers.....I may go the full restore....one is missing a badge, and wonder what the sonic difference could be with original foam woofers. There is little to know information on the interwebs concerning these speakers....

[genek]

The RS woofers will almost certainly not be well suited to the cabinets. In 1979 AR was supplying the same service woofer for the 8 as for the 2ax, so they should be easy enough to find. Original badges show up on eBay from time to time. Have not seen anyone offering new repros.

[stimmo520]

Thanks Gene! I will dig into the original woofers from the 2ax. I can live without badges...for now.

[stimmo520]

Ordered Service Woofers that were available on Ebay for $100....will see what that yields - Theyll be installed later this week.

[redpackman]

Here's a picture of the back of the original AR-8 woofer from my pair. It's obviously original, though I do not know if they used the same speaker in all AR-8's....or for that matter if the woofer in the 8 is the same as the AR-2.... and AR-5 series though all are 10" woofers. I've read somewhere (authoritative or rumor, I do not know) that the AR-8 woofer was a special design "long throw?" like the 8" woofer in the AR-6. 

 

In AR's own literature about the AR-8 (available on Classic Speaker Page's own database" AR writes "In the AR-8 we have used a 10" woofer that is more efficient that some of our other designs, to produce the higher volumes necessary for rock music..."

It adds later "Average Resonance of Woofer:  Free air 26 hZ;  In enclosure 52 hz". 

I don't know how that compares with the AR-2's many varieties of woofers or the AR-5 woofer. 

http://www.classicspeakerpages.net/library/acoustic_research/original_models_1954-1974/original_models_brochures/ar-8_brochure/ar-8_brochure_pg2.html#previous-photo

 

 

[stimmo520]

Thats very helpful. I ordered These and hope the get these cabinets closer to spec. The foam looks okay, but they definitely look different, not sure if its due to later production being a service unit. 

I did get one of the grilles redid. 

[stimmo520]

Well, the new-old service speakers came in yesterday. Looked like they had been refoamed - one will need to be redone at some point as the glue and surround are on the underside of the cone. I took this opportunity to tighten the original binding posts, seal the cabinet interior, and recapped. The cap I took out was a royalistic 10 uf npe, and replaced with a 10 uf Auyden mkf. When replacing the speakers, I added new gasketing as well. This was fun and the outcome is extremely enjoyable. Ive always liked my Polk Monitor 7Cs, but the AR-8 is really enjoyable and really fills the high to low sonic spectrum. 

 

Thanks for everyone's info on this forum!