Carlspeak Posted January 20, 2012 Report Share Posted January 20, 2012 Check out the post at the link below. It contains recent test data on AR3a vintage 150 and 50 uF Compulytic capacitors and compares it with fresh, new ERSE caps of the same uF values. The Compulytic caps performed equally as well despite there age. There's something to be said about good American made Sprague products!http://www.classicspeakerpages.net/IP.Board/index.php?showtopic=6354&view=findpost&p=90734 Link to comment Share on other sites More sharing options...
HarryM Posted January 22, 2012 Report Share Posted January 22, 2012 Thats good to know.Would the smaller compulytic caps be the same because I'm hopeing the 10uf caps in my AR-8 are bad LOL.Maybe if you have time you could explain for me and others that don't know,what is the difference between caps.As in compulytic,nonpoler,bipoler and all the other ones I've come across that I don't know the names of.And if it has a compulytic cap do you need to use a compulytic cap or can you just use a nonpolar cap.The guy where I get my caps from recommended nonpolar for speakers.This info would help me out alot.I'd also feel alot smarter. Thanks,Harry. Link to comment Share on other sites More sharing options...
Carlspeak Posted January 22, 2012 Author Report Share Posted January 22, 2012 I haven't tested that cap, but feel from what I have tested that you 10 uF should be fine. Link to comment Share on other sites More sharing options...
HarryM Posted January 23, 2012 Report Share Posted January 23, 2012 Thanks,I'm running the AR-8's right now and I think it may have been leaky cabs. Link to comment Share on other sites More sharing options...
Carlspeak Posted January 23, 2012 Author Report Share Posted January 23, 2012 If the cab was leaky, that would have affected the bass response. The 10 uF cap you asked about should be in the tweeter circuit and thus have no effect on bass.With regard to your 1st question about different caps, I can answer by saying the Compulytics are non-polar electrolytics (i.e. NPE's). Bipolar is the same thing and just a different name for the NPE's. If you do change speaker crossover caps, always get NPE's or film caps because the electrical signal to speakers is comprised of alternating current, thus necessitating a bi-polar capacitor. Whereas, uni-polar caps are for DC circuits; generally upstream withing amps and pre-amps. BTW, Sprague NPE compulytic caps are no longer available.The more modern and also more expensive film caps are all no-polar. Their dielectric is synthetic film instead of the chemical paste used in electrolytics.BTW2, thanks for your interest. I was beginning to wonder if anyone was interested in this thread! Link to comment Share on other sites More sharing options...
HarryM Posted January 24, 2012 Report Share Posted January 24, 2012 Thanks for the response.I am interested in anything related to speakers and xovers.It's pretty easy to change caps but I don't really know what they do in a xover,same with resistors and the coils of wire.Ì`ll give you an example.Today I was playing with the paisley's. I had changed out the woofers because only one worked but they are cheap power hungry woofers and they ruined the clean clear sound that I had.So I thought I'll try fixing it by putting a resistor across the terminals on the woofer.The xover on the paisley seems very complex for a 2way speaker so I didn't want to touch anything on it.So I put a 5ohm 10 watt on one speaker and hooked them up and thought it's ok but not right so I put 3ohm 10 watt on the other speaker to compare the 2 and the speaker was very quiet and when I turned it up the tweeter started poping and I concluded that I should take the resistors off of both and leave them alone until I have an Idea of what I`m doing.LOL.I`ve learned alot from you and others on this site but usually I just read and not reply as I think alot of others do.I`ve gone over all the AR pages reading any thread that I think might be interesting.So keep posting and I will keep reading. Thanks,Harry. Link to comment Share on other sites More sharing options...
rrcrain Posted January 24, 2012 Report Share Posted January 24, 2012 Here's an interesting article regarding old electrolytics.http://www.nmr.mgh.harvard.edu/~reese/electrolytics/ Link to comment Share on other sites More sharing options...
Carlspeak Posted January 24, 2012 Author Report Share Posted January 24, 2012 That looks like fun stuff for an electronics hobbyist. OTOH, NPE's are SO cheap to replace, I don't see the point for most of us speaker guys who are anxious to get their speakers up and running to their best ability. Link to comment Share on other sites More sharing options...
HarryM Posted January 24, 2012 Report Share Posted January 24, 2012 Lots of usefully info there but it's alittle beyond me at this time.I did save it for future reading. I now have a better understanding of what a 'variac'(spelling) is.I knew it was for introducing power slowly so you don't blow things up but I didn't know you could use it to rebuild caps.Thats interesting.Thanks rrcrain.I think this is very useable for stereo equipment but I agree with Carl about speakers.I get caps for .75 each if I buy 20 or more of them and they don't have to be the same. Repairing stereo equipment is something I would like to learn about.I'm one of those guys that wants what I have to work and if it doesn't I want to beable to fix it. Link to comment Share on other sites More sharing options...
rrcrain Posted January 25, 2012 Report Share Posted January 25, 2012 Carl,I vaguely remember reading "somewhere", where ever that somewhere was, that many of the really old electrolytics contain PCB's. They have an incredibly long life, but do we want these capacitors inside our home if this is true?Richard Link to comment Share on other sites More sharing options...
Carlspeak Posted January 25, 2012 Author Report Share Posted January 25, 2012 Here's some information that may help.http://www.ct.gov/dep/cwp/view.asp?a=2710&depNav_GID=1638&q=324258IIRC, some really early AR speakers had these strange looking caps that were comprised of a group of small, silver metal containers tied together with wires interconnecting them. They may be of the type you refer to (i.e. oil filled). What I don't know is if they also contained PCB's. Link to comment Share on other sites More sharing options...
genek Posted January 25, 2012 Report Share Posted January 25, 2012 Prior to the 1970's, PCBs were used just about everywhere. They were banned in the US in 1979, and since that time any fluid-filled electronic device that does not contain them is required to marked as pcb-free and all unmarked units are supposed to ba assumed to contain them and handled and disposed of as if they do. Link to comment Share on other sites More sharing options...
Carlspeak Posted January 25, 2012 Author Report Share Posted January 25, 2012 I had saved a hard copy of this thread that dates back to 2004. It was written by one of the authors of the AR3a restoration document, johnieo."Early Capacitor Manufacturing History".... Interesting reading. However, I couldn't find any mention of the Sprague Compulytic caps. John O'Hanlon does discuss oil filled caps though. His description matches my recollection of those strange, bundled silver can caps in very early AR's.Enjoy the read!http://www.classicspeakerpages.net/IP.Board/index.php?showtopic=981&hl=early&fromsearch=1 Link to comment Share on other sites More sharing options...
HarryM Posted January 26, 2012 Report Share Posted January 26, 2012 I can't add much to this other then,I didn't change the caps on the AR-8's as per Carl's advice and on listening to them I can't hear anything that tells me they don't sound right.They are,to me,a medium to high volume speaker and are not great for lower volume listen.On the other hand the AR-28s's went from being a nasty sounding speaker to a good sounding speaker after a recap and really helps the AR-8's out at lower listen levels.I switch them off for any medium to high volume listening.I also noticed the caps in the AR-28s's were smaller made in Japan caps.I think the 28s's are also the newest AR's that I have. Link to comment Share on other sites More sharing options...
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