Newbie: When to refurbish AR 4x speakers

amplifiers, receivers and loudspeakers
billsea
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Re: Newbie: When to refurbish AR 4x speakers

Post by billsea » 23 Jan 2019 18:21

Thanks! It is capacitor time! I have Carli 20 uF caps. I assume the wire coming out of each end is comparable to the terminals on top of the old silver Sprague. The two wires soldered to the bracket holding the Sprague must be ground?

jdjohn
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Re: Newbie: When to refurbish AR 4x speakers

Post by jdjohn » 24 Jan 2019 01:42

Hi Bill,

Call me a snob (or other appropriate descriptor), but I would recommend you go with a better capacitor than the mylar Carli cap :shock: These vintage AR speakers are well worth the added expense of a (IMO better) poly-film crossover capacitor. And seeing as how there is only one per speaker, you can afford to splurge a bit. A Solen brand capacitor is a good one that won't break the bank, or even a Dayton would be better than the mylar Carli.

Having said that, since these types of capacitors are typically non-polar, it won't matter which wire is soldered to which capacitor lead. Also, there is no 'ground' when working with speaker terminals - there is only + and -. The two wires joined on the bracket are merely a junction, not a grounding situation. In fact, that bracket may need to be removed or cut away in order to install the new capacitor. No worry, though, the cap can be hot-glued to the masonite board, or secured with a zip-tie, etc.

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Re: Newbie: When to refurbish AR 4x speakers

Post by Spinner45 » 24 Jan 2019 02:19

jdjohn wrote:
24 Jan 2019 01:42
Hi Bill,

Call me a snob (or other appropriate descriptor), but I would recommend you go with a better capacitor than the mylar Carli cap :shock: These vintage AR speakers are well worth the added expense of a (IMO better) poly-film crossover capacitor. And seeing as how there is only one per speaker, you can afford to splurge a bit. A Solen brand capacitor is a good one that won't break the bank, or even a Dayton would be better than the mylar Carli.

Having said that, since these types of capacitors are typically non-polar, it won't matter which wire is soldered to which capacitor lead. Also, there is no 'ground' when working with speaker terminals - there is only + and -. The two wires joined on the bracket are merely a junction, not a grounding situation. In fact, that bracket may need to be removed or cut away in order to install the new capacitor. No worry, though, the cap can be hot-glued to the masonite board, or secured with a zip-tie, etc.
I usually fasten bigger caps in place with Permatex grey gasket sealer.
It's strong, stays pliable, makes replacing easier if needed.
Hot glue can come un-done sometimes, letting the cap rattle on bass notes.

phivates
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Re: Newbie: When to refurbish AR 4x speakers

Post by phivates » 24 Jan 2019 02:23

Agree about the hot glue; have seen many failed crossover assemblies that asked too much of it. It does work at first though.

AsOriginallyRecorded
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Re: Newbie: When to refurbish AR 4x speakers

Post by AsOriginallyRecorded » 24 Jan 2019 02:49

It's a shame that the tear went all the way to the center cap. I've seen and personally repaired a few paper cone speakers with small tears by using carpenter's glue and paper coffee filters cut to fit. As a short term fix only, but I could not tell the difference between repaired and good original speaker. Of course, the likelihood of original performance and sound is virtually guaranteed with a re-coning. Although the cost may raise eyebrows, having acquired the speakers cheap will tend to help rationalize the investment to re-create a pair of classic speakers like these. As long as you plan to keep and enjoy them, a solid investment in sound.

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Re: Newbie: When to refurbish AR 4x speakers

Post by jdjohn » 24 Jan 2019 04:06

Has there been a stress test between adhesives for this application? I think the real challenge is what adheres best to masonite board.

I recently serviced a pair of AR-2ax, and used hot glue to adhere zip-tied pairs of Solen capacitors to the board/cabinet. I held the caps securely to the board while the glue cooled. After cooling, I gave them a good tug, and it all seemed secure to me.

What would Spinner45 say about people who obsess about such things? :D

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Re: Newbie: When to refurbish AR 4x speakers

Post by Spinner45 » 24 Jan 2019 04:40

jdjohn wrote:
24 Jan 2019 04:06
Has there been a stress test between adhesives for this application? I think the real challenge is what adheres best to masonite board.

I recently serviced a pair of AR-2ax, and used hot glue to adhere zip-tied pairs of Solen capacitors to the board/cabinet. I held the caps securely to the board while the glue cooled. After cooling, I gave them a good tug, and it all seemed secure to me.

What would Spinner45 say about people who obsess about such things? :D
All I know is that I've seen my share of loose parts in crossovers due to the hot glue loosing its grip, rattles, etc.

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Re: Newbie: When to refurbish AR 4x speakers

Post by jdjohn » 24 Jan 2019 04:47

I think it depends on how the speakers have been treated during transport. Hot glue should be fine if the speakers are treated properly during moving. If they are banged-around, all bets are off.

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Re: Newbie: When to refurbish AR 4x speakers

Post by Spinner45 » 24 Jan 2019 06:31

jdjohn wrote:
24 Jan 2019 04:47
I think it depends on how the speakers have been treated during transport. Hot glue should be fine if the speakers are treated properly during moving. If they are banged-around, all bets are off.
That is likely true.
When I have to get inside a system to do re-capping, or rattle-fixing, I don't want to have to do it again.
Wirewound resistors also get Permatexed tight, those rattle too.

billsea
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Re: Newbie: When to refurbish AR 4x speakers

Post by billsea » 31 Jan 2019 15:50

AsOriginallyRecorded wrote:
24 Jan 2019 02:49
It's a shame that the tear went all the way to the center cap. I've seen and personally repaired a few paper cone speakers with small tears by using carpenter's glue and paper coffee filters cut to fit. As a short term fix only, but I could not tell the difference between repaired and good original speaker. Of course, the likelihood of original performance and sound is virtually guaranteed with a re-coning. Although the cost may raise eyebrows, having acquired the speakers cheap will tend to help rationalize the investment to re-create a pair of classic speakers like these. As long as you plan to keep and enjoy them, a solid investment in sound.
I haven't gotten as far as a getting a quote for a reconing. I have found a little audiophile den a couple of hours away; the proprietor says he won't do reconings, only repairs. He feels that the sound is never to be truly recaptured. I feel no advice is absolute; so many intangible factors come into play. A roll of the dice is needed sometimes. I just wish I had trolled the forums a while before I tried this disastrous patch job. I will post a pic in spite of myself. smh
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A capture just as it entered the black hole, ahhh! To troll long is NOT to troll wrong my newbie friends!
(201.67 KiB) Downloaded 17 times

billsea
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Re: Newbie: When to refurbish AR 4x speakers

Post by billsea » 31 Jan 2019 15:52

Luckily phivates has my back. My AR4x will rise from the ashes.

billsea
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Re: Newbie: When to refurbish AR 4x speakers

Post by billsea » 31 Jan 2019 15:59

I am walking thru a cherry grove of excellent advice and do truly appreciate everyone's input on the capacitors. I have decided to stick with the Carli for two reasons: Roy C. recommended them and the voltage was close to original specs; the third :wink: is it's already here in my hot hand. Is the Carli not a poly film? Overall, it seemed like it was fairly close to original specs with some upgrade along the way. Here is my securement-I used a dab of silicone caulk to hold it down and plan on doing the same to the board unless some chorus of warnings comes after this post.
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Arms open, ready for wiring!
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phivates
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Re: Newbie: When to refurbish AR 4x speakers

Post by phivates » 31 Jan 2019 16:41

Looks good - tywrap plus cushy stickum. Maybe the poly in your caps is -ester instead of -propylene hence the comments

billsea
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Re: Newbie: When to refurbish AR 4x speakers

Post by billsea » 31 Jan 2019 16:52

I see- polyester-that rings of cheapness- and dare I say-bad taste?

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Re: Newbie: When to refurbish AR 4x speakers

Post by Spinner45 » 31 Jan 2019 18:00

I don't understand the long delay with this process.
Those woofers could have been shipped to Bill at Millersound, re-coned, and back in your hands in perfect condition by now.