Adding an arc suppression capacitor across a power switch to stop speaker popping

snap, crackle and pop
empireboy
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Adding an arc suppression capacitor across a power switch to stop speaker popping

Post by empireboy » 19 Feb 2019 07:05

I have a vintage changer that injects a "pop" noise when the mechanism turns off at the end of a record.

A cam moves a switch and that apparently creates an arc which sends DC (?) to the speakers.

This is a Zenith changer. Instead of two wires going to the switch, there are three. Perhaps the third is for shutting off the rest of the console. Ignore the notes on the photo -- focus on the switch itself.

What kind / value of capacitor is recommended to stop the arcing noise? And how should the capacitor it be wired (i.e. if the cap is polarized, which side solders to where on the switch?)
wiring.jpg
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Spinner45
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Re: Adding an arc suppression capacitor across a power switch to stop speaker popping

Post by Spinner45 » 19 Feb 2019 08:53

Just solder a .047uf, 630 volt mylar cap across the switch and no more pops.
And call it a day.

Beobloke
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Re: Adding an arc suppression capacitor across a power switch to stop speaker popping

Post by Beobloke » 19 Feb 2019 14:00

The above will work fine but make sure the capacitor is a Class X2 type.

empireboy
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Re: Adding an arc suppression capacitor across a power switch to stop speaker popping

Post by empireboy » 19 Feb 2019 14:30

Are these caps polarized (one side positive and another negative)? If so, which side of switch does positive go to? Or does it not matter?

lenjack
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Re: Adding an arc suppression capacitor across a power switch to stop speaker popping

Post by lenjack » 19 Feb 2019 14:35

Don't think it matters, but others will chime in.

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Re: Adding an arc suppression capacitor across a power switch to stop speaker popping

Post by Athermos » 19 Feb 2019 16:12

empireboy wrote:
19 Feb 2019 14:30
Are these caps polarized (one side positive and another negative)? If so, which side of switch does positive go to? Or does it not matter?
Mylar or polystyrene capacitors are non polarized.

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Re: Adding an arc suppression capacitor across a power switch to stop speaker popping

Post by empireboy » 19 Feb 2019 16:15

If the mylar cap ever goes bad, does the power stay on all the time? Just curious what will happen.

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Re: Adding an arc suppression capacitor across a power switch to stop speaker popping

Post by empireboy » 19 Feb 2019 17:05

A few questions:

1. Is this part a good choice? Mouser part: 598-WMF6S47K-F

Film Capacitor .047UF 600V 10%

https://www.mouser.com/ProductDetail/Co ... WAxA%3D%3D

2. Is this part Class X2? Didn't see a mention on the datasheet.

3. Is mylar better than film in this application?

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Re: Adding an arc suppression capacitor across a power switch to stop speaker popping

Post by analogaudio » 20 Feb 2019 00:15

Then it is not X2

Mylar is one brand name for a type of polyester which is plastic film, special plastic film.

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Re: Adding an arc suppression capacitor across a power switch to stop speaker popping

Post by Spinner45 » 20 Feb 2019 02:06

analogaudio wrote:
20 Feb 2019 00:15
Then it is not X2

Mylar is one brand name for a type of polyester which is plastic film, special plastic film.
All this babble about X2 caps!
I gave the OP a simple effective and reliable cure for the problem, using a high-rated (630V) mylar cap, which has been used plenty of times across AC power switches in the past - BY the original manufacturers I might add.
It's used in amps, receivers, etc., and NOT an X2 either, because it's NOT required.
Yet I always get this followup responses with others insisting (obsessed) on using an X2, which now shows that the OP is confused over "x2" etc etc etc.

Just put a damn, and I will say it yet AGAIN..... .047uf/630volt MYLAR across the damn switch and be DONE with the issue.
I've replaced hundreds over the years in the shop without a damn issue.... ever.
Why do others on here make things so damn hard to understand?

HERE is a photo of one, to be clear.
LD047.jpg
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lenjack
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Re: Adding an arc suppression capacitor across a power switch to stop speaker popping

Post by lenjack » 20 Feb 2019 04:54

Agreed. Now, the question is, where do you by one these $0.90 pieces, for less than $9.00, plus $8 shipping, when you don't live near an electronics distributor, and Radio Shack is gone. :? :?: #-o

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Re: Adding an arc suppression capacitor across a power switch to stop speaker popping

Post by Spinner45 » 20 Feb 2019 06:30

lenjack wrote:
20 Feb 2019 04:54
Agreed. Now, the question is, where do you by one these $0.90 pieces, for less than $9.00, plus $8 shipping, when you don't live near an electronics distributor, and Radio Shack is gone. :? :?: #-o
Radio shack since the 80's, never carried 630 volt capacitors anyway, their stock was limited to "transistor" age items, 50-100 volt caps.
As far as only buying one, that's the pity of it all.
I usually buy quantities of such things, but then again that's me, since I'm always doing repairs, etc.

X2 capacitors are not required across a power switch, they're designed for directly across the AC line input.

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Re: Adding an arc suppression capacitor across a power switch to stop speaker popping

Post by abril » 20 Feb 2019 09:44

X2 capacitors are not required across a power switch, they're designed for directly across the AC line input.
=D>
Why do others on here make things so damn hard to understand?
:roll:

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Re: Adding an arc suppression capacitor across a power switch to stop speaker popping

Post by DeepEnd » 20 Feb 2019 13:17

Whilst X2 rated capacitors are not mandatory across a switch just consider that with the switch “open” in the off position the capacitor is effectively fully across the mains voltage and in a deck it will be like this for most of its life when not in use unless you unplug from the mains. Personally I would rather have a capacitor designed to fail open circuit in this situation rather than potential go short and start up the motor/get hot!!

I suspect that is why most suggest X2 or Y rated caps as a belt and braces approach given the small difference in cost.

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Re: Adding an arc suppression capacitor across a power switch to stop speaker popping

Post by Beobloke » 20 Feb 2019 13:58

Spinner45 wrote:
20 Feb 2019 02:06
analogaudio wrote:
20 Feb 2019 00:15
Then it is not X2

Mylar is one brand name for a type of polyester which is plastic film, special plastic film.
All this babble about X2 caps!
I gave the OP a simple effective and reliable cure for the problem, using a high-rated (630V) mylar cap, which has been used plenty of times across AC power switches in the past - BY the original manufacturers I might add.
It's used in amps, receivers, etc., and NOT an X2 either, because it's NOT required.
Yet I always get this followup responses with others insisting (obsessed) on using an X2, which now shows that the OP is confused over "x2" etc etc etc.

Just put a damn, and I will say it yet AGAIN..... .047uf/630volt MYLAR across the damn switch and be DONE with the issue.
I've replaced hundreds over the years in the shop without a damn issue.... ever.
Why do others on here make things so damn hard to understand?

HERE is a photo of one, to be clear.

LD047.jpg
Actually, despite the stroppy way in which the above poster has put it, he's made me think and and I apologise for my duff information - DO NOT USE an X2 here! If a mod could edit my earlier post, I'd be grateful.

A standard capacitor should be OK, or use a Class Y2 for the correct level of safety here.

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