Stocking electrolytic capacitors

[RiRaRi]

Hello. I work on and repair vintage boomboxes and non–high-end audio solid-state gear from 70s and 80s. Mostly, electrolytic capacitors are still good, and the problems are in other components. However, since I’m buying something else anyway, I would like to build a small stock of common values so I have them on hand. I live in a remote area and can’t get good-quality capacitors quickly. I want reliable, good-quality caps, but not audiophile high-end ones.

Since many capacitor series are being discontinued, I’d like to ask for recommendations of well-stocked series suitable for different stages. I will also include my previous list, but as I mentioned, a lot of the capacitors in it are discontinued.Any advice is very welcomed.

[BILLPOD]

Good Morning RiRaRi,  Here is an assortment that looks handy: https://www.amazon.com/ALLECIN-Electrolytic-Capacitor-Assortment-Kit/dp/B0C1VBXCQM/ref=sr_1_22?
There are quite a few other assortments on Amazon.

[RiRaRi]

Thank you for your comment, however i would like to buy capacitors from reputable brands.

[Randy222]

Look to Mod and F&T brand caps.

Used a lot for fixing/upgrading guitar amps and such.

[nctnico]

Thank you for your comment, however i would like to buy capacitors from reputable brands.

That is a good idea. I think the list with values is OK for most repairs. You could go to Panasonic and Nichicon's websites to check which series they recommend for certain applications in case the listed series are no longer available. Typically I use Panasonic electrolytics in many of my designs (or replacements if I need to repair something).

[iet]

These are also good brands: Rubycon, Nippon Chemi-Con.

[dietert1]

I would consider using film caps for values up to 2.2 uF. Those small electrolytes are the ones getting dry first. The stock should not be more than a year or so. Otherwise you will be using "new old stock", which isn't the best idea with electrolytic caps.

Regards, Dieter

[iet]

There's an interesting thing about 1-10 uF electrolytic capacitors. After many years of use, the capacitance may be within the tolerance, but the ESR can vary significantly.

[mariush]

Buy low impedance series, but avoid the ultra low impedance ones unless they're used in switching power suppy type circuits - these "ultra low impedance/esr" series can have esr too low which could affect circuits that expect some ESR for stability.

For example

Rubycon :  https://www.rubycon.co.jp/en/products/al-radial-lead/series (scroll down for the chart)

Standard (replace 85c rated ones with this)  PX series.

Low impedance : YXJ , YXF, ZL* (ZLH, ZLJ)  ...ZLG is considered very low impedance, good for switching power supplies but could be too low esr for some circuits

Chemicon : https://www.chemi-con.co.jp/en/products/aluminum/chart/  (scroll down to radial electrolytic)

KMQ to replace standard 85c capacitors

KZE, KY / KYA, LXZ, LXY for low impedance, more modern  , lzg for super low impedance.


Nichicon  : https://www.nichicon.co.jp/english/_assets/images/products/catalog/corporate/digital/chart_E.pdf

Page 3 (37 in PDF) for the radial electrolytic

VZ,RZ, VY for 85c capacitor replacement

PW as older lowish impedance (but quite high compared to more modern series), sort of comparable with Panasonic FC series 
PS, PJ for lower impedance, HW and HE for very low ESR (comparable to panasonic fm/fr , rubycon lzg etc)


From Panasonic  ... FC is older series (has good reputation for audio circuits), FM and FR are more modern very low impedance, from what I heard FR is based on a semi-liquid type of electrolyte while FM is more water based electrolyte , so FR is not always better than FM when it comes to ESR but it can last longer.
 
For distributors .. digikey, mouser, newark/farnell, rs components, tme.eu in europe, LCSC.com in Asia


PS also if you have devices with known problems due to capacitor placement near very hot heatsinks, you may want to check out series like Rubycon RX30 - they're low impedance series rated for 130c - they're not super low impedance but it most likely won't matter for the devices you're fixing.

[nctnico]

There's an interesting thing about 1-10 uF electrolytic capacitors. After many years of use, the capacitance may be within the tolerance, but the ESR can vary significantly.

That greatly depends on the amount of abuse a capacitor sees. Heat is enemy number one of an electrolytic either through high ripple current (self heating) or external heat. An electrolytic capacitor which is kept cool can last for many decades.

[dietert1]

In the context of self heating by ripple current we should also mention polymer caps as another option. Great parts if you want low ESR.

Regards, Dieter

[Siwastaja]

There's an interesting thing about 1-10 uF electrolytic capacitors. After many years of use, the capacitance may be within the tolerance, but the ESR can vary significantly.

That greatly depends on the amount of abuse a capacitor sees. Heat is enemy number one of an electrolytic either through high ripple current (self heating) or external heat. An electrolytic capacitor which is kept cool can last for many decades.

This.

* Not too much external heat - ambient (around the capacitor, not the product case!) ~50degC or less,
* Not too much internal heat - derating of ripple current value
* Decent manufacturer
* Not unlucky (e.g. capacitor plague affecting materials used by everyone including good manufacturers)

-> no lifetime problems. 30 years of lifetime entirely realistic, even if not guaranteed. Many if not most electronic gadgets from 1990's are still fully operational.

Abused capacitors then again can die as quickly as just 1-2 years.

Besides, even film capacitors have had large scale lifetime problems (see RIFA).

[iet]

That greatly depends on the amount of abuse a capacitor sees. Heat is enemy number one of an electrolytic either through high ripple current (self heating) or external heat. An electrolytic capacitor which is kept cool can last for many decades.

These are well-known facts.
The capacitors I mentioned were likely operating poorly for a long time due to the gradual deterioration of their surrounding components. If a capacitor's operating conditions deteriorate, its service life is correspondingly reduced.
I also wanted to emphasize with this example that a capacitance meter alone won't solve such problems. Therefore, manufacturers produce devices that display multiple parameters simultaneously, which is definitely very helpful in such cases.
A simple ESR meter can also be used in such cases if you're familiar with the acceptable values ​​for electrolytic capacitors or by comparing the values ​​with new, tested capacitors.