by EWBrown » Thu Sep 04, 2008 2:05 pm
AR-2s (and AR-3As) really need some fairly hefty power, and as I recall, ST70s were a popular power amp for these speakers, and far better sounding than the sand amps of that era. Definitely, 6EM7 or 6B4G SET power levels just won't get the job done with these hugely inefficient speakers. Free is always good, go for them.. Getting the grilles off can be a bit opf a challenge, but I'm more than sure that you can handle it easily Yellow_Light_Colorz_PDT_01
There are many upgrades and repairs listed all over the internet, and crossover modifications & improvements. The old beeswax paper % foil xover caps can go bad, as well as those pots...
AR tended to use "non-standard" size drivers, so simply replacing them with the latest offerings from Parts Express, Madisound or MCM can be a bit of a problem... However, the AR4s used more or less standard sized 8 inch woofers, I once repaired a set of these (the owner's rugrats poked pencils onto the cones) and I used some generic 8 inch acoustic suspension woofers, and replaced the "holed" tweeters without having to revert to major woodworking / surgery to fit them.
The crossover level pots do indeed corrode, and get to the point where vigorous "shaft wiggling" will not help the wipers to make contact.
I recently gave away a pair of AR3As with the "pot ptoblem", they otherwise looked near perfect, no scratches or dings and the drivers were all still perfect condition. The x-over pots were absolutely, totally shot.
If you come across any 1950s vintage AR-1s, they can contain a real "treasure", the tweeter was actually an Altec-Lansing 755A 8 inch, full range speaker, and these go for serious "crazy money" on e-bay.
The 755A was isolated in its own "sub-enclosure", in order to prevent the back pressure from the woofer from affecting . The 755A can be a real "pain" to extricate, without causing damage, but it is well worth the effort. Some of the AR-1s apparently used a western electric full-range as well, these same speakers were often used in the old school "audio-visual" 16 mm movie projectors.
I can only wish that I kept those two old 16MM "yard sale special" movie projectors, that I had back in the early 1980s Yellow_Light_Colorz_PDT_02 Yellow_Light_Colorz_PDT_13 Yellow_Light_Colorz_PDT_09 :o Yes, they had the "good" speakers, but then, I didn't know any better back then... D'Oh!....
/ed B
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