The voltage on the output goes from positive to negative.
With a fast transient the cap output is still at the max negative value while the amp output rises to the max positive one.
As in the output is at -14V, the other lead has +42V, difference is 56V.
All things relative, how many people will ever drive a P1.7 to it's full output swing ?
Most electrolytics handle surge values which are 10V higher, Black Gates are likely no different.
First time i've used BG's was around '88/'89, but i've never checked their surge capability and the Rubycon paper datasheet doesn't mention it.
Same story as with diesel engines, Babowacka can confirm that if you run a diesel at 100% power continuously it will break down, but on 85% MCR it keeps on going.
With a fast transient the cap output is still at the max negative value while the amp output rises to the max positive one.
As in the output is at -14V, the other lead has +42V, difference is 56V.
All things relative, how many people will ever drive a P1.7 to it's full output swing ?
Most electrolytics handle surge values which are 10V higher, Black Gates are likely no different.
First time i've used BG's was around '88/'89, but i've never checked their surge capability and the Rubycon paper datasheet doesn't mention it.
Same story as with diesel engines, Babowacka can confirm that if you run a diesel at 100% power continuously it will break down, but on 85% MCR it keeps on going.
spzzzzkt said:
if you check the P1.7 threads you'll find that most people are measuring round 14V across the input caps and about 28V across the output caps - unless they have made a build error.
Oddly enough the 50V BG N's have been trouble free for almost 2 years in my P1.7 clone.
Yeah . . . the output coupling caps are blocking dc of about 30V+/-10% and the input coupling caps blocking dc of half of it. So, no doubt that most people are measuring round 14V across the input caps and about 28V across the output caps. But, since these are only with respect to dc voltages, we have to consider the ac voltages (signal voltages) in addition to the dc . . .
I think that Papa has designed P1.7 for ac signal output to swing max about 50V p-p, i.e. ac signal amplitude of about 25V. So, the output caps have possibility to see maximum about 55V.
I believe that your music listenging loudness is ,however, not going up to this level so that your output caps are safe, seeing the max voltage less than 50V . . .
Cheers,
>
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Elna Silmic II
Nelson Pass recommended that I try these caps when I briefly spoke to him at the last Burning Amp Festival. I was skeptical at first, being a big fan of Black Gate N caps. Anyway, I tried the Silmic IIs in a CD player output stage signal cap application and compared it to the same CD player using Black Gate N caps. To my surprise, the Silmics are more detailed and smoother in a natural way, especially in the treble region. The tone is more textured than with the Black Gates. Moreover, the sound is more coherent with better pace, rhythym and timing. I always find myself subconciously tapping my feet listening to music using the Silmic caps in place of the Black Gates. The best part is that they don't require the long burn-in that the Black Gates do. I still love the Black Gates for that special midrange, but I think the Silmics can do just as well if not better.
Nelson Pass said:Try the Elna silk caps from Digikey.
Nelson Pass recommended that I try these caps when I briefly spoke to him at the last Burning Amp Festival. I was skeptical at first, being a big fan of Black Gate N caps. Anyway, I tried the Silmic IIs in a CD player output stage signal cap application and compared it to the same CD player using Black Gate N caps. To my surprise, the Silmics are more detailed and smoother in a natural way, especially in the treble region. The tone is more textured than with the Black Gates. Moreover, the sound is more coherent with better pace, rhythym and timing. I always find myself subconciously tapping my feet listening to music using the Silmic caps in place of the Black Gates. The best part is that they don't require the long burn-in that the Black Gates do. I still love the Black Gates for that special midrange, but I think the Silmics can do just as well if not better.
freakyone said:
Some people think so, and some think not so much as long as they're not too shabby. NP tends to not spend too much effort on exotic passive parts and he thinks that most of the sound of a circuit is determined by the topology and the active devices (transistors).
I'm no expert on exotic caps. But I can tell you that overall, it's most conventional to use film caps, something like what you show above, for an application like you have in this case. But polypropylene is most recommended if that's not what those are.
The Black Gate N caps were popular because they were inexpensive (I think) and did the job well. They were less conventional in that they were non-polarized electrolytics, essentially two electrolytics in series with like polarities attached to one another. But I understand that they aren't made any longer and aren't available.
Here in the US, there are several brands of polypropylene film caps available in a 10uF size, 200V or more, for prices in the US$2-6 range that might do the job well. I only have experience with the Axons that I used in a Pearl phono stage that I built (they were recommended by Pass) but others might do the job as well. Usually obtainable from sellers of speaker components for use in crossovers.
About those Elna silk caps.... they are inexpensive. You're looking for 16 capacitors all together so expensive capacitors will add up. But you could for instance try two of the 100uF silks in series in the place of the 3 10uF caps at the output. If you use the 35 volt ones, that would be good for 70 volts and give you 50uF. I think that wouldn't cause any problem at the output. If you want to try that, don't forget to connect them with like polarities connected together.
Th Silmics might be inexpensive but they are very, very nice. I've swapped out the BG N's in my P1.7 for 10uF/100V and 47uF/100V silmic II's. The difference was immediately audible - these are smooth, detailed and these qualities have improved over the past few days as the caps have burnt in. I'd concur whole-heartedly with rhings comments above. The BG's won't be going back in any time soon. 
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