Anti Parallel diodes to ground

[spoontex]

Hi,

https://www.diyaudio.com/community/attachments/ground-scheme-3-antiparallel-diodes-jpg.336247/

Anybody can tell me the values of the resistor and capacitor?

Thanks!

 

[MarcelvdG]

Typically something of the order of 220 ohm and 100 nF. More importantly, the diodes have to be big rectifier diodes to ensure that they don't fail open at current levels high enough to blow up a mains fuse of the house.

 

[spoontex]

Yes, I have a pair of 6A4 diodes.

 

[woodturner-fran]

I always read that a pair of 1n4007, 10-47r power resistor, and 10nF cap were the parts of choice for this.....

 

[spoontex]

Fender Reissue 63, have two 6A4 + 15Ohm resistor, nothing else.

https://schematicheaven.net/fenderamps/63_reverb_manual.pdf

 

[Elvee]

Typically something of the order of 220 ohm and 100 nF. More importantly, the diodes have to be big rectifier diodes to ensure that they don't fail open at current levels high enough to blow up a mains fuse of the house.

Indeed, and their construction should be of the metallurgical bond variety: https://www.microsemi.com/document-...allurgical-bond-evaluation-methods-for-diodes
These types always fail as a short, except if the current is sufficient to make them vaporize and explode, which requires a significant energy.
Metal-case types like DO203 look very sturdy, but they have a bonding wire that can act as a fuse, given a sufficient current (or I²time, to be accurate)