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In Reply to: RE: Sorry, that link was for the .... posted by Cougar on May 30, 2016 at 08:01:09
I'm aware of the mod posts and the photos of the V-dac. I count 29 ceramic caps probably all .1uf. Wondering if replacing all of them would be worth while, probable. Again it seems that stacked film are liked better than any ceramics. Don't see any comparisons between different small stacked caps. The world need a stacked film bypass cap shootout. Tweaker
Follow Ups:
No self-respecting DIYer would use a ceramic capacitor for anything but bypassing rectifier diodes or bypassing the power input pins (V+, V-) on an IC chip. But for both those applications, the properties of a ceramic capacitor are desirable; ceramic capacitors maintain their capacitative characteristics at RF frequencies, whereas almost all other types reach resonance or become inductive at such high frequencies. I am sure tweakers (with a small "t") break these rules of construction, but I would advise against it. So, you have to look at your schematic and figure out what each ceramic is doing in the circuit. If it's doing either of the above functions, leave it be, IMO.
Don't have a diagram and don't think I can get one. I think I read that stacked film were designed as an upgrade to ceramics. Do any of these have the good characteristics of the ceramics at high frequencies?? They seem inexpensive. If not could just get a couple of COG's and put them in a couple of places?? IMHO no customer respecting manufacturer should use them either or at least choose a couple of places to put a good cap. Nothing but total junk ceramics, junk electrolytics with a NE5532. What would the hobby be like without manufacturers claiming high quality and using nothing but junk. We might have to listen to music, Big T
Sure. Use a COG if it makes you feel better. I think COG are ceramic, and they do cost more, which must mean they are "better". However, I really do not know whether stacked film capacitors perform well at RF frequencies. You should be able to find a data sheet somewhere. You could use a Dueland costing hundreds of dollars in that application, and it would be less good than using a ceramic. The idea is to filter RF, not to make violins sound better. This is with reference to either bypassing a rectifier diode or bypassing the voltage inputs to an IC or sometimes quelling oscillations elsewhere. By the way, with a Schottky rectifier diode you do not need the bypass ceramic capacitor.
"At the highest frequencies only stacked film should be considered" Walter G. Jung
Jung and the others you mention below may all be thinking of the highest AUDIO frequencies, where I would not doubt for a minute that the stacked film caps would be superior to ceramics. Try to find out how they behave at RF, compared to ceramic.
I now read that the original stacked film capacitors were developed for the purpose of RF suppression. T
I didn't see the RF info or graphs but they may be out there. I'll see if John Curl will weigh in on this. T
Edits: 06/02/16
from what you have read, then go ahead and replace all the ceramic caps with stacked film if that's what you really want to do. Lew is just giving you his opinion and I agree with his points. So why ask, Do what you wish with the caps since you already know what you want to do from what you have read.
The bottom line it's your DAC and your tweaking project. So have fun experimenting.
Both John Risch and John Curl prefer the use of stacked film over NPO (the best) ceramics across -V+V and I would assume in other spots also. Both "heavyweights" in the audio world. It's not just about what I want to do it's about seeking info about what would be very or the most effective from experienced people in part to whittle the choices down. Tweaker
The last thing I would ever do would be to contradict either of those two gentlemen when it comes to audio circuit design. Note that we've been saying all along that you only need to determine how stacked film behaves at RF. Since you apparently had the info from noted guru's that stacked film CAN effectively substitute for ceramics, I am not sure why you felt the need to ask us rank amateurs. Anyway, carry on.
In 2004 John R. stated that stacked film "should" be a good option and John Curl concurred.
It's what he does, repeatedly. tweaker has created dozens of threads and they mostly follow the same pattern - ask a (sometimes stupid) question, act like he's clueless, then when people offer their opinions and/or suggestions, he knocks them down one way or another and reveals that he (thinks he) knows the proper answer all along. Once people twig onto this, he starts a new thread. For instance, see the new one about opamps?
Tox, Thanks for the informative reply. Given your electronic engineering background I and maybe we appreciate your detailed info on the RF characteristics of the high grade ceramics vs stacked film, your personal observation of how they sound in comparison to each other, how different brands of stacked film caps sound in comparison to each other and if there may have been any better caps developed for this purpose since the 2004 comments from JR and John Curl. Good, informative and useful reply for me and anyone else that might be interested in this subject matter. The advancement of this hobby is dependent on quality info like you have supplied. Thanks once again. Sincerely, Tweaker
You have quite a bit of info from different people here and what you read, YOU need to do the leg work now. It's your DAC you originally asked about the ceramic caps. So it's up you now to compare for yourself if you really need that info and what brand of stacked caps work best for you, Just like a lot of other have done.
We are here to help you out and if we have a link/s we can supply that but ultimately you have to do the research. Let us know what your results are. Tweak away!
Well Cougar , some B32529 stacked films are on the way. About the dual op amps a OPA2132 is on the way. Suggestions for OPA2604 and OPA2134 are both very good suggestions. These fets are way more musical... than a couple of bi polars I have listened to that people like,IMHO and the OPA2107. It's give and take between the 2134 and 2604. As in everything else opinions vary hugely. If a lot of others have compared different stacked film caps I am not aware of it and no one has responded as such. I'll put these in and hope for an improvement. As to these caps there is no reams of comparisons like in other caps for coupling and crossovers or for that matter any that I could find. Onward and hopefully upward. T
Some will like other types due to more upper end clarity. I like those two I.C's but prefer the OPA2604's. What resistors are you using in the signal path?
In my DIY preamp I used Mills throughout and have been very happy with them. When it was in the prototype faze I swapped out the mills for some Dales metal film. At first they sound better but after 75 hours they were irritating to me for some reason. The cymbals has a abnormal sizzle. I play drums so I know what real cymbal sound and decay are. So I put the Mills back in and everything I liked came back.
Are those stacked film Epcos? I will looking to this soon when I do my Pioneer Elite PD-59 CD player.
Another thing to consider are the Oscon caps for digital circuits. These work well too.
Let us know your results! Hopefully the B32529's are what you were looking for.
The number is an Epcos number . Epcos, TDK and Siemens are all the same it seems. Blue. No idea what crap resistors are in the V-Dac. If and when I get to changing resistors the Takman MF will be my first go to because of the great reviews. In the old days some form of Corning MF sounded better than any other MF we tried at the time. Dale is solid good but not excellent. It's likely that the Z foils are the best. They should be at what they cost. T
nt.
Both JR and Curl and many other very experienced people belong to this forum. Why would you assume I was trying to get useless info? Also, it took me a while to come up with the 2004 posts by both of them on the subject of stacked film vs ceramic. Also I like to get feedback from a few people on a particular subject I'm looking into, mostly from people who have actual experience listening to the issue at hand. T
nt.
"maintain their capacitative characteristics at RF frequencies"
isnt'it also a property of stacked mica capacitors?
" Stacked film have much better electrical characteristics at high frequencies" so I read. This was in the context of stacked film and rolled construction.
Well I was under the impression that filtering RF did make violins sound better potentially. John Curl seems to think that all ceramic caps are inferior to stacked film. The Siemen Epcos stacked films I looked at are used for automotive RF suppression. I believe that stacked film construction is inherently non or low inductive. A number of people on audio sites use the stacked film in place of ceramic for sonic improvement. They seem to be a known entity. T
Edits: 06/09/16
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