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Got some Boston Acoustics A100s and A200's and a Speaker Lab Question

sealy

sealy

Addicted Member
Picked up two pairs of Bostons yesterday - A100s and A200s for $75 total. Both pairs are in very nice shape. The woofers of both pairs need re-foaming. Griles and logos are intact. The woofers of each model, although of the same diameter are distinctly different. The A100 woofers have smaller voice-coils and conventional vented circular magnets, while the A200 woofers have larger voice-coils and square magnets. Interesting.

The A200s are of a very unique design, as many probably know. Very thin front-to-back, but quite wide and meant for wall placement. Built like a tank and surprisingly heavy. I've not owned a pair of either model and am thus looking forward to hearing them. The tweeters on the two models are also different. I can't identify the tweeters in the A100s, although they are stamped Boston on the rear. Could they be a proprietary design?

The tweeters on the A200s look to me like SEAS, although I could be mistaken.

Now the Speakerlab question. The same seller had a pair of medium size Speakerlabs which appear to be a 4-way design. On the bottom is a woofer, then above that a smaller woofer. Above that is a cone mid, then a dome tweeter, which appears to be a doped Philips model is at the top.

On the rear of the speakers there are 3 toggle switches - one for mid, one for treble and one for "woofer damping." The last switch designation has me curious.

Is this speaker designed around the Nestorovic bass-loading principle? And, is this switch used to tailor bass response between the two drivers?
 
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Based on the square magnets and Seas tweeters, I'd say that your A200s are earlier than your A100s. AFAIK the newer tweeters are Boston's own design.
 
Interesting. The date stamp on the woofers of the A100s say 1982, I believe(although it could be 1988, they're a bit smudged).
 
For their first few years in business, Boston used the round SEAS tweeters in models A70 and up. Then came the proprietary tweeter, though I think I remember once being told that the dome itself was sourced from SEAS.

Also, earlier woofers had paper cones and later ones had black poly cones. I can't recall if the changes to the woofers and the tweeters happened at the same time.

But I think it's safe to say that if your A100 woofers are paper, then the smudged date is likely '82. In fact, it may be that the A100s were discontinued by '88. It was somewhere around that time, at any rate.
 
Octaven said:
For their first few years in business, Boston used the round SEAS tweeters in models A70 and up. Then came the proprietary tweeter, though I think I remember once being told that the dome itself was sourced from SEAS.

Also, earlier woofers had paper cones and later ones had black poly cones. I can't recall if the changes to the woofers and the tweeters happened at the same time.

But I think it's safe to say that if your A100 woofers are paper, then the smudged date is likely '82. In fact, it may be that the A100s were discontinued by '88. It was somewhere around that time, at any rate.
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They are indeed paper, as are the A200 woofers. I ran the A200 mids and tweeters with the woofers removed. The sound seems very clear and smooth.
 
GuyK said:
The SpeakerLabs you describe sound like the S30's, and if so I believe are a Nestorovic design. I found an earlier thread here on AK.

http://www.audiokarma.org/forums/showthread.php?t=148435

The OP in this thread has drawn the XO circuit. I have not studied it, and am not able to comment on the toggle for "woofer damping".
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Thanks for the information. I looked at the thread and those are indeed the speakers I saw. For 30 bucks, I may as well buy them. Lots of re-foaming to do.
 
My A70's from 1980 (first year manufactured) have woofers with square magnets and paper cones. The tweeters are round SEAS. You have an early model there.
 
The A200s are real sleepers in the marketplace. Fantastic speakers that perform far beyond their used price point.
 
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