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heck JL, If I break down and buy me sum good caps from Bob Crites or DeanG, it will be getting into my Boiled Peanut Money ! You lucky Scoundrel, get you a deal on that ESR Meter, I am soo jealous. I never really checked Parts X Press before, but them Dayton 1 percenters look cool ? I bet old man Crites and DeanG both match crossover caps ? I even have a pic of Bob in my mind, measuring Caps, in between bites of Arkansas Catfish ? IF the Madisound Surplus Poly's do not work out, it will be no big deal, 2 of the 10uf's, in stacks of 3 to make 30uf are simply woofer dump caps. One is the lower midrange horn crossover, so it IS a very important Cap. Oh, I did call Madisound, found out the Caps are only 4 to 5 years old !! So, 3 of them in parallel should be ultra low ESR ... If they do not sound good, and assuming the Solens I ordered for the top of the midrange crossover, and bottom of the tweeter do, I will simply grab a couple more 30uf Solens for the midrange high pass. ERSE has some good prices on Poly Caps, as do Madisound and Parts Express. What Caps are you gonna try JL ?

Good thread, thanks ! Wish I had one of dem meters !!!

Great thread! Of course, this all assumes low ESR is always desirable, and it is not. Not always. Go to classicspeakerpages.com and read what Ken Kantor has to say about Low Esr Caps.Often, the ESR of the original cap was taken into account in the crossover design. Replace it with a low ESR Cap, you change the crossover. You may, or may not like this change, depends. I just recapped my E/V Sentry III's with OEM type caps, did not like it, so I am trying some Low ESR Solens and Paralleld older Poly caps, just for a change of pace. I wish I had me one of them meters !!!

Well, since we hear a balance of direct vs reflected sound anyway, who cares ? Good Sound is what it is all about anyway, not pleasing a scope, right ? Why not do Impulse Response testing instead AL ? The Danish believe the the tweeters that pulse test the best, sound the best ?

We shall see, maybe Madisound has some equipment to check ESR ? I can not imagine them selling a bad capacitor, they have way too much to loose. Their market is hobbyists, and speaker modifiers. If word got out they were selling bad capacitors, that could be like a restaurant known for food posioning !!! I am actually thinking just the opposite. The company who made these surplus caps has only been making caps since 1998, thats only 12 years, if these are that old ? Heck, how do you know when you buy a Solen or an Auricap or a Mundorf it is "brand new' ? That sucker may have sat for 10 years ? Bob Crites sells Sonicaps. I dont remember them 10 years ago , so they are most likely a newer capacitor design ? Regardless, I could actually see Bob checking each cap for ESR before it leaves his place. He's got him a fancy ESR Checker.

Yes, I need 30uf, not 20. The E/V Sentrys use the same brand of caps for both sections of the woofer to mid crossover, so I kind of wanted to keep that the same. Bob Crites told me that in a woofer dump cap, I could use electrolytic, since all they do is roll the woofer off. But a 60 cents a cap, I thought I would go all poly. I have no idea what the ESR of these surplus poly caps may be, but it can't be as high as the 36 year old Mylars that came stock in here, and are still working fine.

For My Electro Voice Sentry III Crossover Rebuild, I need the following caps 3 - 30uf 1 - 17.7uf and 1 - 2uf - times 2 of course for the pair of speakers. Two of the 3 - 30uf caps roll off the woofer, and one keeps lows out of the horn midrange, the stock caps were all the same brand, and 36 years old. The 17.2uf cap rolls off the midrange horn , and the 2uf cap is on the tweeters (ST 350) Madisound has these 10UF Poly Caps on sale for 60 cents each. They are sold as surplus caps. The company TYEE is out of Fullerton California, and has been in business since 1998, so at the very most, the caps are 12 years old, maybe less ? They are NOS I plan to take 3 of these 10 UF and combine them to make up one 30uf cap. This will give me the 30uf I need, and even lower ESR then one 30uf cap (resistance in paralell) For the 17.7 and the 2uf Caps, I ordered Solens, and a surplus 2uf Mylar from Madisound, just to have something else to roll. Unfortunately, all the Motor Run Caps I ordered will not fit! So I was going to give this a try. Anyone ever used these Madisound Surplus Poly Caps before ? And what do you think of using a bunch of caps to make the desired capacitance vs one cap ? I plan to soak them in Coconut Milk overnight, for a sweeter sound ! Seriously, 30UF Poly Caps are not cheap, and I need a total of 6 of them for my pair of speakers, At 20 bucks a shot, thats 120.00 ! Comments ?

Ok, on what side of capacitor ?

I wonder what wattage this resistor must be ?

No measuring equipm,ent Mike, but your idea sounds good. what side of cap does resistor go on ?

Hey Maron, did I ever tell you I picked up some Tannoy's ? Yep, a pair of Tannoy D 50's, the 8 inch dual concentric in a small floor standing cabinet. Musical little bastards they sure are, imaging fools too. Their crossovers are "safe" from me, encased in Epoxy. Quite fond of them I am, no real bass in my 24 by 20 foot room, but there is just "something about" the dual concentric driver. I can see why people are fond of these, can only imagine what the big brothers to these must sound like ?

First, Happy Birthday again AL ! I threw the old caps back in, all except for the 36 year old Paktron 2uf Mylar Tweeter cap. I had a new ERSE 2uf Mylar in there, I probably should have left it. With all the old caps back in the Sentry III's, the sound is warm and almost romantic compared to the new Mylar and High Quality ERSE Electrolytics that were in there. I was forced to go to Radio Shack to get a 2.2uf Non Polar Electrolytic, since the old tweeter cap is no longer usable.I wanted a high esr tweeter cap, to duplicate the ESR of the 36 yerar old mylar tweeter cap as close as possible. THIS cap must go! It has almost muffled the ST 350 tweeters! it took the sheen off of cymbals, and the bite out of Trumpets. It is a 2.2 vs the called for 2.0 UF, and a 20 percent vs a 5 percent cap as well. God only knows what it's value is, and it's ESR must be sky high, since it has muffled the tweeters. We measured every one of the 36 year old caps, and they are right on the money, as far as capacitance, ESR is unknown, suspect it may be high. The speakers seem to "want this" AL. I think if I just play with the 2uf tweeter cap, I may be done ? It seems a shame to have all these motor run caps I ordered not get used, but they are a SOB to mount, and make room for. I fear they may be more of the same sound as the ERSE Mylars. Yes, with the new caps, the speakers were more detailed, but they were also far brighter too. Not bright like many Klipsch Speakers, but just a tad too "in your face' for my tastes. IS it possible AL, that over a 36 year period the drivers themselves may have changed a little, and the speakers want these high ESR caps ? As a fellow ham, you are aware we can computer model a Yagi Antenna, and it will yield good performance. But there is no subsitute for tuning an antenna in place. The computer modeling programs are great, they just can't account for every variable. Perhaps the old caps are compensating for my equipment, or room, or perhaps my ears ? Since I put the old caps back in, I love the E/V Sentry III's again, except the performance of the tweeters is crippled by the Radio Shack Electrolytic. I think I will just try a bunch of 2uf tweeter caps, till I get my sound ? The old Paktron 2uf Mylars may be re usable, but my eyes are not so good to re solder leads to them again. I clipped em too short. I am driving my girlfriend crazy, she is bitching all I do is fool with speakers, or on computer. I told her "Honey, I am almost 56, sorry if women are not the priority for me they once were' I offered to buy her a plane ticket back home ! Good Lord, they complain if you are out fishing or hunting, or out in a bar, but when you are home, they complain too ! I just dont understand Women, do they not realize how important it is for us men to have good sound? Geez

Very Interesting ..... I changed the 36 year old caps all out in my E/V Sentry III's, actually twice, with not good results! Tried several different combo's of new Mylar and electrolytic caps, can't seem to duplicat the magic they once had. So, I have replaced one speaker with all it's old caps Except the 2 uf old mylar on the tweeters, I clipped the leads too short on the old cap, unable to repai it. I listened, seems like the magic is returning. I will go back out there and re do the other speaker. Since the old tweeter caps are unusable, I went to rat shack and got some 2.2 u NPE Caps 20% caps. I figured thes will have ESR perhaps approaching the old 2uf Mylars? They will have to do, for now.I also have enough Motor Run Caps to re do my speakers, but installing them will be a *****. This is my project for the day Mike. I know in theory, it is bad to use old high ESR caps, and an electrolytic on the ST 350 tweeters in the Sentry III's. But I must trust my ears. Let me go re do the second speaker, and we will see where I am at, as far as sound goes ? I wish I had a crossover schematic for the sentry 3's, it crosses at 600 and 3.5 k, and one slope is 18 db, it uses 3 - 30uf caps, one 17.5 and 1 - 2uf on the tweeter 2 of the 30uf caps are in parallel, be back in a few

Thanks Mike, will it shift UP or DOWN in crossover frequency

Ok, lets say we have a 30 year old Mylar Cap that still measures it's rated Capacitance. Now, lets just assume it has high ESR, say from .5 up to maybe 1 ohm ? What does this do to a crossover ? does it shift the crossover frequency UP or Down, does it mess with the slope ?

Happy Birthday OM 73

Well Paul, my motor run caps arrived last week. I ordered all oval caps, but got 2 17.5 uf round ones! I complained, and they sent me out 2 replacements. The replacements are HUGE oval Aerovox Caps, and I do mean HUGE. They dwarf the 30uf Caps! Went down to Lowes, got some plastic conduit clamps touse to secure the monsters to the E/V Sentry III crossover board. I still have the Aerovox 17.5 Round Caps, so maybe I will experiment ? The 2uf Tweeter caps are GE Aluminums,and the 3 30uf Caps in each Sentry III crossover are Ronkens. I wish I had a schematic for the Sentry III crossover. It uses 3 30uf caps, wonder what ones are woofer roll off,and what one is midrange high pass ? It uses 2 of them in parallel on one circuit, and a single 30uf on another. I would assume the two 30uf's are woofer dump caps ? I have 2 brand new high quality ERSE electrolytics in there right now, like to leave them in, it will be a lot easier then mounting 2 of these huge motor runs. Oh, the 3 - 30uf motor runs all have resistors soldered across the terminals, unlike the other caps I bought. I was told to just clip the resistors. I did shake the caps, and listen for Oil sloshing around, and the huge 17.5 uf Aerovox Caps sound like a millk shake !!! Lots of slushing going on !!! If indeed the 2 30uf Caps are in the woofer circuit of the Sentry 3's, then the remaining 30uf Cap must be for the bottom of the midrange crossover,and the 17.5 for the midrange roll off. But w/o a crossover schematic, I can only guess. Crossover points in the E/V Sentry 3 are at 600 and 3.5k.

My Cornwall 2's "came stock" with Crites Titanium Diapraghms in the Tweeters []

There was a distraught homeless man Al - standing at a busy Tampa intersection. He was flying a sign that said "Homeless - Will Work For ALK Crossover" As the mental health professionals attempted to keep him from running out into traffic, he kept screaming " I need an ALK Crossover" over and over again. One Policeman assured him that his Klipsch Speakers sounded just fine w/o any ALK Crossover. This was not working, and so the authorities even got Roy Delgado of Klipsch on the phone ! It is said Roy even faxed down polar plots to show the mentally ill man there was no need for an ALK Crossover. Finally, the authorities left the confused but harmless Man alone with his delusion.

LOL

The 30 UF Caps I bought (6 of them) for the sentry III crossover have resistors across them. I will simply cut the resistors. I am unfamiliar with motor start and run caps. It was said that a resistor across the cap is a start, not a run cap. I called the place I bought from, they said to simply remove the resistor. Unlike a start cap, they are not a UF range type cap, only marked 30 UF. One would think resistor only there for excess voltage maybe ? I will worry about how to permanent mount only if they sound good ? I think I can manage some kind of mount, if only plastic ties. The E/V crossover has tons of room, thank God ! BTW Dean, that was very nice of you in another thread, to offer to fix a problem for a forum poster, for onoly the shipping costs !

If you LOOk Dean, I have been a forum user for a long time, and have never needed your golden screwdriver services. You aint breaking my heart .....

If it has resistor across the cap, I believe that is a motor start cap, which you don't want to use for audio. When I bought some of the GE motor runs for my center crossover from him, Bob sold me some nice brackets. He may still have some. Well, I ordered RUN, not start Caps! I shall have to call the place in Nebraska and tell them, plus, I got 3 different BRANDS of Caps from them, when the pics they displayed all showed the same kind! I have been busy with income taxes, I will call today!

That is very kind of you Dean !

Thats Pretty Bob, and very professiional. I got 3 different brands of caps, 2 oval, one round, when I ordered all oval! some are Ronken, some are Aerovox, and some are old GE.The 30 UF are Ronken, 17.5 UF are Aerovox and 2UF are GE I may look into some plastic tie downs maybe ? I will probably see how they sound first. The 6 -30uf ones have a resistor in between the terminals ??