RIFA is now Kemet. The range is SMR 100V. PPS is a very low distortion dielectric. Bateman has measured it in his epic series in Wireless World. It is a non polarized dielectric with a very low temperature coefficient. It is a Polycarbonate substitute.
The only thing where Polypropylene is better is lower dielectric apsorbtion but we do not have a sample and hold circuit here.
The only thing where Polypropylene is better is lower dielectric apsorbtion but we do not have a sample and hold circuit here.
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The 10nF is a Vishey Roederstein KP1830. It is a PP - Tin Foil. Up to 100kHz I can measure nothing with my equipment at hand.
There was a question about the bias current in the input stage. Measured with the equipment at home it is certainly under 0.1mV from input plus to minus.
Today i brought a more sensitive voltmeter from work and i will look at it in more detail.
Today i brought a more sensitive voltmeter from work and i will look at it in more detail.
I got very used to it. I tried many variants like Veroboard but in the end i prefer ground plane construction for prototypes. It nearly always works right away.
Never tried this type of construction.... seems quite difficult to visualize the sch this way 🙂
Strangly i can build well that way. Taking the known detour is sometimes easier then going the straight way.
That looks really weird but it works well nevertheless. I remember that we had a black and white TV with tubes. Sometimes men in blue suits came and changed some tubes. That where the days of raw and thunder.
I am happy to report that i got the latest version working. In fact i found 2 diodes that where burned. The 1N4148 I used to unload the low ESR 1000uF caps where simply too weak to survive. I am using now UF4007 and that works. The sound I get is very similar then before, so is the noise. At this moments I would say that both versions are very close in performance but I need a bit more time to confirm this judgement.
I am happy to report that i got the latest version working. In fact i found 2 diodes that where burned. The 1N4148 I used to unload the low ESR 1000uF caps where simply too weak to survive. I am using now UF4007 and that works. The sound I get is very similar then before, so is the noise. At this moments I would say that both versions are very close in performance but I need a bit more time to confirm this judgement.
We have an issue with DC that we have not fully resolved. Sorry, both Frans and I are very busy with our day jobs.
We will play the first, perfect playing, prototype on this weekend in Hamburg.
Norddeutsche HiFi Tage, 2. and 3. of february.
Norddeutsche HiFi Tage, 2. and 3. of february.
