polystyrene or Polypropelene, given the choice
Hey guys, I'm working on a few of my phonostages and some mods, and I have a choice of those inexpensive polystyrene caps, which I understand are very good, or Wima poly caps. Which would you use. The polystryrene are much cheaper, but are they as good. The cost isn't great for either part, so let me know.
Hey guys, I'm working on a few of my phonostages and some mods, and I have a choice of those inexpensive polystyrene caps, which I understand are very good, or Wima poly caps. Which would you use. The polystryrene are much cheaper, but are they as good. The cost isn't great for either part, so let me know.
Ok these are the very inexpensive polystryrenes I believe. I will attack a picture of what I'm talking about, these are the ones from Parts Conextion, and look the same as what I have. They are 75 cents from them.
I have used the Rel cap polystyrene's before, they are quite nice. I would choose them over the wima, but no room on the board.
I have used the Rel cap polystyrene's before, they are quite nice. I would choose them over the wima, but no room on the board.
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Polystyrenes are out of favor with manufacturers because they have to be soldered by hand, no reflow ovens. You can find high quality devices from TRW at hamfests. Polystyrenes were used in the RIAA networks of the Audio Research preamps (or so they are indicated on the schematic.)
I use WIMA polypropylene in a lot of tube stuff.
In the Marsh/Jung articles which I link below, they rank polystyrene #1 for all round quality/value, teflon #1 for quality, polycarbonate #2, metalyzed polypro #3. If you have to use a large value electrolytic, a shunt from one of these materials is helpful.
Articles to read:
http://www.national.com/rap/Application/0,1570,28,00.html
http://waltjung.org/PDFs/Picking_Capacitors_1.pdf
http://waltjung.org/PDFs/Picking_Capacitors_2.pdf
I use WIMA polypropylene in a lot of tube stuff.
In the Marsh/Jung articles which I link below, they rank polystyrene #1 for all round quality/value, teflon #1 for quality, polycarbonate #2, metalyzed polypro #3. If you have to use a large value electrolytic, a shunt from one of these materials is helpful.
Articles to read:
http://www.national.com/rap/Application/0,1570,28,00.html
http://waltjung.org/PDFs/Picking_Capacitors_1.pdf
http://waltjung.org/PDFs/Picking_Capacitors_2.pdf
Unfortunately there seem to be substantial quality differences in those axial styroflex caps and quite opposing oppinions. I saw a Graaf GM70 phono pre with Styroflex bybass caps in a recent review and it was said to be very musical. A small company in Germany (Steinmusic) are promoting their NOS styroflex caps from NSF and claim that they are excellent bypass caps and are substantially better than comparable types. But Allen Wright, in his Preamp Cookbook, warns from using any axial Styroflex cap whatsoever, and he also refers to the RIAA networks of Audio Research preamps.
I am wondering what really makes the difference to the new “boxed” radial Styroflex caps? One explanation could be the way that the leads are connected. I notice that the leads can either go directly to the foil or alternatively a second flat piece of wire connects the leads to the foil. By comparison, KPs and MKP’s usually have the ends of the foils soldered together and the leads attached to this surface.
I have a number of different axial styroflex caps which I was going to use in an RIAA network, but now I am getting second thoughts and I might actually use other caps instead.
I am wondering what really makes the difference to the new “boxed” radial Styroflex caps? One explanation could be the way that the leads are connected. I notice that the leads can either go directly to the foil or alternatively a second flat piece of wire connects the leads to the foil. By comparison, KPs and MKP’s usually have the ends of the foils soldered together and the leads attached to this surface.
I have a number of different axial styroflex caps which I was going to use in an RIAA network, but now I am getting second thoughts and I might actually use other caps instead.
AFAIK, as a rule of thumb, for caps:
PTFE (teflon) > polystyrene > polypropylene > polycarbonate > polyester
And always:
foil > metal film
Polystyrene is not used often nowadays because of the low melting point of polystyrene. This restricts it to hand soldering only by excluding it completely from chip type mounting (no way of controlling heat during soldering).
PTFE (teflon) > polystyrene > polypropylene > polycarbonate > polyester
And always:
foil > metal film
Polystyrene is not used often nowadays because of the low melting point of polystyrene. This restricts it to hand soldering only by excluding it completely from chip type mounting (no way of controlling heat during soldering).
Oh, I'm so glad I wandered into this thread.
Years ago I built a tube RIAA preamp out of the "Revue de l"Audiophile" magazone that used those little clear "rolled up" axial caps. Copper foil. Sounded wonderful, the caps were inexpensive, too.
Never could remember what type the caps were. Seen them from time to time on circuit boards, but didn't know.
Thanks guys!!
Years ago I built a tube RIAA preamp out of the "Revue de l"Audiophile" magazone that used those little clear "rolled up" axial caps. Copper foil. Sounded wonderful, the caps were inexpensive, too.
Never could remember what type the caps were. Seen them from time to time on circuit boards, but didn't know.
Thanks guys!!
Thanks Jacco,
I saw them on Ebay years ago but didn't buy any - seems that I'm a bit late now. I have lots of ERO KP 1832 which I was going to use, with smaller styroflex in parallel to get the correct capacitance. The EROs are supposed to be pretty good sounding but they are also quite big. But then again I might want to try
P.S. You mean Dieter Bohlen
Lots of places still sell polystyrene caps, I just always wondered how they sounded. I had heard a lot of good things, I know Audio Research and Conrad Johnson both like using them as an upgrade, but I wasn't sure if they used better ones than those little cheap ones. Parts Connextion has them available in lots of values. I believe Mouser and Digikey has them available in a range of values. Also Handmade electronics is specialing some NOS Phillips polystyrene caps in the closeout section. I just bought a few to give them a try. I'm glad I brought this up as a question, I like all the replies.
I know the Relcap Polystyrene's are nice, I use those a lot, I really like them, but they are quite expensive for everyday use. Actually I just contacted a small capacitor company that makes custom caps, they make Polystyrene's, and I asked for some samples, they said they could give me some over runs for the cost of shipping. They are made more like the Relcaps than the cheap ones, so it might be a nice stash of good caps, if not, I'm out ten bucks.
I know the Relcap Polystyrene's are nice, I use those a lot, I really like them, but they are quite expensive for everyday use. Actually I just contacted a small capacitor company that makes custom caps, they make Polystyrene's, and I asked for some samples, they said they could give me some over runs for the cost of shipping. They are made more like the Relcaps than the cheap ones, so it might be a nice stash of good caps, if not, I'm out ten bucks.
The problem with the molded polystyrene caps shown so far in this thread is that they are "laid in lead" types (leads are laid in place and held in contact with the foils by the molding process) and are most likely inductive due to the way they are manufactured (one lead in the center of the cap winding spiral, one on the outside). The parasitic inductance may not be a problem with smaller values (< 1 nF), but it might start to be noticable for larger values. The wire contacts are also not very sturdy. As has been pointed out, these caps are very delicate, and a nick with a soldering iron or excessive dwell time during soldering can kill them. Don't wash your circuit board with acetone, either - it dissolves polystyrene.
I generally use whatever polystyrene/ polypropylene caps I can get my hands on for a reasonable price, mostly from surplus sources. Siemens made some molded polystyrene and polypropylene caps with epoxy coating that are more rugged. Rifa had a nice series of polystyrene box caps that are also better protected than the molded types - grab these if you find them surplus, as they are nice and compact. ITW had an interesting series of polypropylene molded film/foil caps similar to the polystyrene types but more rugged. Unfortunately, they used steel leads.
Roederstein has a series of boxed polypropylene caps (MKP1830 series?) that are available in precision tolerances.
I generally use whatever polystyrene/ polypropylene caps I can get my hands on for a reasonable price, mostly from surplus sources. Siemens made some molded polystyrene and polypropylene caps with epoxy coating that are more rugged. Rifa had a nice series of polystyrene box caps that are also better protected than the molded types - grab these if you find them surplus, as they are nice and compact. ITW had an interesting series of polypropylene molded film/foil caps similar to the polystyrene types but more rugged. Unfortunately, they used steel leads.
Roederstein has a series of boxed polypropylene caps (MKP1830 series?) that are available in precision tolerances.
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