ironlake Posted September 5, 2012 Report Share Posted September 5, 2012 was it determined if the metal capacitor in the 4x held its value better than the wax one? I know when in electronics school we had a lot of old caps around in metal cans that easily came within 10% of rated value but most of these came out of ex military stuff. I know I built a massive power supply for my car stereo with a group of them and they sure worked good. that military stuff was ww2 and I went to school in the 80s so it was old stuff. Link to comment Share on other sites More sharing options...
ra.ra Posted September 5, 2012 Report Share Posted September 5, 2012 It has been pretty well documented that the wax blocks from Chicago (Industrial Condenser) have most probably lost their mo-jo, but my recent question about the silver can Sprague compulytics elicited no response. Even high quality 20 mf caps are not that expen$ive, so I plan to replace mine unless I am convinced otherwise. Link to comment Share on other sites More sharing options...
RoyC Posted September 5, 2012 Report Share Posted September 5, 2012 We conducted extensive testing of various AR and non-AR capacitors when we were putting togther the AR-3a Restoration guide. Forum member Carl has also done much testing. The majority of the large metal can Sprague ("Compulytic") caps tested very well in these tests. ALL others, including the metal Industrial Condenser ("Royalytic") can caps, did not measure well.If you guys intend to continue in this activity, an LCR meter should be on your shopping list. If not, my advice is to replace the caps in every old speaker you intend to restore.Roy Link to comment Share on other sites More sharing options...
ra.ra Posted September 7, 2012 Report Share Posted September 7, 2012 Thanks, Roy, for this confirmation on the Compulytics. I do own an LCR meter, but for whatever reason (operator ineptitude, perhaps?), I have never been able to register capacitance measurements with it."If it ain't broke, don't fix it" is often a sensible and appropriate rule-of-thumb, and as much as I may dislike the idea of replacing potentially good components - - - in this case, old can-type capacitors - - - if I am unable to measure and confirm their values, it doesn't hurt too much to invest ten or twenty dollars for a pair of new caps in order to restore a pair of 40 year-old speakers, and therefore, your advice is consistent with my thoughts on this. Link to comment Share on other sites More sharing options...
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