0.1uf boards caps

Alby0521 · 1399

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Offline Alby0521

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on: August 14, 2020, 03:43:25 PM
Hello

Is it worth to upgrade the 0.1uf caps on the 2 pc boards? Anyone had good experiences on this upgrade? If so what good brands can be used which don’t brake the bank?

I already got the 10uf, 100uf and 0.1uf(the one attached to the terminal strips) for a future upgrade but I see  that some people upgraded the 0.1uf caps on the boards too so I was interested in any experience.

Thanks in advance.

AB



Offline Alby0521

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Reply #1 on: August 16, 2020, 10:24:46 AM
Hello,

No one had success with the spoken upgrade?

Best

AB



Offline grufti

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Reply #2 on: August 16, 2020, 10:42:15 AM
The questions that you might want to ask yourself is: why is swapping one capacitor for another always an upgrade? What is the function of that capacitor in the circuit?



Offline Alby0521

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Reply #3 on: August 17, 2020, 05:01:00 PM
I’m not completely sure what that cap does that’s why I’m asking here as I saw some people changing caps in that position.

Thanks

AB



Offline Paul Birkeland

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Reply #4 on: August 17, 2020, 06:40:45 PM
I haven't heard huge differences in caps there.  I have had to do some repairs where huge 0.1uF caps have destroyed the PC board because they are too heavy.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Paul Joppa

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Reply #5 on: August 17, 2020, 07:12:10 PM
The 0.1uF cap on the shunt regulator, along with it's associated resistor, stabilizes the feedback loop to prevent oscillation and/or ringing. Don't change the values! It's been a long time since I did the analysis, but if I recall correctly the instability happens at around a megaherz, which would lead sometimes to very hard-to-trace, unpredictable effects.

If you do change the cap, use something physically smaller to minimize RF sensitivity. Don't use Mylar without re-doing the stability analysis because Mylar develops a significant ESR at radio frequencies. Maybe something like mica, or NPO (C0G) ceramic.

Paul Joppa


Offline Alby0521

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Reply #6 on: August 17, 2020, 07:33:34 PM
Hello Paul and Paul

Very clear thank a lot.
I’ll let the caps be on that position.

Best

AB