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Adding Bypass Capacitors?

robbie010

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Simon
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Just looking for a little education here, I bought a recap kit for a Revox reveiver and it has been supplied with capacitors that are to be used as bypass caps, mainly little 100nf box caps.

The instructions are in broken english (the kit is from Germany) but it basically says that the caps are to be soldered in parallel on the solder side of the PCB’s. It does say that the units have survived this far without them and that they don’t need to be installed but they wouldn’t be without them.

Can someone educate me on the benefits of installing these bypass caps as apposed to not?
 

technobear

Ursine Wammer
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Chris
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with values like 100nf are they likely to be letting RF leak to ground?
Could be.

I always thought the main virtue of bypass caps was speed. They may not hold much charge but they can give it up faster than a bigger cap thereby having benefits for transient response.
 

rabski

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Could be.

I always thought the main virtue of bypass caps was speed. They may not hold much charge but they can give it up faster than a bigger cap thereby having benefits for transient response.
Depends on the 'what and where'.

The jury is out, basically. IMO and IME they can sometimes be beneficial in power supplies, but I would never use them across signal coupling capacitors. I don't buy the 'speed' argument and the corollary of it anyway is that it could cause 'smearing' because frequencies would be differently affected in terms of timing.
 

JamieMcC

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Proof is in the pudding fit them run for a couple of months then take them out and evaluate without them.

I've used Russian surplus teflons to good effect in the past as well as silver foil Duelunds their JDM bypass cap on the output capacitors and it made one of the most noticeable changes I've yet experienced of any high end foil capacitor tried so far. For £31 each for the silver foils compared to fuses foo speaker cables nos tubes etc it's performance for peanuts imo.
 

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