Boston Acoustics A200s. Very little sound.

Carl-Netz

Carl-Netz

New Member
Hi!

I have been restoring vintage KLH speakers for a few months now. I found a free pair of Boston Acoustics A200s that needed some foam surrounds. Loving the Kloss sound, I thought I'd give it a try.

Anyway, I replaced the surrounds. First time. It wasn't as bad as I expected.

I replaced the capacitors on one of them and am waiting to do the other while a capacitor is on back-order waiting shipment.

So, super-excited, I hooked the one that I completed up to my system. It produces almost no sound. I am using a Harmon Kardon AVT 145, which puts out 50 watts. Turned all the way, it gives me some nice sound, but not 50 watts worth. Not sure if I messed something up, I connected the other one too. So one has new caps, the other still has the original. Same deal. Not much sound coming out of these. And both of them the same. So it's not my fault messing with the crossover. I'm confident in my recapping work. But I'm nervous and not messing with it anymore until I get some ideas.

What am I missing?
 
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Have you verified that sound is coming from each of the three drivers when playing music? The paper towel holder is valuable for verifying individual drivers. One end to your ear, the other end near the cone of the driver under test.

If you have an ohmmeter, measure the resistance across the speaker terminals. You will be measuring the resistance of the crossover inductor and the woofer. The resistance should be in the ballpark of 6 ohms. If much higher or an open circuit, you need to troubleshoot the internal wiring.

An alternative is to pull the woofer and mid out and connect them directly to a receiver/amp. At low volume levels, that is safe. You should hear sound as you would normally expect at the position of your volume control. If you hear expected sounds, then the problem is either crossover related or a problem with the internal wiring.
 
RTally said:
Have you verified that sound is coming from each of the three drivers when playing music? The paper towel holder is valuable for verifying individual drivers. One end to your ear, the other end near the cone of the driver under test.

If you have an ohmmeter, measure the resistance across the speaker terminals. You will be measuring the resistance of the crossover inductor and the woofer. The resistance should be in the ballpark of 6 ohms. If much higher or an open circuit, you need to troubleshoot the internal wiring.

An alternative is to pull the woofer and mid out and connect them directly to a receiver/amp. At low volume levels, that is safe. You should hear sound as you would normally expect at the position of your volume control. If you hear expected sounds, then the problem is either crossover related or a problem with the internal wiring.
Click to expand...
Hi,

Yes, all of the drivers are producing sound and at very low levels.

The loudspeaker assembled shows 6 ohms. The woofer alone is 0 (open circut?). When I connect the woofer alone to the amp, I get almost no sound. When I used the amp system for centering the cone during refoaming, I noticed there was almost no sound then either. I assumed I was doing something wrong since it was my first refoam. Turns out, maybe the driver was bad. Is it strange that both woofers are shot? I also assumed I was doing something wrong since it was the same for both woofers.

I haven't tried the mid yet. That will be next, after work tomorrow.

Also, wow! This community is amazing. I can't tell you how much fun I'm having and how much more fun it is sorting it out with so much good help.
 
0 ohms is short circuit...
not a nice load if you test it out directly connected to your AVR.
I know you stated that both '' cabinets '' check 6 ohms BUT Do both woofers check zero ohms ?
If not, check tinsel wire ( coming from the connector bracket on the woofer metal frame then thru the cone over to the voice coil )
One could touch the frame and make out a short somewhere.

From what I know, voice coils oftenly go open circuit instead of short.
Does the voice coil scrape when you gently push the cone inward ?

Good luck on frrrrrrree A-200 :)
 
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Thanks so much everyone!

I got them singing. One of the woofers was dead and the reason I was getting a short. So, I replaced it with a nice match from ebay. I still had some issues before realizing that these aren’t like my high efficiency vintage KLH speakers and demand some power.

My impressions are that the mids and highs are beautiful and create a crisp soundstage. I suspect the width of these cabinets compared to the size of the drivers helps boost the low end and somehow opens up the highs. And they fit nicely against a wall.

The bass is definitely there and fills the room nicely without being the center of attention. Overall, these A200s are lovely speakers. I think they will make excellent fronts for a home theater, which I might try.
 
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