Electrolytic capacitors inferior?


I was skimming the reviews of the Oppo 103 on Amazon and came across an interesting 1 star (negative) review.

The first interesting feature of the review was that the reviewer had not actually purchased the Oppo 103 or even heard someone else’s unit. He had considered buying one but decided not to after reading an earlier negative review on Amazon about quality control problems (the earlier reviewer had to return two units before he got a third one that worked correctly).

The second interesting feature of the non-purchaser’s review was that, after he decided not to purchase the Oppo, he examined a photo of the inside of the unit in the Amazon product description and discovered that the unit used electrolytic capacitors, which he considered inferior. He had this to say:

“Why on earth wouldn't the company use solid capacitors on the circuit board? I thought that within recent times all high end equipment frowns on the use of those old school and problem prone electrolytic capacitors as they have developed a notorious reputation for spawning all sorts of device malfunctions.”

Not knowing much of anything about capacitors, other than they can store electricity and reject DC, I search the forums at Audiogon and read a little at Wikipedia. It seems that electrolytic caps: can last anywhere from 5-20 years; can sound different from manufacturer to manufacturer; usually contain a liquid electrolyte but can have a solid polymer electrolyte; are less expensive than film capacitors.

All the discussions about capacitors on Audigon related to amps and pre-amps - no mention of their use in sources like a disc player.

As a result of all of this, I’m interested in any answers you have to the following questions:

1. Does an electrolytic capacitor last longer in a low power device like a player than it does is in an amp? Please disregard the possibility that the player may be obsolete before the caps need to be replaced.

2. Do electrolytic capacitors malfunction, as opposed to dying, more often than other types of capacitors?

3. In what way can the choice of capacitor, as to either construction or manufacturer, make a difference in the sound of a player? Would an electrolytic capacitor produce inferior sound compared to some other type of capacitor? How about when used in higher power devices like amplifiers?

4. VH Audio sells V-Cap copper foil-fluoropolymer capacitors for some amazing prices. What's the cost range for electrolytic capacitors?

5. Is Oppo’s use of electrolytic capacitors in the 103 unusual for a better quality DVD player? Put another way, is Oppo cheaping out or is the Amazon reviewer just being picky? As an aside, the cost a few V-caps equals the retail price of the Oppo 103, but maybe there are cheaper alternatives for non-electrolytic capacitors.
dougmc

Showing 1 response by kijanki

Dougmc, Life of electrolytic cap is a function of temperature. At room temperature they last 50+ years cut by half for every 10degC temperature increase. It is simply drying of electrolyte. The other factor is design that doesn't overstress them (max ripple current) and finally time they are left unpowered since without voltage present electrolyte eats-out dielectric (aluminum oxide) lowering breakdown voltage.

Electrolytic cap in power supply can affect sound in power amps because of their inductance and serial resistance (ESR) especially with large variations of current (class AB). Preamps, DVD players etc. are operating at low constant power supply current and low temperature where electrolytic caps are fine. They are used practically everywhere and if reliability would be an issue we would have massive failures in mass produced electronics.