oldarnut Posted July 3, 2015 Report Share Posted July 3, 2015 I have four AR3a's and two AR3's. I also have a pair of ARLSTII's that someone replaced the tweeters--each has an original AR tweeter, one Yamaha, and one KEF tweeter.Is there a Vifa or other brand tweeter that will work with my AR3a's without electrical mods?Is there a Vifa or other brand tweeter that will work with my AR3's without electrical mods?Is there a Vifa or other brand tweeter that will work with my ARLSTII's without electrical mods?I have one functioning pair of AR3a tweeters, but their output is very low. The AR tweeters (one in each) in my LSTII's seem to be OK. My AR3's have some old Radio Shack tweeters in them.On another subject, I've cleaned the rheostats with #320 emery cloth, Scotchbrite, spray contact cleaner, and once with WD40--all with poor results. The pots work OK for a few days and then become very intermittent. Why is this such a trouble spot with our old AR's? Link to comment Share on other sites More sharing options...
genek Posted July 3, 2015 Report Share Posted July 3, 2015 There is no new tweeter that will produce the right response without some kind of crossover mod. The addition of one single inductor with the HiVi unit is the closest thing to nothing we know of.Once the old pots have been cleaned, the corrosion process resumes almost immediately. They should be potted in a dielectric grease to keep air off the bare metal windings and wipers. Link to comment Share on other sites More sharing options...
oldarnut Posted July 7, 2015 Author Report Share Posted July 7, 2015 Do you mean the pot windings and wiper should be coated with dielectric grease after cleaning? I don't understand what "potted" means regarding the potentiometers.Regarding the inductor in parallel with the HiVi tweeter for the AR3a---that would lower the output of lower frequencies that get to the tweeter voice coil, which would effectively raise the crossover point. Is that correct? What audible effect does not adding that inductor have?I'm guessing the tweeter substitution for the AR3 would be quite different, since the crossover is different from the AR3a. Link to comment Share on other sites More sharing options...
genek Posted July 10, 2015 Report Share Posted July 10, 2015 Yes, "potting" is the term for enshrouding a component in something that cuts them off from contact with air or insulates them.People who have used the HiVi tweeters without the inductor have described the HFs as "harsh." I haven't tried it myself, so I can't describe it for you.There were four different versions of the AR-3 crossover during the life of the model, so my guess is there's a pretty good chance that you're right about at least one of them needing a different crossover mod. Link to comment Share on other sites More sharing options...
Turbon Posted July 13, 2015 Report Share Posted July 13, 2015 "I'm guessing the tweeter substitution for the AR3 would be quite different, since the crossover is different from the AR3a" Touche! The AR3a is mapped territory but I'm another one searcing an answer on this. "On another subject, I've cleaned the rheostats with #320 emery cloth, Scotchbrite, spray contact cleaner, and once with WD40--all with poor results. The pots work OK for a few days and then become very intermittent. Why is this such a trouble spot with our old AR's?" Dielectric grease have been mentioned, any brands one could search for that has been used with success? Maybe bend the collector to increase the pressure against the wires? Be very carefull though! I'm not there yet but that is one thing on my mind to test if they won't work. Regards Link to comment Share on other sites More sharing options...
stupidhead Posted July 13, 2015 Report Share Posted July 13, 2015 Hello oldarnut. Some pics of your pot(s) would be very helpful in answering your question about restoring them (if possible). Link to comment Share on other sites More sharing options...
genek Posted July 13, 2015 Report Share Posted July 13, 2015 I used DeoxIT L260, a lithium-based grease by Caig in my AR-3a rebuild. I chose this particular one mostly because the manufacturer was in the next town from where I was living at the time and they sold it in little 2g tubes so I wouldn't have a tub of the stuff left over after potting four controls. But any particle-free lithium grease will work as well. Link to comment Share on other sites More sharing options...
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