capacitor material questions

[Svart]

I know we covered this topic over at RO but don't recall seeing it here..

what (dis)advantages would certain capacitor materials have over others?
I am looking for info for polypro, polystyrene and mica caps. has anyone tried our different DIY projects with these? say like the SSL with mica coupling caps(expensive...though) or polystyrene?

:thumb:

 

[sismofyt]

This is a potential can o' worms. Hey, that might make a good cap :green: What's the DA of worms?

Read this:

www.national.com/rap/Application/0,1570,28,00.html

 

[sismofyt]

Also this:

http://members.aol.com/sbench102/caps.html

 

[Gus]

look for the Jung and Marsh stuff on caps www.capacitors.com IIRC. I don't think you are going to get much better than polypros in some circuits if you want clean.

Maybe in a circuit with much lower signal levels poltstyrene or teflon might make a difference.

 

[sismofyt]

Air is better than polyprops... they just tend to get ehh.. HUGE :shock: :razz:

 

[Svart]

those are very interesting and informative, thanks all! I've been using Polypros for everything i do so far so i guess I'm on the right track here. I've always wondered how polystyrene would sound, and i have read opinions about them, both good and bad, but haven't had the time(cash) to try them. maybe the next batch of GSSL i'll be starting soon will have them included. would you say that the "soak" of polyester caps lend the smoothing tendency they have on high frequency?

 

[sismofyt]

It's hard to generalize, 'cause there's more to it than DA. Try looking at cap mfg's websites, like ELNA etc.

You can find plastics/polyprops/teflon/poystyrene caps that don't sound too sweel in audio apps, but good ones often sound more smooth than say tants and lytics. Tants always sound grainy to me. Like old Neve. I really like paper in oil caps, they sound really musical.

Subjective terms yes, but it's so hard to describe sound :roll:

It's also worth checking into multicaps. And *audio* caps. Not all are stoopidly expensive (or just plain stupid), I think Solens are very good value and I use them myself. I don't use fancy MITs but they do sound good. I like Jensens and Cornell Dubiliers a lot, both paper in oil types.

My fav lytic is the ELNA Starget (like I've said numerous times) Black Gates/graphite caps are also very nice, but very expensive. I have limited experience with those.

www.partsconnexion.com is a good source for the more esoteric (and not so esoteric) stuff.

I have no experience with the ever so popular (in the US) 'orange drop'. I think they're from Sprague. Geetar amp guys seem to dig 'em.

In Europe RIFA is quite popular and very nice/good value no-nonsense polyprops. They also make some very good industrial lytics. They last forever. I use 'em, when I got the money :green:

A real contender is the ol' red WIMA MKT, which has been around longer than me. It's still a very nice, smooth sounding cap. I see several in the Manley Massive Passive

I have also tried REALLY expensive silver foil Audio Note caps and they NOT worth the dough. IMO that is. They cost as much as an entire DIY project :roll:

I'd really like to dig more into Black Gates/graphites myself. ANyone got any experience?

 

[Svart]

thanks a bunch sismofyt!

I've been using the high grade of panasonic polypros, they are very large but have extra long legs that allow me to use them anyways and I think they are very smooth and clean, especially when used paralleled with 'lytics, you can notice the difference in sound fairly easily.

thanks again for the info!

 

[sismofyt]

Sometimes that parallel trick - in the signalpath - can sound worse than a single lytic. Often you need big caps at the output, like +100yF because you don't know what kinda gear it'll be seeing. So, polyprops become very expensive and bulky. But if you do know, then you can scale it appropriatly. Example; my taperecorder is always at the output of my desk. I never put anything in between. So, I always know the exact impedance here, 'cause it doesn't change. That way I can use a smallish polyprop, because the Zin of the taperecorder is 50 kOhm. And I can eliminate one cap as well. Sounds a LOT better than two +100yF lytics in series! :thumb:

I've experiemented with using really big/high value caps on the output, but I've gone back to using the smallest possible, while still getting 10Hz -3dB. Don't use this corner freq in the whole chain, though, or you'll loose bass. I use this figure for the total system. Adding (many :grin: ) trannies, just makes it a lot more complex. More complex, even with a relative simple system, than I can fathom :roll: So, I do a basic measurement to make sure my lows are where they should be, while using small value polyprops or paper in oil.

I've also taken this approach to the point that I'm scaling the output amps. My latest tube pre have a Zout of roughly 900 ohms, 'cause I've eliminated and output stage & trannie. It sounds fabulous :grin: Very clean, very dynamic, extremely low coloured. Just two triodes (not duals, like the ECC83 which _is_ two tubes in one bulb) and a an input trannie. I'm also using a smallish output cap. I (nearly) always record totally flat with the pre going straight into the recorder, so I don't need those hefty output amps that can do 600 ohm @ +24dBm. I'm a big fan of over-engineering, but sometimes it can work against you.

 

[Mark Burnley]

sismofyt,

Interesting post- I like your idea of designing your gear into your studio- I think this is the beauty of DIY. If you know where the gear is going to "sit" in the audio chain, you can create the specs to perfectly fit into the chain. A lot of commercial gear has to be "omnivore" in nature- i.e. it can connect directly into any setup be it balanced/unbalanced, pro/semipro levels etc. Is all of your studio unbalanced now?

BTW, You just hit the 16k posts on The Lab!



Mark

 

[sismofyt]

It's my gear, nobody else is using it. I'm not using it anywhere else than my place. So that gives me a huge advantage I think. I don't need to design it to 'worst case scenario', 'cause there ain't gonna be one

No, it's not totally unbalanced. I'm not some kinda purist/audiophool journey here :green: sometimes I like input/output trannies and they're naturally balanced. All my Telefunken/Siemens gear have trannies and all my pres have input trannies as well. But as far as CMRR and hostile RFI enviroment, I can look past that. I run most linelevels unbalanced around 0dB. Makes it a lot easier really. Nearly all studios I've seen/used, are frankly pretty messy (electrically that is). Even the top notch SSL ones :roll:

It's just so easy for us engineer/DIY/gearslutz to break it down into seperate components and look at the desk, or compressor or loudspeaker individually. That's no good, imo. It's a complete system.

I've fixed a few studios that was a mess, but had okay gear. It helped a LOT to sort out grounding and AC power, multicables etc.

Don't wanna sound like an ol' fart ('cause I'm only 29 :wink: ), but you do not have to know jackshit about electricity/-tronics to run a studio today. Or so it seems. This is the bad thing about the DAW revolution. Most people I meet, don't even know what 'ohm' is, but they can PT from here to eternity :roll:

This isn't suppose to be a rant, sorry. I just got carried away :roll:

 

[Svart]

all of my outboard effects are running unbalanced now. however they are no more than 8ft from the console and running through *mega*shielded cable(bought as scrap from a refurbishing studio). sorry, i know you were asking sismofyt... :green: I also use as few outboard pieces as i can get away with just because i like a more natural sound.

 

[sismofyt]

There's just too much sheep factor in pro audio and it's easy to get ridiculed for thinking out of the box. Sonically, technically, innovatively (is that a word) I think there's a lot going on 'on the other side' aka hifi world. Sure, let's laugh of those damned audiophools, but there are people/companies/gear, that'll just blows the pants of 'pro audio' gear. I would never consider using a professional power amp. They just suck compared to high end hifi. It's one reason why I refuse to use active monitors as well. Their amps suck.

I have never seperated recording from listening. My monitoring chain is my hifi chain. I think I'm pretty smart doing that. Others think I'm a weirdo :green:

 

[Svart]

same here. I use a pair of old bose monitors with a kenwood amp, both older than dirt, but i know how they sound compared to other stereos in cars and homes alike. Knowing your gear is worth more than the most expensive buzz word laden crap.

 

[Svart]

does anyone have info about the differences between metalized polypro and standard polypro?

 

[sismofyt]

I think they're the same. The polypropylene is just the insulator material, you need 'plates', or rolled up alu foil to make a cap. I'd guess yo could say all plastic caps are metalized :?

Not sure though..

 

[Svart]

:green: true, true, but looking at my Digikey catalog shows two clearly different types of caps, Polypro and metallized polypro. there is also some kind of hybrid called PPS, do you happen to know what that is?

 

[sismofyt]

No, not really. There's a gazzillion types and I just googled for a while. My brain hurts :?

 

[sismofyt]

Maybe you should try to find those two caps at the mfg's website and see if there's an explanation there?

 

[sismofyt]

Aha!

"What is the difference between a metallized capacitor and a film-and-foil capacitor?
The difference is in the conductor layers. A metallized capacitor has a layer of aluminum conductor vapor deposited on a dielectric film. This metallization layer is very thin - on the order of Angstroms. Two layers of the metallized film are then wound together, so the cathode conductor is separated from the anode conductor by a layer of film on either side. The metallized capacitor has the advantages of size, simplicity, and price. Its disadvantages are a slight loss of transparency (due to the thinness of the conductor) and a slight intrinsic noise (due to inadequate internal damping). Metallized capacitors also tend to be strongly directional.

Film and foil capacitors are constructed of two layers of film and two layers of foil (the cathode and anode foil). Again, when they are wound, the cathode foil is separated from the anode foil by a layer of film on each side. Film and foil capacitors have the advantage of excellent transparency (due to the enormous conductor volume) and very low intrinsic noise ( due to the high internal damping). The disadvantages are size and price; for the same capacitance value and voltage rating, a film-and-foil capacitor has nearly four times the volume and three times the price. Film-and-foil capacitors also tend to be less directional than metallized film caps.

Does this mean that film-and-foil capacitors always sound better than metallized caps? No. The quality of the film, winding tensions, end termination and lead material all play roles in the overall sound of the capacitor. But we have found that when using the same film, the film-and-foil cap does always outperform its metallized cousin."

From here:

www.northcreekmusic.com/CapacitorFAQ.html