I am aware of the Pannasonic PPS caps but i dit not try them.
I tryed the RIFA PPS SMDs after i read Batemans article in Wireless World and he found that they had very litlle distortion. In fact it was the SMR range that has magnetic wires.
I am not convinced that very low DA is the key to good sound at least when the cap is not loaded by an extremely high impedance. My favorite caps are non magnetic Silver Mica. They have not the lowest DA. I use them in my semi active system. A 10nF that is loaded by a 220kOhm resistor to form a soft high pass filter on my open baffles. I had a lot of professional audiophiles in my home like Stig Björge, Allen Wright, Martina Schöner, Michael Fremer, Allen Perkins, Siegfried Linkwitz, Holger Barske, Sven Bönicke, Hara San, Thomas Fast, you name it and nobody was complaining. I could not even tell how that cap sounds because when i change something in my system the sound canges too. Is that a measure of neutrality ? Maybe.
I tryed the RIFA PPS SMDs after i read Batemans article in Wireless World and he found that they had very litlle distortion. In fact it was the SMR range that has magnetic wires.
I am not convinced that very low DA is the key to good sound at least when the cap is not loaded by an extremely high impedance. My favorite caps are non magnetic Silver Mica. They have not the lowest DA. I use them in my semi active system. A 10nF that is loaded by a 220kOhm resistor to form a soft high pass filter on my open baffles. I had a lot of professional audiophiles in my home like Stig Björge, Allen Wright, Martina Schöner, Michael Fremer, Allen Perkins, Siegfried Linkwitz, Holger Barske, Sven Bönicke, Hara San, Thomas Fast, you name it and nobody was complaining. I could not even tell how that cap sounds because when i change something in my system the sound canges too. Is that a measure of neutrality ? Maybe.
Please, be careful, Joachim. I thought the same way, 30 years ago. I used mica for filters, not PS as I would use today, etc. Low impedance loading creates BIG differences between hi DA and low DA caps. Just look at Walt's and my paper from 1986 on DA in caps. Same cap, 500 ohms , 50K ohms. Please note the difference.
I have gone through this paper and i am surprised too. So far i did not find a better cap in this application. More to the point i simply have no desire to change that cap. Maybe i should set up a comparison. 10nF in Teflon, Polysyrene or whatever is not that expensive and then report what my listening panel found. I can definetly say that i did not like the Cornell Dublier 10nF Silver Micas with magnetic wires In my system they gave a tremendoesly high speed sound that was ultimatively tyring. The problem with switching ( you pointed that out many time here ) is that the quality of the switching arangement is critical, even to the point that suble diffences are swapped. I also found out ( informally over a very long period of time ), that if you change something, the system needs some time to settle. The most dramatic situation is when you change or move a mechanical thing like a loadspeaker or a cartridge. For example it sounds great in your system and then you set it up at a show ( even with the same components ) and it sounds dreadfull for the first two or three days and then suddenly on sunday afternoon it starts to blossom. I found that decissions can not be forced and when i read you "between the line" you have found that out too a long time ago.
Joachim, I'm sure that your system sounds good. Probably better than my system, but this does not make mica the 'perfect' capacitor for filters. It is also relatively expensive these days, and hard to get in high values. In 1977, I designed them into the Symmetry Electronic Crossover as filter components, with Tantalum decoupling caps, and Mylar coupling caps. My major concern at the time was slew rate, and Class A operation. It worked, BUT today I would use polystyrene filter components and bypass caps, and no coupling caps, servo controlling offset, instead.
When I designed this crossover, I also used factory tires on my SAAB Sonnet, as I had for the previous decade, never thinking to upgrade. Today, my tires are Bridgestone extra wide, high speed tires. I am never going back to the relatively skinny tires of my past. It isn't a good automotive performance decision. Same with caps.
When I designed this crossover, I also used factory tires on my SAAB Sonnet, as I had for the previous decade, never thinking to upgrade. Today, my tires are Bridgestone extra wide, high speed tires. I am never going back to the relatively skinny tires of my past. It isn't a good automotive performance decision. Same with caps.
I get the feeling that he won't mention names, if only to spare the feelings of those who were left out.
Best Regards,
TerryO
So far i did not find any active crossover i liked except in the bass so in my system the only filtering components in front of my midrange is this silver mica in front of my poweramp and a passive air coil with litz wire between the poweramp and the midrange . The midrange driver is compensated for rising impedance with a copper sleeve so i do not even need a resistor and cap for impedance compensation. It could be argued that this two passive components do less damage then an active crossover of any construction. Anyway, John, i take your advice seriously and will try caps of other construction in that position. The cap i used before was a Röderstein KP ( NOS in a square blue box, not the round ones ) and that coloured the sound more then the Mica. To do a ranking about who is the most knowlagable audiophile on the planet is stupid. The only Johnny i know is the 7 year old son of my friend in Hamburg. Yes, in Hamburg many people call their children traditionally "Johnny".
Joachim, I was including ME along with Larry, Moe and Curly. It was a JOKE!
Is KP, Mylar? I will check. Mica will work in an emergency, and so will a Wallmart priced passenger car tire on my Porsche. It is just not the best choice. You have a $5,000 phono cartridge and you use mica filter caps. tsk, tsk
Is KP, Mylar? I will check. Mica will work in an emergency, and so will a Wallmart priced passenger car tire on my Porsche. It is just not the best choice. You have a $5,000 phono cartridge and you use mica filter caps. tsk, tsk
Yes, i know it was a joke and what i returned was a joke too. I know, we Germans have a very stange kind of humor if anything at all.
I think a KP is a film and foil Polypropylen but i actually think it was an MKP so that whould be a metalised Polypropylen. I think it was around 0.5uF. I look if i can find it then i send a picture. I am absolutely sure that material is not the only factor.
I think a KP is a film and foil Polypropylen but i actually think it was an MKP so that whould be a metalised Polypropylen. I think it was around 0.5uF. I look if i can find it then i send a picture. I am absolutely sure that material is not the only factor.
Here are the two caps. Before i had the MKP and then i used the Mica. The Mica showns 6.8nF but i use 10nF. Actually now i know one of my sins. I cheated because i compared the
Mica loaded with 220Kohm and the MKP with much less impedance to get the same crossover frequency but that whould put the Mica into a disadvantgae because high impedance brings out the DA even worse. One reason could be that my preamp likes the light loading of 220kOhm more then the lower impedance i need for the MKP.
Mica loaded with 220Kohm and the MKP with much less impedance to get the same crossover frequency but that whould put the Mica into a disadvantgae because high impedance brings out the DA even worse. One reason could be that my preamp likes the light loading of 220kOhm more then the lower impedance i need for the MKP.
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Joachim, I am somewhat knowledgeable about DA and it does NOT go away with loading, at least not with an audio signal. However, you should try a different brand, maybe REL next time. Many audio designers have had great success with Rel RT polystyrene. Why? I cannot easily prove, BUT it is low Q in mechanical resonance, and well made. The DA difference between polypropylene and polystyrene is difficult to measure, but please try polystyrene from Rel before making a decision. There are others just as good, but I know Rel can do a good job.
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