ESR Electrolytic Capacitors

[teknoman2]

Does ESR of electrolytic capacitors affect
the general performance of any pedal?

I never measure electrolytic caps for ESR cause I dont have any ESR measurement equipment,
Do you think that should I buy better quality caps ex. Frolyt?

Usually I buy everything from Tayda and I believe they aren't the best quality ever.

Any thoughts?

[stecykmi]

just to define what we're talking about, ESR stands for equivalent series resistance and is basically some DC resistance, measured in ohms, that is in series with the capacitance. all caps have some, however it's very small for most caps (smaller film/ceramic/etc), and is usually only a concern with electrolytics where the resistance can sometimes be measured in (low) 10's of ohms.

i would say no in most cases, mostly because they are rarely used in a configuration that makes the circuit sensitive to ESR. power supply filtering and all-pass DC blocking caps, two of the most common uses, aren't sensitive to ESR simply because the values used are so high that they defeat the effects of the ESR. using electrolytics to filter feedback (for delays / for amplifiers) or to generate a clock (if frequency stability is important) would be poor use for this type of cap.

i would say the main advantage in buying good caps is the lifetime of the electrolytic material. RG Keen mentions 10 years as the lifetime of electros before they degrade and float out of spec. one would assume a good quality cap would last longer, although i haven't done research (and haven't been doing electronics long enough for 1st hand evidence, haha) to confirm.

on a side note, in high quality power supplies, such as DC-DC converters for CPU power supplies where response time is very important, you'll often see many electros in parallel to help defeat the ESR of these caps. you'll remember when placed in parallel, capacitance increases while resistance decrease, both good things! the design of CPU power supplies is actually very intense, the current draw can spike upwards of 100A! only for microseconds of time, however the fact that we can achieve response times that fast is amazing, imho.