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AR-9 high mid range driver help


Guest David in MA

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Guest David in MA

To all,

I just found out that one of my hi-mid range driver maybe no good. I'm referring to the "1.5" liquid-cooled dome upper midrange driver with semi-horn" as described in the AR-9 section.

I noticed that the music was not in balance: it was louder on the right channel. Just to confirm, I swapped the two hi-mid range drivers and now the sound is louder on the left channel. So, I believe that one of the hi-mid range is no good.

My question is where can I get an original part replacement? If that's not possible, are there any replacements that I can use in place of these drivers?

Your help is much appreciated.

Thanks.

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Guest dogmeninreno

Hello, There is a fellow on ebay that may be able to assist you..His handle is "Vintage AR". I have delt with Larry on several occasions and been well pleased. He also lists refinishing kits, grill cloth, grill mounting pins and so on...Good luck, Dale

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I had to replace an upper mid as well about 2 years ago. Somehow, the voice coil had popped out of the magnet groove leaving the driver quite dead. The first replacement I received was an original AR replacement and was bad out of the box. From the contour of the cone, it appeared its voice coil had not been inserted into the magnet groove on assembly. The second replacement worked, but was not an "exact" replacement. It's semi horn was black rather than the original bare aluminum. As far as my ears can tell, it matched the other driver and I'm not complaining.

Moral of the story, just because it's an original replacement part won't mean its good.

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Guest David in MA

>Just wondering if your search was successful.

>

Yes. Larry (vintage-ar) sent me an email that he had them. I will let you know when I get it from him and test it out.

Also, I noticed that on "very" rare occations, I hear a slight buzz on the "good" high mid range. Is this a bad sign?

Thanks.

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Guest David in MA

>I had to replace an upper mid as well about 2 years ago.

>Somehow, the voice coil had popped out of the magnet groove

>leaving the driver quite dead. The first replacement I

>received was an original AR replacement and was bad out of the

>box. From the contour of the cone, it appeared its voice coil

>had not been inserted into the magnet groove on assembly. The

>second replacement worked, but was not an "exact"

>replacement. It's semi horn was black rather than the original

>bare aluminum. As far as my ears can tell, it matched the

>other driver and I'm not complaining.

>

>Moral of the story, just because it's an original replacement

>part won't mean its good.

I was wondering about this too. I would think that if I can find a pair of upper mid drivers which matching frequency response, it should sound very close to the original. Perhaps someone can comment?

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I read this story some time ago about the upper midrange where the voice coil had popped out of the gap, and having seen the crossover schematic wondered how enough low frequency energy could get to the driver to cause this. Caps that have lost their form and have increased capacitance and leakage are the answer. Just changing the driver is not the complete solution, in fact it will probably fail again if played at high levels. Systems with leaky caps are going to present a much more difficult load to the amp which could compound the problem.

It would be good to save failed drivers for reverse engineering and analysis at some point.

Pete B.

>I had to replace an upper mid as well about 2 years ago.

>Somehow, the voice coil had popped out of the magnet groove

>leaving the driver quite dead. The first replacement I

>received was an original AR replacement and was bad out of the

>box. From the contour of the cone, it appeared its voice coil

>had not been inserted into the magnet groove on assembly. The

>second replacement worked, but was not an "exact"

>replacement. It's semi horn was black rather than the original

>bare aluminum. As far as my ears can tell, it matched the

>other driver and I'm not complaining.

>

>Moral of the story, just because it's an original replacement

>part won't mean its good.

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Guest David in MA

>>I hear a slight buzz on the "good" high mid

>range. Is this a bad sign?<

>

>Sorry if I sound like a broken record. Did you recap them,

>David?

>

No I didn't. I am going to do it sometime in the future. Would recaping make this buzz go away?

Thanks.

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>No I didn't. I am going to do it sometime in the future. Would recaping make this buzz go away?<

It really has a better chance of making that buzz go away than you might think.

Those bad caps are *very likely* putting lower than designed and can be tolerated frequencies through those upper midrange drivers. The worst offending capacitors found during replacement were the upper midrange caps.

Those drivers, in particular, were designed with special ferrofluid because "ordinary" drivers with ferrofluid "boiled away" the ferrofluid. (this is from an article in the Library) They already take a beating, by design.

So yeah, you quit making them play frequencies lower than they were designed-for and the buzz may stop.

Bret

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Guest David in MA

>>No I didn't. I am going to do it sometime in the future.

>Would recaping make this buzz go away?<

>

>It really has a better chance of making that buzz go away than

>you might think.

>

>Those bad caps are *very likely* putting lower than designed

>and can be tolerated frequencies through those upper midrange

>drivers. The worst offending capacitors found during

>replacement were the upper midrange caps.

Good point.

>

>So yeah, you quit making them play frequencies lower than they

>were designed-for and the buzz may stop.

Yeah, I guess I'll need to go back and look up the topics on caps needed for AR9 cap replacements.

Thanks.

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David,

You might consider bringing your 9s down to ABTech in Hopedale for a evaluation. ABTech is ARs national warranty service center, and have all the parts necessary to restore your 9s to peak perfomance. They did a great job on my AR-3As. I'll be bringing my 9s there next week for a look-see. Good luck!

Dana in Framingham

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>look up the topics on caps needed for AR9 cap replacements<

The capacitor in parallel with the upper midrange is listed as a 6uF, it isn't. It's an 8uF. The error was caused by an indistinct copy of the plans.

Bret

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Guest David in MA

Dana,

>You might consider bringing your 9s down to ABTech in Hopedale

>for a evaluation. ABTech is ARs national warranty service

>center, and have all the parts necessary to restore your 9s to

>peak perfomance. They did a great job on my AR-3As. I'll be

>bringing my 9s there next week for a look-see. Good luck!

Thanks for your info. I hope it's within my budget...what work was done on your 3A's and how much did it cost you? Please let me know.

Thanks.

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Guest David in MA

>>look up the topics on caps needed for AR9 cap

>replacements<

>

>The capacitor in parallel with the upper midrange is listed as

>a 6uF, it isn't. It's an 8uF. The error was caused by an

>indistinct copy of the plans.

>

Thanks for the note. At this point, I'm thinking about having ABTech take a look at the speakers. If it is within my budget, I might go for it. If it is too expansive, I will just have to recap them myself...

Thanks.

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David,

AB Tech replaced the tweet in one of the AR3As with the latest production AR tweeter, and all pots in both speakers for around a couple hundred.

Oddly enough I was just reading a post by James McShane whose uncle was head of R&D with AR, and he recommends eliminating the tweeter pot altogether to raise tweeter output, and secondly replacing both mids due to wire breakage.

Carlos at AB Tech will test all your drivers and make recommendations based on his results. Good luck!

Dana

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>>> Oddly enough I was just reading a post by James McShane whose uncle was head of R&D with AR, and he recommends eliminating the tweeter pot altogether to raise tweeter output, and secondly replacing both mids due to wire breakage. <<<

Which post was that?

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I did rebuild the crosovers, so it's not likely to happen again due to old caps. What it doesn't explain is how I had the luck of receiving an exact replacement with the same problem out of the box.

Just as a note. The only difference in the replacement driver was it's black rather than bare aluminum silver. Oddly, they originally apologized for sending the silver one thinking it wasn't an exact replacement.

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Guest David in MA

>>I'm thinking about having ABTech take a look at the

>speakers<

>

>Why? If you want them to sound like AR-9s when you are

>finished, they can't help you.

I guess I meant I would consider them to recap crossover...I can do it but I'm not sure what sort of time committment is required.

As is, the AR9's sound terrific, although there is a less mid from one of the drivers. I figure I should recap first. Should I do it myself?

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