Classic Hifi Care

I am considering investing in an ESR meter to measure
the functional state of electrolytic caps.

Does anyone here use them, and how useful can they be ?

Any particular models that are good/reasonably priced ?

Thanks !

That's something I think I might use, and awhile back someone was talking about them but right now I can't remember who.

Bill

I'm not much on ESR. It is something to impress people by using big words, but what actually benefit is it? You figure when you get an old device it needs one of everything. I figure it is one more piece of test equipment that will set around in the way seeing limited use and having limited benefit to me. I just replace the caps then move on. I figure if you take the time to test them and find them bad, you have just wasted that time, with the result being the same as if you shotgunned the caps and moved on. But that's just me....

There's always the curiosity factor, finding out which ones are good and which are bad. When we hear a loud hum, we have good indication, but sometimes get nervous about experimenting that way--better not to plug in a device of unknown function.

Chris Campbell

There are many variations in these but I use a Peak ESR70, a video below. (https://www.bing.com/videos/riverview/r ... &FORM=VIRE). Not ruggedized for travel but very helpful on bench finding bad small value caps in circuit. Speed is the key word, method is simple and so are readings. Many others look like overkill.

Crossover caps often measure higher capacitance than marked because of the breakdown of dielectric, reducing spacing between "plates". This can spell trouble for high-frequency cone-type and horn tweeters. Conversely, as the dielectric dries out, lowering capacitance and increasing impedance at the test frequency of the ESR, capacitors take on the undesirable characteristics of resistors and limit current flow.

Electrolytic caps are easy to check out of circuit for LEAKAGE using an EICO 950 or Sprague capacitor tester, which outputs 10-400 volts and indicates with an electron ray indicator (eye) tube. This type of tester uses a "bridge" circuit to read capacitance, also accurate. An ESR tester will not really flag a leaky cap, as its test voltage is too low. Instead, it will display In-circuit/Leaky which literally means you must take it out of circuit to get an accurate reading.

ESR will give you a quick look at the resistance inside a cap, but will not tell you what life is left in it , for that you need to apply voltage .... a 50 year old cap could check fine and a week later explodes ....Personally I don't mess with any electrolytic cap 40 years or older...they get the heave ho instantly no check no nothing just pull and replace. I have the Bob Parker blue ESR meter , that one you gotta build it yourself.... works pretty good and is a great lo ohms meter