Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: markmalin on June 09, 2016, 09:27:10 pm
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I'm wondering what the consensus is. If I use a Silver Mica or a Ceramic cap for a treble cap (for example, the 500pf in an AC 30), is one better sounding? I've gone back and forth, for a while I was thinking the Mica caps sounded more musical and the ceramics more harsh...Does anyone have a strong opinion on these or is it six of one, half dozen of the other, so to speak.
Mark
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Below 1,000pFd, NP0 ceramic is as perfect as it gets. Any "tone difference" is the cap color, or price, not its electronic action.
Over 1,000pFd, ceramics increasingly tend to be made of ugly-stuff to get the rated pFd in small space. C varies with voltage, enuff for a critical ear to hear.
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And be aware that NP0 ceramic is one of (at least?) 3 different varieties of ceramic caps.
And if you buy NP0, make sure to check a data sheet for lead length. Many have very short leads (for p.c. board work).
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So you guys don't like the old domino silver mica caps?
I watched a youtube video by mrcarlsonslab (I think),
explaining some of the tolerances of the different caps.
He hated all paper caps, said to remove them all.
Some of the other newer material caps were quite temperature sensitive.
I thought he indicated the old silver mica caps were very temperature stable, and unlikely to leak.
I haven't had any problems with them since I began using them when I got my cheap capacitance testing meter.
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do you buy the NPO ceramics from Digikey? I see Doug doesn't have them, and I don't see them at CE Dist or Mojotone.
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I would use the 500V Silver Mica.
I like the way they look.
I really think there are more productive places to stir the spice.
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That's what I have in there, but here's what's driving this. I'm trying to track down a very intermittent situation where the amp start producing static (popping, sounds like an old radio off station) for maybe 2 minutes and then stops. I was spraying some freeze spray around to see if maybe it was a cold solder joint and when I hit the bright cap (120pf silver mica) it caused the amp to rumble and pop. Maybe normal, but I swapped it with a ceramic I had and it's not as prevalent ...which may be my own idiotic lack of experience...but I hit the mica treble cap and that made the same sound only worse. Hence the idea to swap it out.
Thing is, I'm not sure I like the sound of that particular bright cap
that's the whole story
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Here is a Mouser link to the Ceramics I use. http://www.mouser.com/Passive-Components/Capacitors/_/N-5g7r?P=1z0z7l5&Keyword=npo&FS=True (http://www.mouser.com/Passive-Components/Capacitors/_/N-5g7r?P=1z0z7l5&Keyword=npo&FS=True)
I ran into some problems with Silver Mica caps, However the black ones Doug has are good.
I have read where guys day you must use Silver Mica or you amp will sound harsh and the same person covets a 65 Stock Fender Deluxe. :l2:
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Thanks, Ed. That helps. I may just order a handfull of these and see if I notice any difference.
I have noticed changing ceramics for silver mica has mellowed out a 5E3 build I had, but this particular amp is so bright, so harsh and so hissy if I turn it up loud.
Anyhow, thanks - I'm going to try the NPO's
I'm curious to know more about the issues you had. Was it similar static? Here's the thread to my original issue (not to hijack this one). http://el34world.com/Forum/index.php?topic=20385.msg214615#msg214615 (http://el34world.com/Forum/index.php?topic=20385.msg214615#msg214615)
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Thanks, Ed. That helps. I may just order a handfull of these and see if I notice any difference.
I have noticed changing ceramics for silver mica has mellowed out a 5E3 build I had, but this particular amp is so bright, so harsh and so hissy if I turn it up loud.
Anyhow, thanks - I'm going to try the NPO's
I'm curious to know more about the issues you had. Was it similar static? Here's the thread to my original issue (not to hijack this one). http://el34world.com/Forum/index.php?topic=20385.msg214615#msg214615 (http://el34world.com/Forum/index.php?topic=20385.msg214615#msg214615)
No, not chasing noise. I will use silver mica, but I buy Cornell From Mouser. When I am building a clone circuit, I use what was used in the real amp. Like My AC15, I could not get the exact ones, but I used ceramic.
They are not as heat sensitive to the soldering iron. I can't hear the difference and even for snubbers I prefer ceramic. Tougher and durable and easy to get in high voltages.
A few years back I read an article on how much better Silver Mica sound and I fell for it and bought a lot of them from Weber. Big mistake. They leaked DC and I did not have near the troubleshooting experience then as I do now. Needless to say I kept getting problems. I will say I learned a lot, but the frustration level was high.
I finally realized that all the old amps I have that everyone loves like my 68 Plexi, 65 Deluxe, 62 Bassman.............etc all have ceramic caps in them. I also spent some time studying the caps and there are plenty of ceramics that are audio quality and they are normally cheaper.
I only use Silver Mica if I am replacing one for someone else. Also, I use a lot of Sozo caps because I get them free. :icon_biggrin:
I have pretty good ears too.
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Angela says the old ceramic caps sound better than new production.
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Angela says the old ceramic caps sound better than new production.
Who is Angela and why should we listen to her? :laugh:
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http://www.angela.com/ (http://www.angela.com/)
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I usually use a mix of polystyrene and C0G ceramics. Had a bad experience with some silver mica caps, which turned out to be microphonic, and stopped using them.
Distortion generated by old ceramic caps in an RC filter is severe compared with C0G, and things in an CR filter are much worse, in the neighbourhood of 1% at low frequencies
You might like this distortion for guitar, though. :dontknow: