0ne 100uF cap or ten 10uF caps (or two 200uF caps...etc)

Hi,

In a PSU (for a tube amp, with a choke, cap, choke, cap config) What would be the result if I substitute say a 100uF cap with ten 10uF caps in parallell, or two 200uF caps in series. Simple math tells you that the total uF will be the same but I do not have the skills to know what will actually happend.

Are there any pros/cons of building a PSU with a single cap of the correct uF instead of a couple of caps giving the same total uF for the cap in question.

Regards,
Fredrik
 
Hi,

In a PSU (for a tube amp, with a choke, cap, choke, cap config) What would be the result if I substitute say a 100uF cap with ten 10uF caps in parallell, or two 200uF caps in series. Simple math tells you that the total uF will be the same but I do not have the skills to know what will actually happend.

Are there any pros/cons of building a PSU with a single cap of the correct uF instead of a couple of caps giving the same total uF for the cap in question.

Regards,
Fredrik

Hi there.
Rod Elliot of ESP recommends using multiple paralleled capacitors rather than 1 large value item.

His comments can be seen here;

Project 101 - High Power, High Fidelity MOSFET power amplifier

Go down the page to Fig. 3 and read the comments below it.

Basically, you can expect better performance and lower cost but offset against this will be greater complexity of build.

I can't see any benefit from using higher voltage rated items in series but if you have lots to hand, why not?

Sandy
 

Gopher

Member
2005-11-25 12:09 pm
UK
It's not as simple as just paralleling them.

The caps can only be placed a minimum of their diameter and a bit apart unless you mount them on both sides of a pcb. You have to connect the parallel caps with something, either pcb traces or wires. Sooner or later the pcb trace/wire inductance and resistance outweighs the gains in reduced inductance and ESR won by paralleling the caps in the first place.

If, for example, I wanted a 10,000uF cap, I'd limit it to 4 or 6 x 2,200 uF mounted on both sides of a pcb. Always use higher voltage rated caps - they have lower ESR to start with.
 

Gopher

Member
2005-11-25 12:09 pm
UK
It's not as simple as just paralleling them.

The caps can only be placed a minimum of their diameter and a bit apart unless you mount them on both sides of a pcb. You have to connect the parallel caps with something, either pcb traces or wires. Sooner or later the pcb trace/wire inductance and resistance outweighs the gains in reduced inductance and ESR won by paralleling the caps in the firstplace.

If, for example, I wanted a 10,000uF cap, I'd limit it to 4 or 6 x 2,200 uF mounted on both sides of a pcb. Always use higher voltage rated caps - they have lower ESR ro start with.