MIAL Polystyrenes any good?

[JD0x0]

I'm about to pull the trigger on 50 MIAL polystyrenes for a good price. Are these quality caps as far as PS go? I know PS are generally fragile, but I dont want these if they're going to be ticking time bombs ready to fail.

Polystyrene Capacitors
Axial Leads
100pF
160V
5%
5mm x 14mm

Manufactured by: MIAL
Part Number: Type 617.2

Would I be better off paying more to go for a Philips 1% 630V? I dont necessarily need the tighter tolerance, but if they're going to be significantly more reliable, and better quality, I'd probably just spring for them. I'm kind of set on getting some polystyrenes. I've got plenty of Silver Micas on hand.

[John_P_WI]

What's the application? They have a small cap value and voltage rating for tube amps...

[JMFahey]

Why would you mistrust European made Polyerstr capacitors?

Ticking time bombs?

Well, maybe so ... if you think the clock was set for a couple Centuries

[JD0x0]

Why would you mistrust European made Polyerstr capacitors?

Ticking time bombs?

Well, maybe so ... if you think the clock was set for a couple Centuries

I've read about people getting cruddy PS's and fairly frequent failures, but who knows, it's the interwebs. Honestly I dont know anything about MIAL, and a quick Bing search didn't seem to bring up anything useful, thought I'd come here.

What's the application? They have a small cap value and voltage rating for tube amps...

My original intention was to get them for tonestacks, and other applications where there wouldn't be excessive heat or very high voltages on them. For example, they probably wont ever get used as 'snubbing' caps mounted on the tubes.

[Leo_Gnardo]

I'm about to pull the trigger on 50 MIAL polystyrenes for a good price. Are these quality caps as far as PS go? I know PS are generally fragile, but I dont want these if they're going to be ticking time bombs ready to fail.

- - - - -

Would I be better off paying more to go for a Philips 1% 630V? I dont necessarily need the tighter tolerance, but if they're going to be significantly more reliable, and better quality, I'd probably just spring for them. I'm kind of set on getting some polystyrenes. I've got plenty of Silver Micas on hand.

The "fragility" of PS has to do with failure due to overheating when soldering. So use a heat sink clip on the lead as you solder. I use 120 pF PS as bright-switch caps, no problem, sound tends to be clear & bright, not harsh. Haven't used PS in a tone stack but you could try that with the 630V rated ones.

Although silver mica are supposed to be the bees knees, I've had a fail in tone stack use. Rated 500V 250pF and had only 250V on the circuit, went short circus. Had me flummoxed because I had in mind "silver micas just don't go bad." So much for that. Happened only once or twice but it goes to shows ya, they ain't perfect. Just pretty dam' good.

[David Root]

I've used MIAL PS caps, had no problems with them, but I only use 500V or 630V rated PS. It's too easy to slip one into the wrong spot, they're so small.

[JD0x0]

Thanks for the input, everyone. I went with 180pF 630V Philips, to try. The amp I'm trying these in originally had a 220pF PS in the stack, but I swapped it for a 180pF Silver Mica, in the overhaul. Original one was extremely fragile. The highs sound a little 'cold' and harsh at times, more so with overdrive. I'm hoping the PS smooth things out slightly without sacrificing the nice articulation. Plus it'll be nice to have these on hand for other projects. Thanks again. By the way, there's some pretty good deals on ebay, for the NOS Philips Polystyrenes, for anyone interested, because it does seem like these types of caps are getting harder to find and more expensive.

[davent]

You can get 10pF - 10000pF, 630v, 1%, polystyrenes at Justradios.

http://www.justradios.com/cart.html