Acoustic Research Potentiometer Restoration Guide (VERY LONG, with photos)
- Thread starter tmad40blue
- Start date
aidynphoenix
Super Member
:thmbsp:
perchdog
AudioDouchebag
Tmad, first of all bravo for such a complete write-up... It is very informative and nicely done..
I do have a comment though and has to do with this statement.
Ok this is very true and I have no problem with that. What I do have a problem with is your selection of respriator. The mask that you have shown in your tutorial is meant for dust particulates. To filter out the fumes you need something a little more complicated, a cartridge design with proper cartridge. Also you would be better off doing this part outside or in a garage where there is mucho ventalation. Below is a link for some of the products 3M offers, they are more expensive but do provide the proper protection.
http://solutions.3m.com/wps/portal/...E3E02LES9MG812H2_nid=HCLKF8CQL5beF3RH7CD92Ngl
I do have a comment though and has to do with this statement.
Ok this is very true and I have no problem with that. What I do have a problem with is your selection of respriator. The mask that you have shown in your tutorial is meant for dust particulates. To filter out the fumes you need something a little more complicated, a cartridge design with proper cartridge. Also you would be better off doing this part outside or in a garage where there is mucho ventalation. Below is a link for some of the products 3M offers, they are more expensive but do provide the proper protection.
http://solutions.3m.com/wps/portal/...E3E02LES9MG812H2_nid=HCLKF8CQL5beF3RH7CD92Ngl
skydog2112
skydog2112
Good stuff
Wow,this is great stuff,thanks to all.I will need all of this on my project.thx again.
Wow,this is great stuff,thanks to all.I will need all of this on my project.thx again.
shacky
Addicted Member
Excellent Write Up. Will do a lot to keep these gems in circulation.
As Roy noted that Permatex application is way too heavy and likely changed the F value permanently. It is better to do nothing than over treat the cloth surrounds. Wouldn't want to see anyone do that to AR 3 or 3a woofers
I used rubber cement on first pair of 2AX's and Alene's on KLH 6's all from suggestions here. In hind sight I wish I hadn't.
But other than that you have done AK proud! :yes:
As Roy noted that Permatex application is way too heavy and likely changed the F value permanently. It is better to do nothing than over treat the cloth surrounds. Wouldn't want to see anyone do that to AR 3 or 3a woofers
I used rubber cement on first pair of 2AX's and Alene's on KLH 6's all from suggestions here. In hind sight I wish I hadn't.
But other than that you have done AK proud! :yes:
Great tutorial! I have 2 pair of AR4x's. You've inspired me to restore 2 of the 4 speakers.
One pair was given to me by a friend who had them given to him by his father many years ago and they lived in a closet until he gave me them a couple of years ago. I was stunned to find that the pair he gave me both work well except (of course) the Pots and the woofer surrounds are leaky. I will clean them, probably replace the caps and seal the woofers. The cabinets are in pretty remarkable condition, so it'll be fairly easy to bring them back. These 2 will be my babies, likely paired with my Altec 714 Receiver, Teac A6010 and Dual 1218 TT. Should be a 70's match made in Heaven.
As for the other pair, quite a completely different situation, got them at a garage sale in the rain for $5, one is complete and original but in bad shape, the other has been "fixed" by a hack that didn't know jack about them for real. No problem. As it turns out both tweets are separated from their frames and only one has the original woofer. The cabinets are pretty rough, maybe some sanding and a little patch work + finishing can make them respectable looking again. As for the drivers, I now have a spare woof and xover parts for the good pair and I also have the chance to do a Zilchification! He had several iterations that caught my attention long ago, here: http://www.audiokarma.org/forums/showthread.php?p=2372603#post2372603
The original pictures of my thoughts for the AR4x's related to that post are here:
I used an Altec 604-8K xover to get an idea of the sound and liked it very much! :thmbsp:
One pair was given to me by a friend who had them given to him by his father many years ago and they lived in a closet until he gave me them a couple of years ago. I was stunned to find that the pair he gave me both work well except (of course) the Pots and the woofer surrounds are leaky. I will clean them, probably replace the caps and seal the woofers. The cabinets are in pretty remarkable condition, so it'll be fairly easy to bring them back. These 2 will be my babies, likely paired with my Altec 714 Receiver, Teac A6010 and Dual 1218 TT. Should be a 70's match made in Heaven.
As for the other pair, quite a completely different situation, got them at a garage sale in the rain for $5, one is complete and original but in bad shape, the other has been "fixed" by a hack that didn't know jack about them for real. No problem. As it turns out both tweets are separated from their frames and only one has the original woofer. The cabinets are pretty rough, maybe some sanding and a little patch work + finishing can make them respectable looking again. As for the drivers, I now have a spare woof and xover parts for the good pair and I also have the chance to do a Zilchification! He had several iterations that caught my attention long ago, here: http://www.audiokarma.org/forums/showthread.php?p=2372603#post2372603
The original pictures of my thoughts for the AR4x's related to that post are here:
I used an Altec 604-8K xover to get an idea of the sound and liked it very much! :thmbsp:
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Turdherder
New Member
Thanks for the tutorial, I picked up a pair of 4x at a garage sale this weekend. The seller wanted $10 for the pair but when he took them off the shelf the grille fell off one and the screws were halfway out of the woofer. He told me to just take them and forget the 10 bucks. I tried the whole one last night and it sounded great! Looking forward to tinkering with the bad one.
Turdherder
New Member
I need a bit of help. There was a tag on the bad speaker cab that said "x over" and the wires to the tweeter had been desoldered. I held the wires on the terminals and got nothing, rotated the pot many times, still nothing. Went direct from amp to tweet (briefly) and got sound. Removed the pot and disassembled and it looks really good, nice shiny coil, no corrosion at all. The woofer seems to work fine.
I'd appreciate any tips to confirm that the pot is OK and any (easy) method to determine if the crossover is, in fact, the culprit as noted on the tag. I've read a dozen troubleshooting/ resto threads here on the 4x and most of them hit on the capacitor briefly, then veer off to the pots. To you pros a re-cap appears to be a no-brainer but I don't have a clue on how to replace my cap (and coil?) on the 4x. Any help is appreciated, I'd like to try to get this thing working instead of parting it.
I'd appreciate any tips to confirm that the pot is OK and any (easy) method to determine if the crossover is, in fact, the culprit as noted on the tag. I've read a dozen troubleshooting/ resto threads here on the 4x and most of them hit on the capacitor briefly, then veer off to the pots. To you pros a re-cap appears to be a no-brainer but I don't have a clue on how to replace my cap (and coil?) on the 4x. Any help is appreciated, I'd like to try to get this thing working instead of parting it.
tmad40blue
"I can hear forever!"
Buy a new Dayton-brand capacitor of the same value from parts-express.com. Use the soldering tips in this tutorial to unsolder the old capacitor and solder the new one in. Might as well order two and replace the other one while you're at it.
If that doesn't do it, clean the pots anyway. They could be the culprit.
Then check every wire that leads to the tweeter, starting from the terminal plate on the back.
If that doesn't do it, clean the pots anyway. They could be the culprit.
Then check every wire that leads to the tweeter, starting from the terminal plate on the back.
Turdherder
New Member
One 20uF cap per speaker? Drill the rivets out of the mounting strap for the old capacitor and toss the cap & inductor?
tmad40blue
"I can hear forever!"
Don't touch the inductor. It's fine.
Leave the old capacitor in there, cut the wires going to it, and solder your new capacitor into the circuit. Done.
Leave the old capacitor in there, cut the wires going to it, and solder your new capacitor into the circuit. Done.
As Roy noted that Permatex application is way too heavy and likely changed the F value permanently. It is better to do nothing than over treat the cloth surrounds. Wouldn't want to see anyone do that to AR 3 or 3a woofers
! :yes:
What about something like bookbinding glue ?
http://www.amazon.com/Neutral-PVA-Bookbinders-Adhesive-Bottle/dp/B0025TZ26Q
tube-a-lou
Addicted Member
Hi,
Great threat on restoring the AR speakers, Bet they sound terrific!
Tube
Great threat on restoring the AR speakers, Bet they sound terrific!
Tube
tmad40blue
"I can hear forever!"
Glad you're finding it helpful. Would it be possible to maybe send me your PDF to my email (tmad40blue at gmail dot com)? I would love to have a "download this guide as a PDF" link in the original post.
maddog37
Super Member
I just wanted to thank tmad40blue for the excellent tutorial on cleaning up AR-4Xs. And yes, I sent him a PM with my thanks also. They have been tested and are functional, but not finished yet. I'm still thinking about a recap.
But there are differences between the two speakers, and I'm wondering what's the story behind that. I didn't notice anything internal that indicated any modifications or repairs.
One woofer has the ribbed cone, while the other is a stiff cardboard -- any thoughts? Any it feels that the one with the ribbed woofer is actually heavier, with fiberboard as opposed to plywood.
Also the tweeter edge on one is loose, any specifics on what to use to secure it better?
The SNs are quite different, so maybe that's why?
But there are differences between the two speakers, and I'm wondering what's the story behind that. I didn't notice anything internal that indicated any modifications or repairs.
One woofer has the ribbed cone, while the other is a stiff cardboard -- any thoughts? Any it feels that the one with the ribbed woofer is actually heavier, with fiberboard as opposed to plywood.
Also the tweeter edge on one is loose, any specifics on what to use to secure it better?
The SNs are quite different, so maybe that's why?
Attachments
There a were a number of different woofers used in the 4x. Some 4x's were not true "acoustic suspension" designs, and allowed for some leakage through the dust cap and surround....so slight response differences do exist.
Since this thread was started it should be noted that the application of such things as Permatex gasket sealant to 4x surrounds has been found not to be advisable.
Roy