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TunaFish 9th March 2005 02:07 PM

Computer Grade Cap or Inverter Grade Cap???
Hi all expert,

Anyone can explain what is Computer Grade Cap and Inverter Grade Cap? (Other than used in computer and inverter. )

I know the computer grade cap is more expensive. Some of them are in high voltge (e.g. 450V DC), it doesn't look like used in computer......

I think it may be just 2 grade of cap (obviously higher than ordinary cap).

But what is the specification/range for a cap can be called as computer grade/inverter grade?

Computer Grade is higher or Inverter Grade is higher?

Thank you in advance.

Tuna Fish

peranders 9th March 2005 02:19 PM

The types you mention are heavy duty types for high currents under hard conditions with high reliability and long life time. For that reason they are much bigger than conventional types.

Sch3mat1c 9th March 2005 02:34 PM

Computer grade caps used to be used in computers, the big mainframes of the 50s to 80s. This was before rock-solid tons-of-amps transistors made switching power supplies possible, but the circuits still required the same stable power supply. You can imagine how annoying a 5V at 250A power supply was... :D

Inverter grade caps are made for inverters, obviously, which demand high peak currents. Consider a 10kW inverter running a squarewave through its transformer, that's a good bit of power being switched eh? Something needs to supply, snub or filter that appetite.


TunaFish 10th March 2005 07:53 AM

Thank you for your help.

Does the Computer Grade/Inverter Grade Cap is suitable for Hi Fi use or not?

Computer Grade is higher or Inverter Grade is higher?

Thank you in advance.

Tuna Fish:)

analog_sa 10th March 2005 08:20 AM

Hi TunaFish

I only have experience with computer grade caps and find it difficult to generalise - some of very good and others not. The sound is generally mellow, laid back and very listenable.

jacco vermeulen 10th March 2005 09:30 AM

When you take a look inside a regular inverter you will see Long Life capacitors for 105C.
A CG can handle larger surge values than a LL, 25 % above max is not uncommon. Which explains the huge size of CG's.

imo, the preferred audio electrolytic capacitor is a CG, 105C models if possible, because of the higher surge.
Both are LL versions.
I have been using Siemens/Sepcos Long Life, Sikorels, Roederstein, SifSafco, Mallory CGS.
Sikorels are the absolute best ; LL, +105C, extrem low esr and esl, but 3 times more expensive than regular good quality caps.
The Siemens Sikorel B41550/41570 were intended for very fast switching supplies.
For gain stage powersupplies i used the Sikorel inverter type cap, for an output stage that would mean serious money, there i use CG's

jacco vermeulen 10th March 2005 10:02 AM

2 Attachment(s)
I am just cleaning an inverter, here is a picture of the caps.

Computer Grades are still used for big main frames, that is where i try to buy them from.
An Aluminium electrolytic is an alloy foil with an electrolytic layer on it, the foil is rolled up and and an insulating cap is placed around it.
Computer and inverter grades have a much thicker electrolyte layer, the thicker layer enhances the long term behavior of the caps, and more.
That is why both CG and LL inverter capacitors are much bigger, a CG up to 20 % more than a LL.

andyjevans 10th March 2005 01:45 PM

I went out of my way to buy some Mallory computer grade caps for the first cap in a tube power supply. I hated it - slow, dead sound. I have had better luck with physically small sizes of caps - even fairly cheap axials - in conjunction with chokes.

TunaFish 11th March 2005 05:53 AM

What does the 40/105/56 and 40/85/56 indicated in capacitor means?

I just know the middle number = operating temperature.

How about the 40 and 56??????????????

analog_sa 11th March 2005 06:57 AM


I hated it - slow, dead sound

Same experience with Mallory. SicSafco otoh are exceptional.

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