Cool, thanks!
the receiver I had was a Panasonic HA-something. Pretty cheapo, especially to the standards that those who frequent this site have. Not a "properly-designed" amp, I don't think. One of the front speaker outs stopped working, and some feedback I got on this site (and/or AudioReview forums) led me to believe it could have been a result of powering the AR-3As, (sometimes at high volumes).As a mid-fi guy :) I feel I have to say something here.
IMO as far as the receiver burning out a channel, it's not that the Panasonic was improperly designed, it's that it was trying to operate a speaker system it was never designed to operate (to their full potential anyway) in the first place.
Speakers such as these ARs demand a lot of current i.e. "amperage" to sound their best and providing large amounts of current requires:
1) a large power supply transformer
2) large power filtering capacitors (those can-like components seen through the top grill, usually located near the transformer)
3) heavily-built power output transistors and a large heatsink that allows them to get rid of the heat they generate.
These items are THE most costly parts and systems, particularly the power supply section, in a receiver.* To keep the receiver affordable i.e the 200 to $500 price point region that Panasonic deals in, the manufacturer simply cannot include such things AND maintain a competitive price. And if those ARs were still being sold new, Panasonic would not expect the buyers of such a speaker at its price point to use one of their receivers to power them: that would be like using a $90 tire on a Mercedes SL V8-powered coupe when in reality, that tire was actually designed to be used with a 4-cylinder Toyota Celica GT.
Then you have to add in the AR's very low efficiency (mostly due to its acoustic-suspension design which enables it to produce very extended bass frequencies for its size) and you've got one heck of a load to deal with!
Recently I had a chance to buy some older Infinitys (
http://www.infinity-classics.de/infinity/models/Reference-series-1+b-2-10+A+B-1981-86/Reference-Standard-4/body_rs_4.html) with similar low impedance issues (though their sound is much different than the ARs, which I find to be too laid back and veiled for my taste), but I don't own an amp capable of driving them properly without frying its own output transistors, so I had to pass on them.
Lastly, with my own Technics SA-DA8 receiver which is a Panasonic product, a couple years ago just for the heck of it, I connected in parallel my Boston Acoustics CR9 bookshelfs (8" ported woofer) and a pair of Infinity bookshelfs (6.5" ported woofer). The BA's impedance of 8 ohms and the Infinity's 6 ohm impedance together were much lower than was stated as a safe load in the receiver's manual but despite that - most probably that warning was one of those cover-your-arse legal things - for several minutes I operated this $350 receiver at 75% of full volume (much louder than I ever listen) AND without its low-impedance mode activated.......and experienced no problems, mechanically or sonically-speaking though excessive heat build up over time might have become a problem but I was too chicken to find that out! :D Anyhoo....but then again these speakers both had an SPL rating of 91dB, much higher than most 70s-era acoustic suspension speakers. I did the same test with my old Pioneer SX-6 bought new in 1983 with the same result.
So the synergy issue that is mentioned on audio forums is definitely at work here i.e. the right amp for "X" speakers makes for better sound.
* transformers use a lot of iron and copper wire. Iron and in particular copper, are becoming very expensive these days and manufacturers have to pass on their cost to us. This is also the reason the theft of such metals is on the rise (even to the point of stealing wire from street lamps!)
