Coupling Cap

[Diyengineer]

Hi,

I've recently seen a design where electrolytic caps were used as coupling caps in some places. Are these ok to replace with film caps? I always thought film caps were supposed top be better for coupling purposes where electrolytic caps are more for power supply filtering where larger values are needed.

Thanks

 

[Koifarm]

Electrolytic caps are used for ages as coupling caps. I have seen them in Hypex, shanling, mcintosh, philips equipment. Mostly used when they need big (> 10uf) values. Replacing with film caps is sure possible but will not always give better sound/specs.

 

[rayma]

I've recently seen a design where electrolytic caps were used as coupling caps in some places. Are these ok
to replace with film caps? I always thought film caps were supposed top be better for coupling purposes
where electrolytic caps are more for power supply filtering where larger values are needed.

Various people use one or the other for different reasons. There is an "objectivist" view that if the cap
is large enough, it won't have a sound, so they use electrolytc caps for coupling maybe ten times the
value that would be used for a film coupling cap.

If you have the room and an adequate voltage rating, film types are fine for coupling, though usually
more expensive (but they will last indefinitely, unlike electrolytics). Use noninductve types if possible.

If long-term reliability is important to you, use as few electrolytics as possible. For those that you
must use, get 105C and a higher voltage rating than needed, to increase the reliability and lifetime.

 

[egellings]

Film cap is fine for coupling, but their size make make them hard to physically fit into the location where the old 'lytic was.

 

[Diyengineer]

Thanks guys, they are using 1uF electrolyics for the caps in question, so I think I might just switch to film then since room isn’t an issue.