1000.1 uf ???

[ic-racer]

I'm working on a 12v supply for my Fender conversion and I am using this schematic. But I don't understand the extra 0.1 uf capacitor. Is there an error in this schematic?

https://tubeamparchive.com/download/file.php?id=2815

(I am making a reference to the 1000uf in parallel with the 0.1uf in the upper power supply diagram. Since capacitors in parallel have a summed capacitance, the total capacitance in would be 1000.1 uf for those two capacitors. Why does it need to be so exact?)

[mdroberts1243]

I'm working on a 12v supply for my Fender conversion and I am using this schematic. But I don't understand the extra 0.1 uf capacitor. Is there an error in this schematic?

https://tubeamparchive.com/download/file.php?id=2815

(I am making a reference to the 1000uf in parallel with the 0.1uf in the upper power supply diagram. Since capacitors in parallel have a summed capacitance, the total capacitance in would be 1000.1 uf for those two capacitors. Why does it need to be so exact?)

Different caps have different response times... this is often done to have a very quick transient response... the 0.1 has a lot less effective series resistance. In the logic world it is a nessessity to have 'fast' ceramic decoupling caps in addition to the bulk filter caps.

[ic-racer]

Different caps have different response times... this is often done to have a very quick transient response... the 0.1 has a lot less effective series resistance. In the logic world it is a nessessity to have 'fast' ceramic decoupling caps in addition to the bulk filter caps.

Ok, so it may actually be doing something. I bought it, but was starting to feel stupid putting it across that 1000uf cap as I was laying out my little fishpaper board. I do notice that your '100w HRM in bluesmaster style' 12v supply does not have this capacitor in its schematic.

[mdroberts1243]

Hey I didn't say you needed it, just what it does!

Personally, I don't think you need it in a relay supply. IMHO, the only thing that is important in this case is that you have enough bulk electrolytic capacitance to make sure the voltage regulator is stable.