gary_wong5 Posted July 7, 2011 Report Share Posted July 7, 2011 I have recently acquired a good looking pair of walnut AR3 speakers. The high range tweeters are dead quiet even when turning the pots. One of the woofer has clicking sound, the mid-range pot of this speaker is rather loose as compared to other pots. Plan to restore them during this weekend.Anbody here try this pot before? http://cgi.ebay.com.my/ACOUSTIC-RESEARCH-AR-SPEAKER-LEVEL-CONTROL-POT-/160601135186?pt=Speakers_Subwoofers&hash=item256492d852How it sounds compared to cleaned original pot?I shall have more questions to ask in the progress. Hope all of you would advise me in the restoration path. Thank you! Link to comment Share on other sites More sharing options...
JKent Posted July 7, 2011 Report Share Posted July 7, 2011 http://www.parts-exp...tnumber=260-248same thing without the mark-up.Be SURE to read the AR3a restoration guide.http://www.classicsp...-3a_full_pd.pdf Most of what is in there is relevant to the AR3. On page 14 Roy and John discuss the use of L-pads and a resistor to make the sound more "authentic." The L-pads are great.Kent Link to comment Share on other sites More sharing options...
gary_wong5 Posted July 8, 2011 Author Report Share Posted July 8, 2011 Hi Kent, thank you for your input. The pots' are slightly oxidized and cleanable.Please look at attached photo of crossover. Is anyone has the exact circuit diagram? What are the value of capacitors?Thanks a lot.I found this in CSP but not so clear http://www.classicspeakerpages.net/library/acoustic_research/original_models_1954-1974/original_models_schematicss/ar-3_schematics/ar-3_schematic_with_notes.html#previous-photoAnyone has clean drawing and clear recapping advice? Link to comment Share on other sites More sharing options...
JKent Posted July 8, 2011 Report Share Posted July 8, 2011 Hi GaryThat pic is a 3-to-3a upgrade. The original 3 xo is here:http://www.classicsp..._schematic.htmlI started an AR3 restoration that ended up as a 3-to-3a mod. You can see the thread here:http://www.classicsp...?showtopic=6284The AR3 crossover is much simpler than the 3a and IMHO there is virtually no sonic advantage to the more complex xo. AR changed the xo of the 3 a couple of times. Tom Tyson and John O'Hanlon have documented this. Tell us your serial numbers and I'll post the correct xo, but in all versions you will need a 24uF cap and a 6uF cap. If you look at this thread, Post #17 shows my rebuilt AR3 crossover:http://www.classicsp...0432 caps, 2 coils, 2 pots. Simple. That xo has a new inductor added because my 2 speakers had 2 different versions of the crossover. I used Ohmite pots that I had on hand, but I don't think they are worth the trouble and expense. There was a whole thread on how to build a cover that will protect the pots but not decrease cabinet volume significantly. My advice: Go with the L-pads and add a resistor to the mid and tweet (or just the mid if you use Hi-Vi tweets), as described in the restoration manual.Kent Link to comment Share on other sites More sharing options...
gary_wong5 Posted July 16, 2011 Author Report Share Posted July 16, 2011 Hi Kent, thanks for your kind input.Do you think this dirt cheap Permatex Indian Head Gasket Shellac Compound (available at ACE Hardware) also suitable for sealing the woofer's cloth surround?http://www.permatex.com/products/automotive/automotive_gasketing/gasket_sealants/Permatex_Indian_Head_Gasket_Shellac_Compound.htmGary Link to comment Share on other sites More sharing options...
dynaco_dan Posted July 16, 2011 Report Share Posted July 16, 2011 Hi Kent, thanks for your kind input.Do you think this dirt cheap Permatex Indian Head Gasket Shellac Compound (available at ACE Hardware) also suitable for sealing the woofer's cloth surround?http://www.permatex.com/products/automotive/automotive_gasketing/gasket_sealants/Permatex_Indian_Head_Gasket_Shellac_Compound.htmGaryHi thereAbsolutely do not use this compound.Scroll down to gasket sealant and click.Permatex High Tack Gasket Sealant is the one to use. Link to comment Share on other sites More sharing options...
JKent Posted July 16, 2011 Report Share Posted July 16, 2011 Absolutely do not use this compound.Scroll down to gasket sealant and click.Permatex High Tack Gasket Sealant is the one to use.DITTOThe give-away is " Hard setting," You do NOT want a hard set--you want something that will remain flexible.Do the test first: push the woofer cone in and see how long it takes to return. Should take 1.5 to 2 seconds. If it comes back quickly there is an air leak. Check the putty that holds the woofer in place and look for leaks elsewhere. If there are no other leaks then the woofer surround is probably porous. Apply the gasket sealant VERY thin. It may be a good idea to thin it with solvent. Check some of the posts here on that subject. Be very careful not to use too much.Another option is the "WD" white dampening material sold by M_Sound. John (of M_Sound) tells me it is perfect for cloth surrounds.Kent Link to comment Share on other sites More sharing options...
RoyC Posted July 16, 2011 Report Share Posted July 16, 2011 DITTOThe give-away is " Hard setting," You do NOT want a hard set--you want something that will remain flexible.Do the test first: push the woofer cone in and see how long it takes to return. Should take 1.5 to 2 seconds. If it comes back quickly there is an air leak. Check the putty that holds the woofer in place and look for leaks elsewhere. If there are no other leaks then the woofer surround is probably porous. Apply the gasket sealant VERY thin. It may be a good idea to thin it with solvent. Check some of the posts here on that subject. Be very careful not to use too much.Another option is the "WD" white dampening material sold by M_Sound. John (of M_Sound) tells me it is perfect for cloth surrounds.KentKent,If M-Sound's material is like other water based white glue compounds I have measured for this purpose, it will dry too stiffly. I know for a fact he does not have the capability to measure the results. (I tested the Boston FF foam surrounds for him). I'll contact John and have him send me some for measurement and testing. This is NOT something to try without being absolutely sure of the results.Gary, I have developed sealant based on the original formula, which I believe is the best material for the purpose of re-sealing cloth surrounds. Send me a PM and I would be happy to share some with you. It is VERY unlikely, however, that your AR 12 inch woofer surrounds will require re-sealing.Roy Link to comment Share on other sites More sharing options...
JKent Posted July 16, 2011 Report Share Posted July 16, 2011 Kent,If M-Sound's material is like other water based white glue compounds I have measured for this purpose, it will dry too stiffly. Roy, I'm just repeating what John (MSound) told me. Here are his comments:"my white glue is actually a White Dampener… why it's called "WD." Sealing cloth surrounds is EXACTLY what it is For and it NEVER should harden or stiffen! Typically we would thin it a bit, and/or thin it a lot IF we're lucky enough to have access to an air brush which is the best way to apply it to a surround imo (several light coats on both sides). I use it as an adhesive as it will technically NEVER really harden so is impossible to cut an edge of a surround."Kent Link to comment Share on other sites More sharing options...
Carlspeak Posted July 17, 2011 Report Share Posted July 17, 2011 I use slightly diluted white glue to 'dampen' the corrugated (not 1/2 roll) cloth surrounds on pro audio woofers when I finish a recone job. It's normal procedure on just about all except those few that come from the distributor already sealed. These pro-audio cloth surrounds are generally pretty stiff compared to cloth acoustic suspension surrounds. The textile fabric is also much coarser which only adds to it's already inherent stiffness.Keep in mind these pro woofers take a beating in actual use and, IMO, aren't really meant for nuanced home stereo applications. Thus some stiffenening in those pro woofers as the white glue ages will go un-noticed. The testing Roy and I have done with the white glue on vintage AS woofers with fine mesh cloth surrounds has shown they are a different animal from pro audio. Before and after aging tests of resonant frequency has repeatedly confirmed that white glue will raise the Fs significntly as it ages. Link to comment Share on other sites More sharing options...
soundminded Posted July 17, 2011 Report Share Posted July 17, 2011 I use slightly diluted white glue to 'dampen' the corrugated (not 1/2 roll) cloth surrounds on pro audio woofers when I finish a recone job. It's normal procedure on just about all except those few that come from the distributor already sealed. These pro-audio cloth surrounds are generally pretty stiff compared to cloth acoustic suspension surrounds. The textile fabric is also much coarser which only adds to it's already inherent stiffness.Keep in mind these pro woofers take a beating in actual use and, IMO, aren't really meant for nuanced home stereo applications. Thus some stiffenening in those pro woofers as the white glue ages will go un-noticed. The testing Roy and I have done with the white glue on vintage AS woofers with fine mesh cloth surrounds has shown they are a different animal from pro audio. Before and after aging tests of resonant frequency has repeatedly confirmed that white glue will raise the Fs significntly as it ages.What do you think of this?https://www.getflexseal.com/?gclid=CPGL8vbgh6oCFYaD5QodbQ3F0w Link to comment Share on other sites More sharing options...
Carlspeak Posted July 17, 2011 Report Share Posted July 17, 2011 What do you think of this?https://www.getflexseal.com/?gclid=CPGL8vbgh6oCFYaD5QodbQ3F0w I've seen that stuff advertised on TV and wondered about it for surround sealing.I've also read about vehicle body undercoat. Haven't tried it though. Link to comment Share on other sites More sharing options...
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