Mundorf Mcap Supreme EVO as bypass. Is outsie foil plus or minus?

[Yoshimitsu]

Hey
The power supply of my tube amp has 3x 220uF electrolytic capacitors. I'd like to bypass those caps with some Mundorf Mcap Supreme EVO 0.1uF. Mundorf website states: "
the longer lead also indicates the capacitor’s outer foil."

So, should I solder the longer lead to the positive or negative pin of the big electrolytics?

I know that the outer foil should point towars the lowest impedance point but Idk if positive or negative has lower impedance.

 

[raymondj]

Possibly outer foil to the lower potential side. The cans of old metal can capacitors were terminated to the amp chassis, either by soldered mounting lugs or mounting bolts through the base flange.

Outer foil closest to ground.

 

[rayma]

Hey
The power supply of my tube amp has 3x 220uF electrolytic capacitors. I'd like to bypass those caps with some Mundorf Mcap Supreme EVO 0.1uF. Mundorf website states: "
the longer lead also indicates the capacitor’s outer foil."

So, should I solder the longer lead to the positive or negative pin of the big electrolytics?

I know that the outer foil should point towars the lowest impedance point but Idk if positive or negative has lower impedance.

Ground will be the lowest impedance node of the circuit.

 

[raymondj]

Do you know if the negative of your capacitor is connected to ground usually at a star earthing point.

If so long lead to negative of your capacitors.

 

[Yoshimitsu]

Do you know if the negative of your capacitor is connected to ground usually at a star earthing point.

If so long lead to negative of your capacitors.

Hi

Thanks for your answer and sorry for answering so late.

I'll attach 3 the schematic, pcb blueprint and how the amp looks inside. The 3 capacitors where I will add the small Mundorf caps are marked with red "X", GND is marked as well.

 

[Yoshimitsu]

Okay if ground has lowest impedance I'll connect the outer foil to the positive terminal of the electrolytics. Positive terminal is closer to GND.

Tyty

 

[rayma]

Normally the outer foil would be connected to the lower impedance node,
which is the grounded terminal of the capacitor.

 

[Yoshimitsu]

Normally the outer foil would be connected to the lower impedance node,
which is the grounded terminal of the capacitor.

The cap doesn't have a grounded terminal. The positive terminal goes to a resistor and then to the rectifier. The negative terminal goes also to a resistor and then to the power tubes and the rest of the circuit.

The rectifier should be connected to the ground as well.

 

[rayma]

Unless you have a schematic, just connect the film cap directly across the electrolytic.
That is an unusual circuit if the negative terminal of the electrolytic is not grounded.