Lemco silver mica voltage rating

[whopperplate]

I purchased these Lemco 470 p csilver mica capacitors hoping they are rated at the corrected voltage but there is no marking. Seem a little smaller than the ones in marshalls. What y'all think? Thanks

[coldengray]

Probably 350v. Post some pics and hopefully Neil will chime in. He will know.

[Tazin]

I think the typical working voltages were: 350vdc, 500vdc, 750vdc, and 1000vdc. The 750v and 1000v had thicker leads. As for physical size, it varied depending on voltage rating and tolerance. A 1% and 2% tolerance cap was larger in size compared to a 5% or 10% cap.

[whopperplate]

Thanks guys, sorry I thought I posted a pic but apparently this is a thing: "Sorry, the board attachment quota has been reached". Here's the eBay link:

http://www.ebay.com/itm/182157314364?_t ... EBIDX%3AIT

They are marked 1%. About the width of a penny and slighlty thicker.

Thank you all

[Tazin]

They appear to be pretty far out of tolerance according to the sellers measurements. Some Lemco's have a voltage rating stamped on the back which the seller didn't post pictures of. Tough to tell from the picture which voltage these ones are, but I don't think they are 1000Vdc....Perhaps Neil might have a better insight.

[whopperplate]

Thank you, I hope at least they are able to withstand the 1987voltages, crossing fingers. No markings on the backside.

[neikeel]

Think they are 350v rating ones (bit smaller than the 500v ones)

They should be fine on your mixers and probably ok in a 50w tone stack, not so good in a 45/100 or early 70s Superlead.

[whopperplate]

Thanks boss, very much appreciated.

[danman]

Be sure to use a heatsink when soldering them. I have read several times lately of people having problems with noisy silver micas. It seems that they are easily damaged from overheating when soldering. I have never had an issue but using a heatsink is good insurance to prevent damage. http://www.thegearpage.net/board/index. ... t-22093134

[whopperplate]

Thanks for the tip, got my heat sink, will do!

[RockinRocket]

Think they are 350v rating ones (bit smaller than the 500v ones)

They should be fine on your mixers and probably ok in a 50w tone stack, not so good in a 45/100 or early 70s Superlead.

Hmm there cant really be that much voltage on the cathode follower. 160ish on a 50w. Whats the cathode followers voltage on those amps?

[whopperplate]

The 470p will see about 250 off of v2 in a 50 watt.

[RockinRocket]

Metro build gude shows about 150 on 50watts and 170 on SLs.

[whopperplate]

No, the 470p is off of pin 6. Plate voltage of 270 according to metro chart

[RockinRocket]

No the tone stack is off the cathode Pin 8. Not the plate pin 6.. unless your not building a 1987?