Cerwin Vega 280 SE crossover recap ! - Page 1
Forum section: electronics / repair

author: guizmo1967
author_rank: Regular Contributor
timestamp: February 11, 2023, 02:05:08 am
content: Hello,I want to recap my CV 280 SE crossover but I have a question ! I supposed the three big yellow components are capacitors but why the markings 5K 250V or 3.5K 200V ??Usually capacitors are in microfarad ?? What are they if not capacitors ?Thanks for your help !

author: zerowatts
author_rank: Newbie
timestamp: February 11, 2023, 03:44:43 am
content: Nope, those are resistors! 5K and 3K are the resistance values, 5000 and 3000 ohms respectively.But yes, Farad is the unit used to measure capacitance.200 and 250 V are of course the rated voltages for the resistors.Hope it helps, good luck!

author: floobydust
author_rank: Super Contributor
timestamp: February 11, 2023, 04:12:10 am
content: Those are (yellow) mylar film capacitors and don't dry out like electrolytics, I would not replace them unless they are cracked. TBH the crossover looks fine and I would leave it alone.I believe K here means uF, so there are two of 5uF 250V and 3.3uF 250V and not sure of the markings on the smaller ones. The power resistors are square and cement coloured.SolenQuebec has a very good film cap lineup for crossover networks but their prices might be a bit crazy now.Mouserofferings.Polypropylene: Nichicon MPH series, Kemet C4G. I never liked Panasonic ECQ.But these are all bigger and a PITA to mount so they don't fall off and buzz and rattle. A 400V part is way overkill.

author: guizmo1967
author_rank: Regular Contributor
timestamp: February 11, 2023, 04:35:40 am
content: Well guys you got me confuse !!zerowatts says they are resistors and floobydust says they are capacitors??resistors have resistance value and sometime wattage marking on them.Capacitors have capacitance values, usually in microfarad and voltage marking on them.So which one of you guys is right

author: beatman
author_rank: Regular Contributor
timestamp: February 11, 2023, 05:26:22 am
content: yellow ones is film capacitors.the white one rectangular is resistor.

author: floobydust
author_rank: Super Contributor
timestamp: February 11, 2023, 06:00:44 am
content: You need capacitors in a crossover network and... spot them. Two for the midrange, one for the tweeter...

author: Electro Detective
author_rank: Super Contributor
timestamp: February 11, 2023, 07:04:48 am
content: I'm betting those components are still near new and up to spec.I would leave the circuit as is, and gently heat up that glue and pick away gently, and remove all of it.There is a good chance the amber glue acts as bridge between the componentsThe speakers don't know what's going ondue to shifting crossover frequencies and other headachesas the glue changes characteristics due to tempreature and the load (audio) pumped throughLose the glue and use a neutral rubber silicone or anything stable and not conductiveA few zip ties or cable ties can't hurt, especially to secure the flapping wiresIf it was mine and the components are solid on the board once the glue is gone, I would not bother and call it job done.Your speakers will thank you for freeing them from classic 'idiot glue' slavery and serve you happily!

author: Haenk
author_rank: Super Contributor
timestamp: February 11, 2023, 08:25:25 am
content: I'd say there is likely one bipolar electrolytic, which might or might not went dry. Without LCR meter, replacing it cannot hurt. Leave the other parts alone, they are really unlikely to need replacement.(yellow foiled aluminium can on the right PCB, middle/right, brighter yellow than the film caps)

author: CaptDon
author_rank: Super Contributor
timestamp: February 11, 2023, 01:57:46 pm
content: ZeroWatts, you are so wrong, they are not resistors!! Ever seen a resistor with a voltage rating printed on it? Those are standard mylar caps non-polarized and found in nearly every passive crossover. Really?

author: Gyro
author_rank: Super Contributor
timestamp: February 11, 2023, 02:22:25 pm
content: Quote from: Haenk on February 11, 2023, 08:25:25 amNo, I think that's a film one too. I suspect that it is relying on the natural HF roll-off of the bass driver rather than electrically crossing it over (there's no heavy inductor either, just the small air cored ones).Cerwin Vega are one of those US brands that favour in your face bass over sublety.

author: themadhippy
author_rank: Super Contributor
timestamp: February 11, 2023, 02:27:11 pm
content: I always thought K on a capacitor meant 1000pf,but 5000pf seems a bit low unless your crossing over for batsQuotemake sure the locking tongue aint metal though as it may upset the delicate magnetic fields,ive tied the compounds on my crossovers down with string to avoid such issues

author: coromonadalix
author_rank: Super Contributor
timestamp: February 11, 2023, 04:05:07 pm
content: the yellow are capacitors the grayish rectangle ones are resistorYou dont need to recap theses crossoversi was an audio techcerwin vega are basic speakers, done tons of voice coils kits / and redo the speakers / supension foams etc ... in them, they are easy to saturate and get voice coils problemsIf you need to test speakers, you need an amplifier with an audio generator, you test the resonances frequencies and he full bandwith passing thru the crossoveri satrt at very low frequency like 1 hz or lower to see the sub woofer movement and hear if it scratch in a way and frequency up ....some members here are totally wrong

author: guizmo1967
author_rank: Regular Contributor
timestamp: February 11, 2023, 05:17:55 pm
content: Thank you for all your feedbacks !!The reason why I wanted to recap those crossover is because one of the tweeter (left speaker) seems weaker than the other !! To rule out the amp as the problem, I switch speakers and now the weaker tweeter is the left one, so definitely speaker related !I removed all tweeters, mids and woofers to measure resistance and the tweeters are equal, mids are equal and woofer are equal in resistance !!There are two pots, one to adjust the tweeter and one for the midrange.What do you think could be the problem ? Potentiometer, capacitor or the glue between components ? Where would you start ?5K and 3.5K on those capacitors means what ? 5000 micro or nano or pico farad ??Quote from: Electro Detective on February 11, 2023, 07:04:48 amI will remove the glue, good advise

author: zerowatts
author_rank: Newbie
timestamp: February 11, 2023, 08:04:42 pm
content: I'm sorry, stupid mistake. Please ignore my comment above. Those are capacitors indeed.Voltage rating are for capacitors, resistors have wattage/power ratings.As mentioned, those are film capacitors. I do not have much experience with those. And a crossover circuit has to have capacitors (reactive element) in them, so it could never be resistors as I previosly mentioned.guizmo1967 please disregard what I have said above, I was indeed wrong, rookie mistakeI am still learning, sorry guysCheers!

author: floobydust
author_rank: Super Contributor
timestamp: February 11, 2023, 08:37:12 pm
content: The rheostat control is likely for adjusting the tweeter level, check how it is set compared to the other channel. It might be set lower in the left speaker. These can get oxidized too, so rotating the control back and forth a few times can fix that.Otherwise I would leave the crossovers alone, don't blame the capacitors.

author: themadhippy
author_rank: Super Contributor
timestamp: February 11, 2023, 08:45:14 pm
content: Quotetheoretically you could just use inductors

author: guizmo1967
author_rank: Regular Contributor
timestamp: February 11, 2023, 10:35:41 pm
content: Quote from: floobydust on February 11, 2023, 08:37:12 pmDo you mean when both tweeter knobs are in the middle and then measuring resistance directly at the rheostat with a multimeter, to check if they have the same value ??If you look at the picture, the potentiometer for the tweeter has a resistor and a capacitor across it. Do you think the cap may be faulty, that's why the difference between both tweeter ??I did rotate the control back and forth a few times but did not Deoxit them yet !QuoteNo one answered this question yet !!!

author: beatman
author_rank: Regular Contributor
timestamp: February 12, 2023, 04:37:02 am
content: it looks like 5μf.

author: floobydust
author_rank: Super Contributor
timestamp: February 12, 2023, 05:44:22 am
content: I said in Post #2 they are 5uF and 3.3uF. Quit blaming the capacitors lol.For the tweeter which seems quieter than the other, also check polarity of the tweeter and midrange is correct or at least the speakers match. If one is out of phase, the sound field will be weird, stereo image off to one side and freq. response not so great. I'd check DC resistance of just the tweeter to see if matches the other as well.

author: Electro Detective
author_rank: Super Contributor
timestamp: February 12, 2023, 09:15:34 am
content: Quote from: guizmo1967 on February 11, 2023, 05:17:55 pmI count 5 capacitors, 3 brick style resistors, 2 coils/inductors, 1 variable resistor/rheostat,and what looks like a small black switch = does everyone concur?Again, ALL the glue has to go, or it can stay but at the least cut away where the glue joins components,this will save time and stress, and no one will see (or care about) the cuts once back in the speaker boxNext is to check all the soldering by tugging/pulling on joins gently to see if they just snap off, or changes in soundThe solder may look great, but usually the assembly line people do not clean to prep the componentsand just overheat and pray the flux 'grips'.Add to this dirty crust on the soldering iron tips that are not sponge wiped, crap that goes into those bulky solder joints.Over time all this unnecessary rush rush halfassed assembly procedure are a FAIL waiting to happen over time,and does no favors to people that appreciate a decent balanced audio sound.I have had issues like this with cheap and big dollar crossovers in the past,and pulled and jiggled the wiring whilst running audio and constant and swept frequencies,listening to the speakers etc for 'changes'.One time, the best looking shiniest solder joint on an expensive pro crossover board, just broke off with no force at all.The flux underneath was holding it together and before that the sound was changing as the wires were moved or by tapping on the board etcOther times the wire/s just pull out of the joints, or wire strands burnt to oblivion, or tarnished and 'fluxified' (?!!) under the joint and not obvious.It's quite likely many great sounding passive speakers past and present, regardless of price (and audiofool bs),were wired and soldered correctly, and polarities checked and verified, especially the tweeters and high midrange etcor some got it right by chance.Manufacturers balls about with designs and marketing, and yes some mean well because they like audio and want the company to get a rep and make money etc,but drop the ball with clumsy dumbass assembly practices,policies usually driven by company buyout merge-tards and their clueless math junkie bean countersMaybe I should thank such corporat clowns, for the unwanted encouragement to learn electronicsto fix their 'get it out the door..' arrogant production attitudes, for products I paid good money for,so once sorted properly by me, I could finally crack a beer, relax and listen to the audiowithout figuring what's not right, or maybe wrong purchase decisions, issues with my hearing,left is louder or right is quieter, or vice versafailing speaker drivers, the CD player and amp are rooted,perhaps mice and cockroaches have set up shop via the speaker ports,or perhaps the recording people blundered the mixdown (unlikely..)maybe I should sell the car or refinance to buy a couple of meters of audiofool grade cable tooso I don't lose any more nano-Bells of sound

author: Gyro
author_rank: Super Contributor
timestamp: February 12, 2023, 11:10:02 am
content: Quote from: Electro Detective on February 12, 2023, 09:15:34 amWow, where did all that come from?The glue is there to stop the components rattling. Those crossovers are almost air wired, just a few rivets in the fibreboard. I can't see it noticably bridginganyconnections and as for it not bridging the insulatedpackagingbodies of components!Even then, it's a speaker crossover, not a preamp or an electrometer!If you remove all the glue, you'll inevitably damage the outer plastic of the capacitors by pulling it or scraping it off. You'll only have to replace it with more glue anyway to keep the assembly structurally sound enough to be inside a speaker cabinet. You can check the solder joints without removing the glue.This no-glue thing is just more audiophoolery!EDIT:QuoteNo, there's another pot hiding under the 15R resistor on the left or the picture.

author: jonpaul
author_rank: Super Contributor
timestamp: February 12, 2023, 12:30:50 pm
content: As audio designer since 1970s, I can say that the capacitors are the yellow cylenders, values not pf but between 100nf...100 uF.Wirewound resistors are gray square crossed section parts.tweeters often get damaged by overloaded power, transients and excessive low frequencyThis is a low end consumer Cerwin Vega, mass production not audiophile99% chance all capacitors and resistance are fine. Xover is not the issue.Buy, or borrow a VOM and test the resistance, some VOM also have a capacity test.The tweeters can be checked with an audio oscillator, just sweep freq 1 kHz..20 kHz listen for clear or weak, distorted tone.Jon

author: Jeff eelcr
author_rank: Frequent Contributor
timestamp: February 12, 2023, 06:22:58 pm
content: The brown glue used does not look like the type that becomes conductive.An ohmmeter can test the glue to find out.Jeff

author: james_s
author_rank: Super Contributor
timestamp: February 12, 2023, 06:29:18 pm
content: What fault are you experiencing that you think replacing capacitors will solve? I would more likely suspect one of the drivers themselves as I don't see any electrolytic capacitors in the crossovers.

author: srb1954
author_rank: Super Contributor
timestamp: February 12, 2023, 07:25:57 pm
content: Quote from: floobydust on February 11, 2023, 04:12:10 amThe value is assumed to be in uF but the manufacturers could have been slightly less lazy and actually printed a 'u' after the number to remove any doubt.The K stands for the tolerance - 10%.

author: guizmo1967
author_rank: Regular Contributor
timestamp: February 12, 2023, 09:16:43 pm
content: Quote from: floobydust on February 12, 2023, 05:44:22 amOk, I willQuote from: jonpaul on February 12, 2023, 12:30:50 pmI have a function generator app on my phone (unfortunately I don't have the real thing), I will go from 1kHz to 20kHz to check if both tweeter sound equal !! I have used that same app when I refoam my woofers.Quote from: james_s on February 12, 2023, 06:29:18 pmOne of the tweeter seems weaker than the other one !!

author: james_s
author_rank: Super Contributor
timestamp: February 12, 2023, 11:50:52 pm
content: Try swapping the tweaters, see if the weak one follows the driver or the crossover.

author: bdunham7
author_rank: Super Contributor
timestamp: February 13, 2023, 12:03:21 am
content: Quote from: guizmo1967 on February 11, 2023, 05:17:55 pmLeave the crossovers alone for now, and probably forever. To diagnose your problem, put it all back together and note which side has a weaker tweeter. Then swapjust the tweeterbetween the two speakers and see if the problem goes with it. If it does, then the problem is the driver itself. If not, then you can start looking at the crossover components, including the adjustable controls, which I assume are L-pads.

author: guizmo1967
author_rank: Regular Contributor
timestamp: February 13, 2023, 03:02:19 am
content: QuoteI put everything back together, used the function generator app on my phone from 1kHz to 20kHz and every frequencies were clear, not distorted and seemed equal. Maybe my ears are playing with me !!! So I'm gonna leave the crossovers alone and like james_s and bdunham7 said, just as a last test, will try to swap the tweeters.I think we can close this thread now, thank you all for your help !!

author: Electro Detective
author_rank: Super Contributor
timestamp: February 14, 2023, 10:13:54 am
content: Apologies to the Forum for the long quote and reply:Quote from: Gyro on February 12, 2023, 11:10:02 amIt's pointless to try debate thisI have seen and fixed more passive crossover issues that I care to remember,and no one should care that I care, unless I can prove it and show the 'pictures'or 'it didn't happen'I was assuming OP may want to tackle the issue 'alternatively' rather than go the long tedious dead end waythat I originally went down, at great cost, added with a reluctant interest to further in electronicsand debunking audiophoolery practices from bs artists from day 1...which only a coerced audiophoolery salesperson with an electronics clue would fully understand,before the internet and online gabbing..Anyway, times change and the years roll by, but everything else stays the sameHoping OP gets their rig to sound ok and not waste time hunting phantomsBest Regards

author: james_s
author_rank: Super Contributor
timestamp: February 14, 2023, 08:51:54 pm
content: It could be room acoustics playing games with you, or the source material you were listening to, or a fault in the amplifier or some other issue. If they sound good from a test signal then they're probably fine. I think my friend had a set of those same speakers when we were teenagers in the 90s, they sounded pretty good to me.

author: max.wwwang
author_rank: Frequent Contributor
timestamp: February 15, 2023, 05:26:30 am
content: Quote from: zerowatts on February 11, 2023, 03:44:43 amAre resistors (all or some) rated for voltage? I've never seen one before and don't quite understand such rating. Why not Watts, or what's the difference from Watts? Is there is limit of voltage to be applies to a resistor within its power rating?

author: james_s
author_rank: Super Contributor
timestamp: February 15, 2023, 07:33:44 am
content: Quote from: max.wwwang on February 15, 2023, 05:26:30 amSure, they almost always have a voltage rating, although it often isn't prominently displayed. Excessive voltage can cause a resistor to flash over, depending on the resistance you can hit either the voltage or the wattage limit first. For an extreme example, a 10M resistor rated for 1/4W would need 1,581V across it to dissipate 1/4W. That voltage would arc through many small 1/4W resistors.