600V Capacitor

[J Luth]

Does anyone have an opinion or experience with these caps.
Available in 22uF and 30uF at 600V from what I have seen.
Made by MIEC from what I have found. I had one here last year and if I remember correctly they don't appear to any bigger than a 22uF or 30uF 500V.
Fliptops and other suppliers are selling them.
I have an amp that could use one but I am a bit skeptical about it.
I could use 2-40 350V in series with balance resistors but it would be a lot of work and they may not fit in the location.

[Mick Bailey]

I've used a lot of these over a good number of years and have not had a single complaint or any issue whatsoever. I've done many full recaps of Fender amps with this brand/series. They used to be inexpensive, but as they've become more popular the price has increased substantially here in the UK.

[mozz]

Most of the electrolytics he sells are MIEC brand. From what i asked him, they are very reliable.
https://www.justradios.com/cart.html

[DrGonz78]

As I recall MIEC, according to a website, it was used in NASA projects. Something like that anyway. I used them in a 1962 Fender Bassman. Definitely those amp sit right near 500v. No way was I gonna put in a 500v cap of any brand in there. I have no way of knowing how it held up since it’s been sold. I’m betting after 4-5 years they are just fine.

[DrGonz78]

Well no wonder I remembered reading it. It’s our guy!

[Tom Phillips]

Interesting.
I had never heard of MIEC Capacitors. A Google search found no manufacturer's site but it also did not find any bad reviews.
There was a little more info on the following web pages
https://www.justradios.com/axialelectrolytics.html
https://www.justradios.com/capsize.html
Many suppliers are offering MIEC caps and I suspect that they are the source for house brands sold by many parts suppliers. It's always been a mystery to me when parts do not include a manufacturers name or distinctive logo.

[Mick Bailey]

I bought quite a few of these from Nick B (Black Magic amps). Nick posted quite a bit here at one time and is a highly regarded engineer, so anything he sells should be good enough for anyone. I see he retired in 2022.

[stokes]

"It's always been a mystery to me when parts do not include a manufacturers name or distinctive logo." Usualy indicative of an asian manufacturer that make these caps then get branded by individuals that market them.

[J Luth]

Thanks for the replies.
My main concern is the 600V rating for such a small capacitor.

[tedmich]

the equations used for capacitor longevity usually include operating voltage pulse current, ambient temp etc.
As such a 12,000h 500v cap can often be used at 600v for a length of time (maybe considerably ) less than 12k hours. This is the reason many Mesa amps didnt explode in their first week, with overvolted caps right from the factory

The math works out better for caps run undervoltage (or under temp) but there is no magic tech for 600V vs 500v rated EL caps I think.
Will a 300V rated 10,000h cap run 5k hours at 600V? Probably NOT! Caveat emptor!

[Leo_Gnardo]

Thanks for the replies.
My main concern is the 600V rating for such a small capacitor.

That is why I also hesitate to purchase them. When faced with a situation that would strain a 500V cap or is clearly beyond it, and want to avoid series connections, instead I opt for film capacitors. The only problem I encounter with them is how to mount in the chassis. Carr has been using Solens as long as I've known about them so 25+ year now. Super reliable. They do take up a lot of space though, cylinders clearly bigger than their electrolytic equivalents. I scored a score or two of Panasonic and TDK caps a few years back, rated at 800 and 900 volts. Zowie! Won't be challenging that rating with our poxy little guitar amps will we, should make for even better reliability. But those are rectangular and you have to work out some sort of clamp arrangement to hold them in place. I've mounted them in the back corners of tough old Ampegs like V4, VT40 and B25, adding a schmear of epoxy to each side so there's extremely small probability of them working loose. How ya gonna remove 'em LG when they go bad??? Heh heh, reliability on these is likely to far outlast the amp or anyone's need for it in the far flung future. I regard them as forever components.

One safety mention about film caps. Unlike electrolytics which eventually lose their charge, some over minutes, others over weeks it seems, film caps will hold a charge more or less indefinitely. It may be a good practice to install a bleeder resistor, cheap insurance in case you open up the amp and probe around inside without doing the recommended safety spark, shorting the HT to ground before going in just to make sure. Sometimes I've forgotten, and received another reminder to don't forget.

Sourced the film caps from Newark Electronics nearly 10 years ago. At the time they had some advantageous closeout prices on lots of attractive capacitors and anything else you might dream of. IIRC the ones I got were dirt cheap, about 5 or 6 bucks each. Helluva deal for a helluva cap.

[g1]

Compare size to a radial and you will see that axial are often substantially larger than necessary. For 500V, the Miec is about 1/2 inch longer than some radials. So I don't doubt the technology as far as fitting a 600V in the same size as their 500V.
However, you may run into problems with thinner leads, or total length of the part (including leads) if you need to span a distance designed for old-tech longer parts.

[dai h.]

found some info on a Japanese site. Apparently MIEC is "Ling In Electronics" (Taiwan).

(old dead link archived in wayback machine) :

https://web.archive.org/web/20040606....miec-cap.com/

(this seems to be the current website) :

https://www.miec-cap.com/

Also "Unicon" (apparently a Japanese company with factories in Taiwan and PRC)

http://www.unielecs.com/

https://www.hificollective.co.uk/com..._psu_caps.html

make higher voltage (450, 500V) axials plus the chassis-mounted type in Marshalls (the specs don't look especially good 85 deg C 1000 hours for those)

[garytoosweet]

MIEC have been discussed a few times on the board.

Here's my post from a couple years a go with some decent info: https://music-electronics-forum.com/...157#post973157

I personally don't use them. If I am being honest, it is probably because I am prejudiced as they look like many cheap generic poor quality capacitors. Even though all signs point to them being good quality, I just couldn't feel solid about putting them in a nice vintage amp.

[Chuck H]

The search for good high voltage axials is always ongoing. If someone is doing repairs, providing kits or building a clone I guess it's important. Like a lot of others here I've switched to radial caps simply because there are more options and it's easier to get specs most of the time. The diy hifi guys actually made the switch first and seem to prefer the Nichicon or Panasonic capacitors. Niether rated for 600V though so a totem pole would necessary. But this is a little easier to do with these brands because they're a good bit smaller than the high voltage vintage caps being replaced most of the time.