It's cheap to get someone else to drill the holes. (Don't you use a board house?) And the caps aren't that big... depending on the value. Though Panasonic stopped making polyP and now there seems to be only Wima.
George H.
George H.
Digikey has PPS in stock.
Digikey also has acrylic film chips listed but no stock..
Yep. NPO is the old (ancient?? ;-) name for C0G dielectric.
Not sure what a "highish" value is, but I'm thankful in the work I do that I have 0.1uF 50V C0G in 1206 SMT case size, and I can get up to
1uF 50V in thru-hole. Even 0.1uF is quite useful in audio range active filters--my work these days encounters that mostly as PLL loop filters, but for low phase noise, a lack of microphonics in the loop filter caps is a big plus. They also have much lower dielectric absorption than the high-K ceramics. That makes them useful in integrators. There are times when other caps are appropriate, but it's nice having an SMT part that's a whole lot better than the high-K ceramics and doesn't get destroyed in SMT processing. (I've found polyprops to be extremely nice if you want something with a very slow self-discharge rate. I think I posted something about my tests on that here in SED some years ago...)Someone else mentioned the glass dielectric caps. I have a bunch of those, and have never thought all that highly of them. They're OK in most respects, but the dielectric absorption is pretty terrible, actually. I think Bob Pease mentioned them in one of his "dielectric absorption" columns.
Cheers, Tom
Vishay has the old Roederstein series too. Currently using MKP1837 which are 1% tol. Not all the E192 serie though :-( In fact just the E6 decade between 10 and 100nF, but hey, it's still there...
-- Thanks, Fred.
I'm a hobbyist/entrepreneur/designer/researcher. I make my own boards..
I like the challenge of cramming everything onto a small space. :)
Am working on an ultra sensitive 100kHz at moderate amplitude (10ish volts) application where the coil copper is demonstrated to cause distortion (copper purity but, the purpose being to detect nG of the sought sample, we can easily detect ppb traces of non linear impurities embedded in the coil) but I had no evidence that the PPS / NP0 caps were guilty. (Tested them against know excellent leaded MKPs).
-- Thanks, Fred.
D from BC a écrit :
If you value your time, even in the slightest way, just use Pcbcart (they're so cheap that even thinking how to not use them pays for the boards). If you're in a hurry, use Manhattan style to test small parts of your circuit. And speaking of cramming the more you can on small board, try to do
4mils-4mils track-space and 4mils vias at home...-- Thanks, Fred.
Yeah.. It's got it's limitations but most of my projects do fine with single side art (at 10mil min). I can have a board exposed and etched in 30 minutes at 2:00am. I can test a design, tweek it, do mods and redo the pcb and have rev 2 done 30 minutes after I press print from the rev2 artwork. I like the iteration speed. :)
I don't deadbug (Manhattan style?),veroboard,breadboard,copper tape,terminal strip,nor wire wrap prototypes anymore.
I make disposable boards. :)
rote:
agic.
cuit
I noticed they cost more used than new. A considerable difference with $500 for new and $2500 used. Perhaps that is because the used cables have been burnt in. Who knows how long you have to play white noise through a new cable to get the sound just right.
I can't comment on that :-)
It's a long time since I did any serious audio work, but I used to use some Siemens unencapsulated polycarbonate types, because they were on a compact (for the time) 5mm pitch, they were 5%, low tempco and available in E24 values. You may remember them, having visibly soldered ends and a layered looking green colour. They were replaced later with polyester types, but E12 range, which is when I stopped using them. The other accepted types are polystyrene and polypropylene, but ceramics were a no-no for filter work because of their tempco and poor initial tolerance.
I don't know anything about "low distortion caps", as the active components usually contribute far more distortion. We used everything from bead tant to direct coupling and had no trouble attaining distortion figures of 0.02-0.005% total on a Radford DMS. In general, a lot of the so called audiophile stuff is bollocks from what I can see and little more than a marketing exercise to the naive. You get more coloration and nonlinearity from a typical set of speakers imho, than any other link in the chain.
Still have my set of JBL Century 100's though, 25 years and counting :-)...
Regards,
Chris
o
You young wipper snappers think you know everything
10 or 100uF in C0G would be a bit hard to find.At 10Hz
1/(2 * pi * 0.1uF * 10) =3D 126KThis is a bit high for low noise work.
I'm in the wrong business:
Steve
no
nThe PPS caps are just too touchy.
I will continue to switch to leaded if I need something I can't do with ceramics.
.
Thanks Fred, Not really much of a range (sigh). Who do you buy them from? We bought a lifetime supply of the panasonic 2% polypropylene, before they went away. But for new products Wima seems to have the best selection (purchased from Mouser.)
George H.
How do you make your own? Not that horrible chemical etch? For $100 you can have three relatively big boards made... you can put different boards on the same gerber and then just slice them up at home. Or do you have more time than money?
George H
So am I. I wonder what the science behind all the 'burning in' of cables is based on. Driving out all the naughty free electrons perhaps :-) ?.
I don't know how they have the chutzpah (I think that's the right word) to look people straight in the eye and sell such stuff. Their valve preamp looks a bit iffy at $1200 as well, though at least it has nice polished wood sides and probably does work...
Regards,
Chris
So am I. I wonder what the science behind all the 'burning in' of cables is based on. Driving out all the naughty free electrons perhaps :-) ?.
I don't know how they have the chutzpah (I think that's the right word) to look people straight in the eye and sell such stuff. Their valve preamp looks a bit iffy at $1200 as well, though at least it has nice polished wood sides and probably does work...
Regards,
Chris
I use the photo method with precoated boards. I etch in a little tray in the sink. No mess. It's the fastest DIY method for small boards. Say 1"X1".
Once I have the board design finalized, (there might be several boards in the garbage due to design oopsies) only then do I consider ordering boards from a fab house. ~Damn it Jim! I'm a designer ...not a factory worker.~
Yup.. I seen those plastics listed on Digikey.
True.. My power amp specs linger around 0.1%.
Oh gee.. I just realized I can use tantalum for my active filters. I'm using single rail and the op amps are biased at 1/2.
Also... It's costing me money :( I'm not fond of spending ~ $1.00 per ea for specialty chip caps. And I need 20.
I've seen speaker rot. Ex: Surround material turns solid.
We haven't had problems with the PANASONIC ECH series parts so far. We've built a bunch of the little filter boards.
John
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