Giorgio AR Posted March 16, 2019 Report Share Posted March 16, 2019 I also hope to receive help and valuable advice from CLS members on my project to build a "new" AR-3st. I have a very good pair of tweeters around '75 year, purchased as spare parts in surplus, currently not used. My idea is to recreate a new supertweeter (as done in the 60s by AR), with the difference of using the .75 "tweeter instead of the original phenolic dome tweeter. The tweeters are visible in the first three photos, the next two photos show the canvas I will use on the speaker, donated by a grill of my Heathkit AS-2a (it is practically the same as the original AR, also compared to the photo below that show the original AR-3st). The remaining photos show the original supertweeter and the vintage brochure (although the mounted tweeter will be different from the original design, I think the new AR-3st will look almost indistinguishable from the original). The biggest problem for me is finding the value of the coil to cut the frequency, the measurements of the cabinet are easily detectable knowing the length of 11 1/2 "published on the brochure (if there is a member who is in possession of additional measurements or technical data it's welcome !! Thanks Giorgio. Quote Link to comment Share on other sites More sharing options...
genek Posted March 16, 2019 Report Share Posted March 16, 2019 Just take the values from the schematics for the 3a. The 3t and 3st were designed to duplicate the crossovers from the 3. Quote Link to comment Share on other sites More sharing options...
Giorgio AR Posted March 16, 2019 Author Report Share Posted March 16, 2019 Thanks Genek, but I still need some help: the value of the coil (I don't have the ability to understand which coil to use), and how to connect the capacitor that seems to double from the photo (it should provide the tweeter cut and set the rest of the frequency directed the AR2 or AR1?). If I can understand what components to use and their connections, the work to replicate the AR-3st will be less difficult for me, I have good manual skills Quote Link to comment Share on other sites More sharing options...
Aadams Posted March 16, 2019 Report Share Posted March 16, 2019 Giorgio The AR1W has a capacitor that limits the woofer to around 600hz and below. I believe an AR5 schematic may have the info you need. Just a guess. Quote Link to comment Share on other sites More sharing options...
Giorgio AR Posted March 16, 2019 Author Report Share Posted March 16, 2019 Thanks, I will try to understand the AR5 scheme, welcome further technical help on how to successfully filter correctly the supertweeter,I think that the frequency cut must be at the tweeter (for example from 7000 hz upwards) and at the other speakers (from 7000 hz downwards). Not being a technician, this for me is a big obstacle, the same problem to be able to give a cut of frequency also to the 1MS that I now use connected to AR2 !. Thank you Aadams Giorgio Quote Link to comment Share on other sites More sharing options...
Aadams Posted March 16, 2019 Report Share Posted March 16, 2019 moved Quote Link to comment Share on other sites More sharing options...
script56 Posted February 11 Report Share Posted February 11 I am missing bolt that holds the coil onto back of cabinet. Does anyone have spare? It may be used in other ar products besides the ar3-st. It is screw with riveted flat back. Circled in red in attached pic. Quote Link to comment Share on other sites More sharing options...
RoyC Posted February 22 Report Share Posted February 22 On 2/11/2024 at 7:52 AM, script56 said: I am missing bolt that holds the coil onto back of cabinet. Does anyone have spare? It may be used in other ar products besides the ar3-st. It is screw with riveted flat back. Circled in red in attached pic. If you haven't already done so, remove the clip and tap the rivet/shaft out from the inside. You can easily replace it with a brass or stainless steel screw, nut, and washer to replace the entire spring clip arrangement. (Use brass or stainless hardware because it is non-magnetic.) Quote Link to comment Share on other sites More sharing options...
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