ESR Meter

[Strelok]

Hello all you Creationari_istos!



The wheather here now is much better to create things!


What is your experience with ESR meters?
Are they any good?
They sound to good to be true


So, you can only use them on discharged caps.
When does the voltage rating come into play, is that just a thing to get the right result?


I saw the famous Blue ESR Meter by Anatek, it is stated to measure up to 450 Volts.
Then there is the MESR-100, I don't know what the max rating is of that one.
Is it a problem if it "stops at 250 V"?


The "Blue" seems to be not so good available anymore.
I don't like Amazon but paying $50 shipping when ordering direct is a bit too steep for me.

Neither have reference charts that go above 250 Volts.
So someone suggested to measure a good cap and keep that figure for reference.

Another someone created a frint end to use with a normal multimeter.
The big advantage is the protection circuit if you measure a cap that is still charged by mistake.

What do you use?




Strelok

[K O'Connor]

Hi Strelok

I believe you will find that almost no one uses ESR meters, l;east of all for MI.

ESR - equivalent series resistance
DF - dissipation factor
DA - dielectric absorption

These are all capacitor imperfections, of which, electrolytic capacitors suffer the most. ESR is only one factor and all three will "go crazy" after a few years and adversely effect audio performance. These imperfections contribute to the sound of vintage amps and some techs and amp builders prefer to mimic the effect by using series caps in new builds where a single cap could easily sustain the voltage. TUT3 Vox chapter shows a way to erode the cap performance in a controlled way (the cap itself is uneffected).

ESR effects both charging and discharging of the cap. TUT3 shows how to limit the charging current surges to protect the PT and the cap, without altering the low-impedance the audio circuit requires from the supply.

In general, the service life of an electrolytic cap is 14 years, as TUT state - that is, if you want their lowest-distortion performance. Regular application of voltage will keep the caps healthy and the amp tone consistent for a longer period of time than will transient use of the amp. This is a good reason to avoid collecting amps. Just find one or build one that is your daily amp.

The easiest fix is to either change the caps if they are suspect or to add a plastic cap in parallel to correct the high-frequency effects of the main filter.

As a cathode bypass, an electrolytic has a particular sound, where poly caps do not.

have fun

[Strelok]

Hi Kevin!

Now what do do you know, they are indeed to good to be true!
It seemed handy to me to fnd out which cap was doing strange things.

Thanks for the explanation!

Fantastic that other builders can read this too here!

Haha yeah, "going crazy", I remember you said that about ESR.
I saw a video on a repair channel in YouTube and the guy was using an ESR meter, then I remembered it.

Thank you for everything!


Strelok

[Champ81]

I seems that esr is only one factor.  In that case would it be worthwhile in any way to invest in one? 
They have this which is not cheap. I believe it tests capacitors in circuit. 

https://www.howardelectronics.com/specia...ter-cap1b/

[K O'Connor]

Hi Guys

I already made my view clear and personally will never buy an ESR meter.

Guys dealing with antique amps and equipment may wish to try to use what is there BUT you are dealing with parts that are seriously fatigued and should be cut out of the circuit. Cans can be left in place for the vintage look, with small modern caps inside the chassis wired in their place.

Paper dielectric caps are not really capacitors after a decade and need to be replaced by polys.