If there is a difference it will show itself in low impedance circuits where there is significant signal current flowing. Not an issue for coupling caps, probably not an issue for filter caps within amplifiers, but I might be cautious about speaker crossovers.
If component manufacturers are using steel wires then it could mean:
1. it makes no difference - and they have checked this
2. it makes little difference - and any distortion is probably within what would be expected for that component type anyway
3. it makes a difference, and they don't care but hope we don't realise
I suspect option 2 is the truth.
If component manufacturers are using steel wires then it could mean:
1. it makes no difference - and they have checked this
2. it makes little difference - and any distortion is probably within what would be expected for that component type anyway
3. it makes a difference, and they don't care but hope we don't realise
I suspect option 2 is the truth.
@Grasso789: I beg to differ but manufacturers call it "tin plated copper-clad steel wire". The stuff you describe is not used by many quality brand names. This "any metal" is used by the lowest on the ladder.
What actually is used by A brand manufacturers is "tinned copper clad aluminum wire". Check (older) datasheets of brands for reference. Don't be surprised to find older parts of a series to have tinned copper wires and recent ones to have tinned copper clad aluminum wires.
"It makes a too large difference in price so we better find cheaper material and see if it is acceptable. Anyone will know that copper is better but they don't want to pay the price and possibly will buy parts from our competitors".
It happens everywhere... Use cheaper stuff and try to convince buyers that it has equal or better properties.
https://sewelldirect.com/learning-center/cca-facts
In my former job very large quantities of CAT6 cabling were bought. One day colleagues found difficult to terminate cabling. By coincidence it turned out to be magnetic. The very sophisticated measurement equipment showed differences and the cabling was found to measure worse over time. Since then all suppliers have to deliver copper only cabling. I have found 10A rated mains cabling with modded IEC connectors to be made of non solderable wire material. I noticed this only after one of them was bad and had a bulging melting part near the connector. Instead of being 0.75 mm2 it was way thinner and the plastic used was thicker and could be cut with a finger nail.
What actually is used by A brand manufacturers is "tinned copper clad aluminum wire". Check (older) datasheets of brands for reference. Don't be surprised to find older parts of a series to have tinned copper wires and recent ones to have tinned copper clad aluminum wires.
"It makes a too large difference in price so we better find cheaper material and see if it is acceptable. Anyone will know that copper is better but they don't want to pay the price and possibly will buy parts from our competitors".
It happens everywhere... Use cheaper stuff and try to convince buyers that it has equal or better properties.
https://sewelldirect.com/learning-center/cca-facts
In my former job very large quantities of CAT6 cabling were bought. One day colleagues found difficult to terminate cabling. By coincidence it turned out to be magnetic. The very sophisticated measurement equipment showed differences and the cabling was found to measure worse over time. Since then all suppliers have to deliver copper only cabling. I have found 10A rated mains cabling with modded IEC connectors to be made of non solderable wire material. I noticed this only after one of them was bad and had a bulging melting part near the connector. Instead of being 0.75 mm2 it was way thinner and the plastic used was thicker and could be cut with a finger nail.
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Aluminium might be o.k., only important possible problem I see is mechanical handling.
The stuff used for RF shielding has stayed the same since a hundred years. Do not beat me but let the young and beaten ones open old TV sets and see!
The term Weissblech is also used for the metal used for tin-cans. Fence wire is similar, for you know rather pure iron, without carbon. Common steel contains carbon, which makes the alloy hard and elastic. Non-corrosive light-weight alloys of iron plus silicon plus aluminium may be also called steel but usually VA.
For anyone interested, the newer Panasonic polypropylene series (ECWF) use steel leads too. Props to Wima for keeping the copper in the higher-end parts at least.
When I have time I'll update the first post with a list of caps I ordered/checked recently, plus data that others contributed on recent purchases. Might only make a minor difference but it would be nice to know prior to ordering either way.
Appreciate your thoughts! Thanks for sharing.
Certainly in the older gear the copper leads are far more common. Hard to imagine it was done without reason. I checked a few ~30 year old amps and interestingly the non-audio electrolytics do have steel leads (just like now), however most electrolytics are copper-leaded "audio" types, and all the film caps ('propylene, 'styrene, mylar) also have copper leads which seems much rarer now.
Are you aware of many film cap lines other than Wima that use copper leads? All the other common brands I have here (TDK / EPCOS, Vishay, Kemet, etc) all seem to use steel leads. It is certainly a little annoying that this isn't mentioned in datasheets. I haven't checked Nichicon films yet.
Not sure if you saw my post #12 but I checked a bunch of recent OSCONs and SEP are steel, but SEPF and SEPC are solid copper. Not documented!
Out of curiosity if you or anyone else has an opinion, is there any disadvantage to using a physically large(r) film cap provided it fits and doesn't need longer leads? I can't see anything in the datasheets but have wondered if there are other concerns (like inductance etc), when using higher value 'prop films (~2uF) in small signal circuits.
When I have time I'll update the first post with a list of caps I ordered/checked recently, plus data that others contributed on recent purchases. Might only make a minor difference but it would be nice to know prior to ordering either way.
Hi I was not being sarcastic. I am used to sarcastic comments when matters like these are discussed. Suffice to say I prefer capacitors with tinned copper lead wires what ever the explanation is. Anyone with a good set of ears will come to the same conclusion when comparing. And even if I wouldn't hear a difference i would still prefer non ferro lead wires as copper is the material of choice in this field. We don't see steel in switches, wall sockets, wiring etc.
Capacitors with tinned copper wire are still being made and I am such a customer that likes to pay a little extra for that. I admit that it becomes harder and harder as even industrial series are now being made with steel wires. What was normal 20 years ago is now called "for audio"
Appreciate your thoughts! Thanks for sharing.
Certainly in the older gear the copper leads are far more common. Hard to imagine it was done without reason. I checked a few ~30 year old amps and interestingly the non-audio electrolytics do have steel leads (just like now), however most electrolytics are copper-leaded "audio" types, and all the film caps ('propylene, 'styrene, mylar) also have copper leads which seems much rarer now.
Are you aware of many film cap lines other than Wima that use copper leads? All the other common brands I have here (TDK / EPCOS, Vishay, Kemet, etc) all seem to use steel leads. It is certainly a little annoying that this isn't mentioned in datasheets. I haven't checked Nichicon films yet.
Thanks, sounds like the MKP4 are copper.
Not sure if you saw my post #12 but I checked a bunch of recent OSCONs and SEP are steel, but SEPF and SEPC are solid copper. Not documented!
Thanks, answers my original question.
Out of curiosity if you or anyone else has an opinion, is there any disadvantage to using a physically large(r) film cap provided it fits and doesn't need longer leads? I can't see anything in the datasheets but have wondered if there are other concerns (like inductance etc), when using higher value 'prop films (~2uF) in small signal circuits.
I find it fascinating too, just looked up that article now to read!https://upload.wikimedia.org/wikipedia/commons/5/58/What_is_stereophonic_effect.png
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In it's homepage, WIMA explains very well how their different types of capacitors are constructed. This (WIMA) ist the construction of metallized capacitors like MKP4, this (WIMA) shows metallized pulse capacitors like MKP10, and this (WIMA) depicts film/foil capacitors like FKP2 which can carry the biggest pulses.
From this it is clearly visible why MKP10's are physically larger than MKP4's of the same capacitance/voltage - they do have just more dielectric within their bodies.
There's no need to prefer the larger and more expensive MKP10's over the MKP4's in small signal applications, but there isn't also a disadvantage to do it. Some benefits might be expected from MKP10's in loudspeaker crossover networks, though.
Best regards!
Yes, these copper clad aluminium wires can be bent only a few times. Empirically tested
I know Weissblech too (weekijzer). Die cast cases for devices that needed shielding also sometimes are/were made from an alloy called zamak.
https://en.wikipedia.org/wiki/Zamak
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I just wanted to share something, while Wima didn't respond to my email, I sent one to Nichicon and they did reply. Unfortunately they didn't answer my question completely (language barrier perhaps) but I did get something. There was some data hidden away in an "eco products" PDF they sent.
It conclusively states the liquid electrolytics that use solid copper leads as only UKZ, UFG, UES, UDB (and LKG-3 with Zn + gold plating).
All other liquid electrolytics use Fe as main lead material.
It is inconclusive on solid polymer caps (says Cu/Sn "or" Fe/Cu/Sn) for through hole types.
I can confirm RNE solid polymer has solid copper leads and I have some RNS on the way so I will check those too.
It conclusively states the liquid electrolytics that use solid copper leads as only UKZ, UFG, UES, UDB (and LKG-3 with Zn + gold plating).
All other liquid electrolytics use Fe as main lead material.
It is inconclusive on solid polymer caps (says Cu/Sn "or" Fe/Cu/Sn) for through hole types.
I can confirm RNE solid polymer has solid copper leads and I have some RNS on the way so I will check those too.
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