Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Willabe on October 27, 2015, 07:19:12 pm
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I'm testing coupling caps for tone and 1 of the caps is a SoZo blue molded cap. It sounded thin compared to other caps I'm testing.
On the SoZo web site 1 of the things he say's is;
"It will take up to 100 hours of break in for the capacitor to operate to its full potential. The dielectric will polarize and develop a pattern creating a clearer, full frequency sound."
So I talked with a friend from church today that's a chemistry PHD who worked for chemical companies over the years and taught college. He also plays a little guitar and has played with electronics since he was a kid, he dad was a Ham and started to teach him about tube stuff.
Anyway he said all polymers have so many parts per million of metals in them. He said he worked on projects where they were researching changing the strength of polymers by putting a dc charge on them and adding some heat to realign the PPM metals random charges. Then they had to let the polymer cool under a controlled environment. If done right the PPM metals would stay aligned.
So he said it could be true about breaking in CC to change their tone. He also said the cap might need some heat for the change to happen. Said maybe in a tube amp with signal flowing through the circuit the CC might heat up a little?
I brought up about breaking in new speakers using a 6.3v PT and asked if that might work for the CC's. He said to just connect the CC across the 2/6.3v secondary wires and leave it for a day or so and then test it for any sound change on my bread board rig.
He said it might break in in less time because of the low frequency applied to the cap. But is it enough signal flowing through the cap this way?
Caps are used across AC lines as filters so I think it's safe?
Would be way less expensive then running the cap in an amp with a CD player looped into the input for 100 hours.
Any thoughts? :think1: I don't want to burn down the house.
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I'm pretty sure I would want to place a series current-limiting resistor, eg; 6.3 volts / 10 mils = 6.3K ohms; I'd probably start with 18K or 22K.
Do you have a cap measuring meter or any idea as to how you might measure "before" and "after" whatever process you derive?
If you current-limit it, you'll not be burning down the house. Nobody can say whether the process will work.
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My meter can test caps. But it's if I will hear anything different in tone when I put that cap back in my bread board set up with a Champ 5F1.
I will be able to hear quickly if the cap fattened up in sound against the other 9 caps I have wired to the rotary switch on the BB.
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I'm pretty sure I would want to place a series current-limiting resistor, eg; 6.3 volts / 10 mils = 6.3K ohms; I'd probably start with 18K or 22K.
If you current-limit it, you'll not be burning down the house.
Ok, thanks. :icon_biggrin:
But what power rating?
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P =E * I (hopefully for AC also?) Eleventeen picked 10milliamps so 6.3*.01 = .063watts?
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You don't need any resistors. You need to apply the capacitive reactance equation.
Xc = 1/(2*pi*f*C) where f is in Hertz and C is in farads.
Since f will always be 60Hz, this can be simplified as Xc = 1/(377*C)
So, a 1µF cap has a reactance of 2653Ω. A .047µF cap has a reactance of 56.4KΩ. A 250pF cap has a reactance of 10.6MΩ.
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So the capacitive reactance will limit the PT by it self?
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Yes. A 1µF cap looks like a 2653Ω resistor to 60Hz. Smaller value caps look like an even bigger resistor. Xc is inversely proportional to frequency.
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Ok, thank you. :icon_biggrin:
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I would think HIGHER frequency would be more excitement per day.
However 60Hz is so much cheaper than any other that it is probably the way to go.
I'm not a real fan of breaking-in passive parts. If it "sounds thin" then it is defective. If it sounds different in a week, it is unstable, or your ear has acclimated.
Speakers do break-in, and I always favored doing this with the *same* complex waves as it would have to handle for a living. At home I played what I liked. At work (music school) I played various Great Composers. So if I really wanted to shake-up caps or other parts, I would favor the tape-loop technique. (Or radio (maybe innernet) from an appropriate station, to get a mix of different stuff {except here in Maine, where we may hear the same few songs day after day}).
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I think the speaker breaking in deal is just to loosen up the new and stiff cone and spider?
I have seen people play bass notes through them to do this
Don't know how well that works, just what I have heard :icon_biggrin:
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Do I need to bother even hooking up a CT?
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Do I need to bother even hooking up a CT?
No. But this is your test. AFAIK there is no 'standard' to follow.
I have to agree with PRR on this stuff. Breaking in a coupling cap just sounds like snake oil to me. :wink: But I'm still interested to hear what you find out.
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I have to agree with PRR on this stuff. Breaking in a coupling cap just sounds like snake oil to me. :wink:
I'm going to try and find out what's what here. :dontknow:
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Breaking in a coupling cap just sounds like snake oil to me. :wink:
Meee tooo
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I think the speaker breaking in deal is just to loosen up the new and stiff cone and spider?
I have seen people play bass notes through them to do this
Don't know how well that works, just what I have heard :icon_biggrin:
Avatar sells a couple of Celestion models (V30 and G12H30) that are broken in before they ship them. They connect the speakers to an audio source and play bass heavy music through them overnight. Turn in on when they leave for the day and shut it down when they arrive the next day. It does save you the time of doing that. I bought a quad of Reaper 30 speakers from WGS and they were a bit fizzy when I first bought them but that faded as I played them. I have read about some folks hooking up a 6.3VAC heater transformer to a speaker to break it in. Seems like that would annoy me in about 30 seconds.
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I made on of those speaker breakin things a few year ago from a dead reverb pan. I rarely use it because it is so annoying. At the time i had a few 1960 Alnico speakers that were very tight and i tried breaking them in to loosen them up. It worked for a while but with old tight Jensens they simply needed to be re-coned. It does loosen up the spider and cone of new speakers real nicely. If you can take the constant hum for hours. I finally decided to place a speaker outside under a bench and forget about it for 24 hours or more. Never in the house though.
It would drive you insane.