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Bipolar/nonpolarised capacitors |
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kingkwak 
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Joined: 08 October 2010 Location: sussex Status: Offline Points: 810 |
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 Topic: Bipolar/nonpolarised capacitorsPosted: 06 May 2014 at 8:04pm |
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Can anyone explain the difference between them? Also the best place to buy capacitors for crossovers.
Have bought some cheap crossovers on fleabay to play with the inductors, but need to get a selection of caps to build the test prototype crossover.
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To much power? NEVER.
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Dub Specialist Sound
Old Croc 
Joined: 15 November 2013 Location: Smethwick Status: Offline Points: 4873 |
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Posted: 06 May 2014 at 11:57pm |
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Arnt they are the same just a different way people call them...
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Musical Roots Reggae Vibration is Life! for music is sound...sound is vibration...vibration is energy... and energy begets life. Therein lies my passion!...MUSIC IS LIFE...
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TONY.A.S.S.
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Joined: 21 February 2007 Location: United Kingdom Status: Offline Points: 6878 |
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Posted: 07 May 2014 at 12:32am |
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What you want to know can be researched, and it's easy to locate the right caps, there are various suppliers who sell imported caps but there are british made ones too, such as Ansar, who supply people in our industry as well as some Hi End Hi Fi companies.
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madboffin
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Joined: 03 July 2009 Location: Milton Keynes Status: Offline Points: 1538 |
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Posted: 07 May 2014 at 11:23am |
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"Non-polarised" in a catalogue usually refers to the electrolytic type. They are, effectively, two electrolytic capacitors connected back-to-back.
Although many low-budget systems use them, electrolytic capacitors should not be used for passive crossovers. They are much less reliable than the plastic film types that are used in professional quality systems. But they are a lot cheaper. If you're building your own system, you may as well do it properly... |
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KidCreole
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Joined: 06 November 2013 Location: London (East) Status: Offline Points: 3600 |
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Posted: 07 May 2014 at 11:28am |
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I get mine from ebay
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kingkwak
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Joined: 08 October 2010 Location: sussex Status: Offline Points: 810 |
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Posted: 07 May 2014 at 8:12pm |
Research is easy when you know what your after. From what I have seen and read so far Im going for plastic film caps, just didnt know what is a good brand or not. Will look into Ansar as an alternitive for the final build. 4 Years ago I had never designed and built a cab, and although I used off the shelf and what I already had in the way of components the end result isnt to shabby. I learnt one hell of a lot doing it and has left me playing with the figures and planning further cabs. The crossover is the last part of a ground up build for me to get my head arround, but dont want to do the rest of the build an injustice by getting it wrong. Im lucky enough to have someone help me wind some inductors now and give me a few pointers on the rest. On the topend Im looking at using lamp protection, how will this affect any atenuation I put in?
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To much power? NEVER.
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studio45
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Joined: 16 October 2007 Location: United Kingdom Status: Offline Points: 3864 |
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Posted: 07 May 2014 at 10:37pm |
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+1 on never using electrolytic caps in crossovers especially high-powered ones. I've recently had to replace caps in some Peavey Hisys 15+6+1 midtops and 15" bass bins - the manufacturer had fitted 100 volt non-polarised electros throughout, which had all exploded into confetti and smoke by the time the cabs got to me (they are owned by an "enthusiastic" Northern Soul DJ.....)
I've replaced all with 250v polyester film types which are about 10 times larger physically - big yellow blocks like square lemons - and quite plainly much more robust; not only do electrolytic types potentially induce distortion due to different forward and reverse current flows, but also can handle much less AC current overall as there is liquid electrolyte in there to heat up and boil off/pop the casing. I would find it very useful if manufacturers were able to give some kind of long-term AC current rating for the types of caps used in crossovers, such data is normally only given for low voltage electrolytics used in power supplies. I tend to go by a rule of thumb of not using anything less than 250v rated for PA work and not lower than 100v for hi-fi, reasoning that the voltage rating is somewhat proportional to the current rating. Using a series lamp for protection will reduce the amount of series resistance required in your attenuator, based on the cold or "off" resistance of the lamp; this becomes part of the series resistance of any L-Pad you may be using. For example if you were using a 6dB pad (8 ohms parallel, 4 ohms in series) and had a lamp with a cold resistance of 2 ohms, you would only need a 2 ohm series resistor to make up the pad and end up with correct attenuation.
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Studio45 - Repairs & Building Commotion Soundsystem -Mobile PA
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markie
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Joined: 31 October 2005 Location: Sunny Liskeard. Status: Offline Points: 4570 |
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Posted: 07 May 2014 at 11:16pm |
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I started to try and learn about crossovers but it was all a bit beyond me. I have a quantity of decent caps if you're interested:- They have various brands from Turbo***** to Supersound, also Ansar and a few with ASS on them but they are all made by the same company who produce them for all the former.
 I also have a quantity of metal clad resistors for L-pads:-  Edited by markie - 07 May 2014 at 11:23pm |
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If it's got wheels or tits it's gonna cost a fortune
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madboffin
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Posted: 08 May 2014 at 5:38pm |
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The "Solen" brand are quite popular in professional applications. They were (probably still are) made by the French company SCR.
You can get them in a lot of non-standard values i.e. outside the usual E6 and E12 ranges. |
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kingkwak
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Joined: 08 October 2010 Location: sussex Status: Offline Points: 810 |
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Posted: 09 May 2014 at 8:31pm |
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Turbosound used eleytone if memory serves me right, electrolytic caps were fitted on them as well as plastic film caps. Think it depends on high or low use.
From what I have picked up so far, Im going with plastic film throughout. Hoping to test this weekend and and start on the L-pad, have a couple of variable resistors on loan. Spent 3 hours lastnight winding the coils, think that once I have got the crossover organised im going to buy over sized inductors and unwind to size.
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To much power? NEVER.
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csg
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Joined: 17 September 2007 Location: bedford Status: Offline Points: 6086 |
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Posted: 09 May 2014 at 10:53pm |
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I tend to buy Vishay polyprop 400V film caps from RS. Sound very good, and not expensive.
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“The fact is this is about identifying what we do best and finding more ways of doing less of it better”
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TONY.A.S.S.
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Joined: 21 February 2007 Location: United Kingdom Status: Offline Points: 6878 |
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Posted: 10 May 2014 at 1:10am |
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Ansar is a name banded around a lot when it comes to Capacitors, and you should know that they will make you any value you want at various voltages.
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TONY.A.S.S. wrote: