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Author Topic: burning in capacitors  (Read 7556 times)

breathe

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burning in capacitors
« on: January 10, 2011, 09:38:11 am »

I recently had my 1976-era Kenwood receiver recapped and was initially horrified at the new sound, but after a month's use I'm getting back into it.  Do caps need to have signal passing through them to "burn in" or is just having the device turned on sufficient?

Thanks,
Nicholas


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Jim Williams

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Re: burning in capacitors
« Reply #1 on: January 10, 2011, 01:06:33 pm »

Depends, just like underwear. Caps with a DC bias will break in from the DC. Those without a DC component requires an AC signal.

Whether it's needed, real or imaginary, I leave to you. However, Reliable Capacitors, makers of some of the best film and foil caps including the multistage MIT MultiCaps says their products require a 50 hour break in period for best sonics.
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Jim Williams
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jetbase

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Re: burning in capacitors
« Reply #2 on: January 10, 2011, 05:19:30 pm »

I have "burnt in" new caps by running a tone through the recapped equipment for three days & have noted a big difference in the sound after that period in some cases. Recently I have recapped channels on my console with much higher values, did the same burn in & there was no noticeable difference to my ears (whereas previously with lower value caps I had noticed a significant difference). I guess that if you recap & it sounds a bit harsh afterwards then try burning in.
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Re: burning in capacitors
« Reply #3 on: January 11, 2011, 12:50:30 pm »

Key is after a month's use...  I submit you're probably just becoming accustomed to the sound.  
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Geoff Emerick de Fake

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Re: burning in capacitors
« Reply #4 on: January 11, 2011, 04:47:52 pm »

Absolutely. Ears need a burn-in...
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marcel

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Best, Marcel

Geoff Emerick de Fake

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Re: burning in capacitors
« Reply #6 on: January 12, 2011, 01:18:57 pm »

According to JW in this thread, there are some caps manufacturers who recommend burning-in.
The idea of having to burn-in brand new components makes me rage. If they need burn-in, why didn't the manufacturer do it?
By not doing it, the manufacturer takes the risk that his products are used incorrectly and as a result, be misrepresented.
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mell

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Re: burning in capacitors
« Reply #7 on: January 15, 2011, 04:01:42 pm »

Geoff Emerick de Fake wrote on Wed, 12 January 2011 19:18

According to JW in this thread, there are some caps manufacturers who recommend burning-in.
The idea of having to burn-in brand new components makes me rage. If they need burn-in, why didn't the manufacturer do it?
By not doing it, the manufacturer takes the risk that his products are used incorrectly and as a result, be misrepresented.


burning in 2.000 caps a day? that would be a sight to see!!
the primary function block-->DC and pas-->AC is 100% from the start and if you are going to use them why would a manufacturer spend money on buring them in..
i know tubes need some time, but caps sound different when they charged/discharged  for couple of hours or even a day after turning my console back on! but porbably got nothing to do with burning in
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mell

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Re: burning in capacitors
« Reply #8 on: January 15, 2011, 04:06:30 pm »

double post,  Embarassed
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MagnetoSound

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Re: burning in capacitors
« Reply #9 on: January 16, 2011, 01:28:30 pm »


If your capacitors are burning, you should put them out.

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Music can make me get right up out of my chair and start dancing or it can get me so pumped up I have to walk around the block.
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Jim Williams

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Re: burning in capacitors
« Reply #10 on: January 18, 2011, 09:55:38 am »

mell wrote on Sat, 15 January 2011 13:01

Geoff Emerick de Fake wrote on Wed, 12 January 2011 19:18

According to JW in this thread, there are some caps manufacturers who recommend burning-in.
The idea of having to burn-in brand new components makes me rage. If they need burn-in, why didn't the manufacturer do it?
By not doing it, the manufacturer takes the risk that his products are used incorrectly and as a result, be misrepresented.


burning in 2.000 caps a day? that would be a sight to see!!
the primary function block-->DC and pas-->AC is 100% from the start and if you are going to use them why would a manufacturer spend money on buring them in..
i know tubes need some time, but caps sound different when they charged/discharged  for couple of hours or even a day after turning my console back on! but porbably got nothing to do with burning in



I have done break in's for customers. (No, I didn't STEAL anything!). Occasionally I get a request for the high end film caps and the user doesn't have the time for break in or needs it right when they first use it, those were usually consoles that needed to be put back into service quickly.

I set up a square wave oscillator with a goodly amount of output current. Then I drive the cap with about 10k hz for 2 days. That cap is loaded by a 100 ohm resistor so it absorbs plenty of current. 10k hz square waves will exercise the layers real good. It's sort of like slapping the cap rather than bending it.

With the high end film and foil caps I usually hear a difference in about 8 hours. It's a more "relaxed" sound, the harder edges soften up, the stridency of the film caps is reduced.
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Jim Williams
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MagnetoSound

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Re: burning in capacitors
« Reply #11 on: January 18, 2011, 10:55:26 am »

Jim Williams wrote on Tue, 18 January 2011 14:55

I set up a square wave oscillator with a goodly amount of output current. Then I drive the cap with about 10k hz for 2 days. That cap is loaded by a 100 ohm resistor so it absorbs plenty of current.




Jim,

To get an idea of how much current, roughly what percentage of rated voltage would you drive into that 100 ohms?

Also, are we talking about relatively low value film caps here? A few microfarads or less?


Thanks,
Dan
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Music can make me get right up out of my chair and start dancing or it can get me so pumped up I have to walk around the block.
It can also knock me back and make me sit there and cry like a little baby. This shit is as powerful as any drug!!!
- Larry DeVivo

GREGL

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Re: burning in capacitors
« Reply #12 on: January 18, 2011, 03:56:23 pm »

While the effect doesn't seem to be as noticeable with most film caps, electrolytics certainly benefit from some  run time. Some years ago I recapped two Quad 33 stereo preamps. I listened to both right after the recaps and could hear no difference between them. Out of curiosity I let one sit unused and ran pink noise through the other for two weeks. I turned the burn in unit off for a day. I then turned both on and let them sit for a day just to make sure they were "warmed up". The unit which had been running with the pink noise sounded noticeably better (in my opinion anyway). Less harsh, more dynamic. After a couple of weeks doing music duty in my shop the "unburned" unit came into its own and sounded pretty close to the other.

I have noticed over and over that when replacing caps there does seem to be some improvement in sound over time.

But one does have to be careful in evaluating these types of things. The change can happen if a unit hasn't been used for a while and no parts have been replaced. Also, changes in line voltage and spectral purity of the line voltage can create a similar change (at my house there are big changes between daytime and late at night). What your ears have been subjected to  before your evaluation can make a difference. And as mentioned above, your ears can adjust, giviing the impression things are better (you might be better off not listening to the unit while it is burning in to prevent this from happening, however your brain does not have very good "sonic memory" so you may not remember what you heard before properly). So as Fletcher says "YMMV".

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Jim Williams

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Re: burning in capacitors
« Reply #13 on: January 19, 2011, 12:03:40 pm »

MagnetoSound wrote on Tue, 18 January 2011 07:55

Jim Williams wrote on Tue, 18 January 2011 14:55

I set up a square wave oscillator with a goodly amount of output current. Then I drive the cap with about 10k hz for 2 days. That cap is loaded by a 100 ohm resistor so it absorbs plenty of current.



Jim,
To get an idea of how much current, roughly what percentage of rated voltage would you drive into that 100 ohms?
Also, are we talking about relatively low value film caps here? A few microfarads or less?
Thanks,
Dan



These are under 5 uf caps, usually. About 10 volts into 100 ohms works well. Slap them with a 10k hz square wave, not sine or pink noise.
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Jim Williams
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MagnetoSound

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Re: burning in capacitors
« Reply #14 on: January 19, 2011, 12:29:30 pm »

Thanks Jim, I will give it a try.

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Music can make me get right up out of my chair and start dancing or it can get me so pumped up I have to walk around the block.
It can also knock me back and make me sit there and cry like a little baby. This shit is as powerful as any drug!!!
- Larry DeVivo

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