All styrene caps in a Concorde

[azatplayer]

I built this COncorde clone some time ago and have had the most problems ive ever had in a build, that is it was only one problem, but the most trouble shooting ive had to do. Very very frustrating.
I used all sozos in it, and part of my diagnosing was to rip out caps and try others, well in the midst of the fix, and it wasnt the sozos, i tried some styrene caps on the power tube grids.
Was subtle, but i liked the change.
So i capped the whole amp with them. Instant change from doing the tonestack caps was a prettier topend, more pronounced highs.
Chimey. QUite nice. Will give it a few days and see if i love it or not.

[Cliff Schecht]

I love polystyrenes and promote their use often. I've got them in a large range of values up to 0.0022uF (I switch to PIO for the bigger stuff) and would take them over mica/ceramic caps any day. The beauty of them is they add no coloration whatsoever. What you hear is the circuit/speaker/tube choice doing the voicing, not the passives that are really just there to put the tubes in a "proper" operating environment.

They usually come in 1-5% tolerance (mine are mostly 1-2%), have a super duper low variance/drift over temperature and are overall very stable caps in general. The polystyrene material makes an amazing dielectric because it's so immune to changes in temperature, humidity and such. These guys used to be used very often in tuning/timing circuits for radio equipment because at the time they were the best caps available as far as accuracy is concerned. Old Tek scopes and other high end equipment will use these caps everywhere. Nowadays it's been superseded by teflon caps but I don't bother with these, they are quite costly and frankly overkill for what we need. I got my caps super cheap, if you look around at hamfests and electronics swap meets you might luck out (even eBay if you are patient).

The one thing to watch out for is the polystyrene is extraordinarily easy to melt with a soldering iron. I've ruined so many of these it isn't funny. You have to really plan for what angle you are going to come in with the iron before applying heat. Anything past a few seconds and you will melt away the styrene and short the plates together. A lot of people turn their irons way down and heatsink the leads, but I find this to leave an unsatisfactory solder joint and I don't like clipping stuff on the hair thin leads that these caps usually have. I actually go for really high temp on the iron (750-850) and leave a bit of lead coming out of the part. If you're quick you won't melt the cap at all, but it takes some practice before you stop melting them. If you do this right the part you are soldering the cap to will act as a momentary heatsink (especially pot lugs or turrets). Eyelets aren't very polystyrene friendly because of how hot you have to get them to fill it up with solder so on these, I usually heatsink the leads.

[azatplayer]

Thats good stuff Cliff. Yeah ive been using them in the small stuff for ages, love paper caps too, specially the K40Y-9's.
I found a bunch of bigger value styrenes @ 600V, had to grab em to see what they were like. .022, .047 and .1. The values we need most. Real big leads on them. Pretty happy with th result. Been playing with them for a couple hours in this amp, and i will say they have much clearer tone than the plastic caps that i was using. The highs have a shimmer that wasnt present and the lows have a little kinda tighter punch, in fact maybe that shows the other caps had a more present midrange?
I like em sofar, was surprised to see them in these bigger values.

[Cliff Schecht]

They did put these in different packages but I don't know about who did what and when. I came into the electronics biz after styrenes were phased out, so most of what I know comes from my dad or older analog designers who dealt with high precision circuits.

I only use the jellybean looking caps, I don't know what they look like aside from this and a few semi-distinct plastic shells. Google images shows lots of examples of different versions but I tend to not recognize these immediately as styrenes unless they are marked as pretty high voltage for the size/shape.

OTOH I know the clear guys I have are not only styrenes (with a clearly and correctly marked outer foil!) but are very high precision parts so I tend to only use these in my amps. I have bags upon bags full of caps that I'm not certain on the technology, not much in the way of HV (found a nice stash of micas) but there are probably some smaller styrene variants that would be good for pedals and such. I need to look into this more..

[martin manning]

nevermind

[diagrammatiks]

love styrenes.

agree with cliff on destroying them.

i've destroyed so many.

especially the tiny pf value ones.

there's a graveyard of half melted 470pfs in my trashcan.

[renshen1957]

They did put these in different packages but I don't know about who did what and when. I came into the electronics biz after styrenes were phased out, so most of what I know comes from my dad or older analog designers who dealt with high precision circuits.



OTOH I know the clear guys I have are not only styrenes (with a clearly and correctly marked outer foil!) but are very high precision parts so I tend to only use these in my amps. I have bags upon bags full of caps that I'm not certain on the technology, not much in the way of HV (found a nice stash of micas) but there are probably some smaller styrene variants that would be good for pedals and such. I need to look into this more..

and

I found a bunch of bigger value styrenes @ 600V, had to grab em to see what they were like. .022, .047 and .1. The values we need most. Real big leads on them. Pretty happy with th result. Been playing with them for a couple hours in this amp, and i will say they have much clearer tone than the plastic caps that i was using. The highs have a shimmer that wasnt present and the lows have a little kinda tighter punch, in fact maybe that shows the other caps had a more present midrange?
I like em sofar, was surprised to see them in these bigger values.

Hi,

The original Vox AC30/4 had Wima styrenes for caps (before the philips/mullard mustards).

Check out

http://www.justradios.com/orderform.html has Polystyrene caps 630V with values from 10pf to .010 uf (10nf for the rest of the world)

I have scored polystyrene in higher values from time to time on ebay.com

Best Regards,

Steve

[rsalinger]

I capped the whole amp with them. Instant change from doing the tonestack caps was a prettier topend, more pronounced highs.
Chimey. QUite nice. Will give it a few days and see if i love it or not.

What brand did you use?

Cheers,
Rpb

[azatplayer]

Paktron i believe is the name of them, tho there is nothing on them.
Old caps from days gone by
Oh yeah, theyre ITW make.

[Mark]

I've seen a copper panel AC-30 (Albion transformers) with polystyrene cap, they were Wima's.

I though Sozo were going to sell polystyrene caps, but it all seems to have faded away.