Author Topic: no more center negative DC-plugs!  (Read 16376 times)

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Offline VK3DRB

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Re: no more center negative DC-plugs!
« Reply #25 on: October 14, 2015, 01:52:45 am »
A classic example where standards should have been introduced for DC connector polarity, such as IEC, AS or UL. The world stuffed up big time on DC connectors... it has been a free-for-all and it should not have been. I have a relative who blew up an expensive hand held game after he plugged a reverse polarity DC plug into the machine. It had no reverse polarity protection diode.

Another stuff-up... English, EU and Australian mains plugs. We all use 220V-240, so whey the heck do we have different plugs?

And another bigger stuff-up... Japan 100V, US 110V and Australia 240V. Lower voltage is safer form an electrocution perspective, but more dangerous with house fires (ie: higher current).

And the biggest stuff-up of all... Driving on the left in the UK, HK, NZ and Australia; and other countries drive on the right.

Standards might inhibit creativity, but they do make a lot of sense.
 

Offline vk6zgo

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Re: no more center negative DC-plugs!
« Reply #26 on: October 14, 2015, 01:55:28 am »
Oh of course. ...yes. SMPS has made things far smaller, lighter, and more efficient. All that at the expense of complexity. Shade tree mechanics step aside......

Sent from my SAMSUNG-SM-G890A using Tapatalk

I think that karoru was pointing out that the Nintendo box just had a bridge rectifier,followed by a linear regulator.
Because of this, the actual box could run from low voltage ac or dc.

SMPS supplies have been around for a long time--I fixed a lot of them back in the 1980s & '90s.
A good Oscilloscope,a DMM,& most importantly,a schematic helps a "shade tree mechanic" quite a bit! ;D

The reason modern units are difficult to fix is lack of the schematic.
 

Offline vk6zgo

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Re: no more center negative DC-plugs!
« Reply #27 on: October 14, 2015, 02:46:01 am »
A classic example where standards should have been introduced for DC connector polarity, such as IEC, AS or UL. The world stuffed up big time on DC connectors... it has been a free-for-all and it should not have been. I have a relative who blew up an expensive hand held game after he plugged a reverse polarity DC plug into the machine. It had no reverse polarity protection diode.

Another stuff-up... English, EU and Australian mains plugs. We all use 220V-240, so whey the heck do we have different plugs?

And another bigger stuff-up... Japan 100V, US 110V and Australia 240V. Lower voltage is safer form an electrocution perspective, but more dangerous with house fires (ie: higher current).

And the biggest stuff-up of all... Driving on the left in the UK, HK, NZ and Australia; and other countries drive on the right.

Standards might inhibit creativity, but they do make a lot of sense.


Oz & UK think their styles of plug are better designed than  others---with some justification.
230/240v allows the use of higher power appliances with thinner conductors.
100v/110v exists for complex historical reasons.

Driving on the left?---try India,Pakistan,Bangladesh,Malaysia,Thailand,Indonesia,Singapore,South Africa,Kenya,Japan,& many others.
 

Online BradC

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Re: no more center negative DC-plugs!
« Reply #28 on: October 14, 2015, 04:32:01 am »
230/240v allows the use of higher power appliances with thinner conductors.

Lower transmission losses allowing fewer but bigger pole top transformers.. there are a few advantages to higher mains voltages.

The strangest thing I've ever had to get used to was the frequency. I played a couple of gigs in the US years ago and I could not adjust to the 60Hz hum from the guitar amp. It just sounded wrong!
 

Offline jwm_

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Re: no more center negative DC-plugs!
« Reply #29 on: October 14, 2015, 04:50:37 am »
A classic example where standards should have been introduced for DC connector polarity, such as IEC, AS or UL. The world stuffed up big time on DC connectors... it has been a free-for-all and it should not have been. I have a relative who blew up an expensive hand held game after he plugged a reverse polarity DC plug into the machine. It had no reverse polarity protection diode.

Another stuff-up... English, EU and Australian mains plugs. We all use 220V-240, so whey the heck do we have different plugs?

And another bigger stuff-up... Japan 100V, US 110V and Australia 240V. Lower voltage is safer form an electrocution perspective, but more dangerous with house fires (ie: higher current).

And the biggest stuff-up of all... Driving on the left in the UK, HK, NZ and Australia; and other countries drive on the right.

Standards might inhibit creativity, but they do make a lot of sense.

There is a barrel jack standard, somewhat belatedly, all the plugs you see with the yellow tips (supossedly) follow the EIAJ standard.
https://en.wikipedia.org/wiki/EIAJ_connector

There was also an attempt at a standardized international 220V plug. It has not exactly taken off.
https://en.wikipedia.org/wiki/IEC_60906-1

Offline iampoor

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Re: no more center negative DC-plugs!
« Reply #30 on: October 14, 2015, 06:35:17 am »
In Audio gear (guitar pedals etc...) Center Negative is a (pretty well) accepted standard.
 

Offline JoeB83

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Re: no more center negative DC-plugs!
« Reply #31 on: October 14, 2015, 06:48:32 am »
In Audio gear (guitar pedals etc...) Center Negative is a (pretty well) accepted standard.

+1

I'm a bass player. All of my effects pedals have center negative barrels.

P.S. I know a lot of guitar players will say 'bass players don't need effects', but I like having an overdrive and an octave pedal, and a few others available.
 

Online bingo600

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Re: no more center negative DC-plugs!
« Reply #32 on: October 14, 2015, 04:53:01 pm »
A new 15v/3A switcher i bought , and me not testing , costed me a FEI-5680A Rubidium.
People making Center negative psu's should be put away for a loooonnng time  :-- :--

Or maybe i shouldn't assume , but it was my first encounter with such a devlish device.

/Bingo
 

Offline Galenbo

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Re: no more center negative DC-plugs!
« Reply #33 on: October 14, 2015, 05:06:18 pm »
Center negative DC plugs are used because that way the switched element is +ve not gnd. Don't want to be switching ground references when you are using audio or music gear, so they make the center pin negative.

I always thought it made perfect sense.
What's the relation between where a wire is sitting, and a wire that is switched?
If you try and take a cat apart to see how it works, the first thing you have on your hands is a nonworking cat.
 

Offline John Coloccia

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Re: no more center negative DC-plugs!
« Reply #34 on: October 14, 2015, 05:21:00 pm »
Center negative DC plugs are used because that way the switched element is +ve not gnd. Don't want to be switching ground references when you are using audio or music gear, so they make the center pin negative.

I always thought it made perfect sense.
What's the relation between where a wire is sitting, and a wire that is switched?

All of the commonly available DC jacks switch the barrel, not the center pin, and we use that switch to disconnect battery +. Also, in effects pedals anyway, the way the battery is switched on is a stereo jack is used, and battery ground goes to the inner tip of the stereo jack. When you plug in a mono 1/4" plug, it connects the inner tip to the sleeve and makes the ground. So all of this adds up to generally having center negative plugs. That's how Boss started doing it decades ago, and now it's pretty much THE standard everyone uses unless you absolutely have to do something else.

Like I said before, though, in practice, it's a non issue. The transformer isolates the plug, so it's actually quite difficult to cause a problem unless you're really trying. Even power supplies with multiple outputs are generally isolated these days, all but the cheapest solutions, but even if you short to the case with non-isolated multiple outputs, even the cheap power supplies generally have some sort of crowbar protection and just shut off.

Anyhow, that's the history of why it's the way it is. 30 years ago, someone came up with a solution that worked very well with commonly available parts, and everyone quickly standardized on that solution. There was actually a little fight for a while. I still have a couple of old effects here that are expecting something like 1/8" phono plug for power. Now THAT was easy to short out if it was just laying around, and it disappeared right quick.
« Last Edit: October 14, 2015, 05:26:43 pm by John Coloccia »
 

Offline jwm_

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Re: no more center negative DC-plugs!
« Reply #35 on: October 15, 2015, 01:48:36 am »

Anyhow, that's the history of why it's the way it is. 30 years ago, someone came up with a solution that worked very well with commonly available parts, and everyone quickly standardized on that solution. There was actually a little fight for a while. I still have a couple of old effects here that are expecting something like 1/8" phono plug for power. Now THAT was easy to short out if it was just laying around, and it disappeared right quick.

I have seen a fair number of effects that take 9V AC and some DC ones with bridge rectifiers, presumably for backwards compatibility with the AC ones. I wonder if it is common to just have a bridge rectifier in them in general. Who has a collection of 9V effects they want to take a poll of.

Offline John Coloccia

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Re: no more center negative DC-plugs!
« Reply #36 on: October 15, 2015, 02:57:20 am »

Anyhow, that's the history of why it's the way it is. 30 years ago, someone came up with a solution that worked very well with commonly available parts, and everyone quickly standardized on that solution. There was actually a little fight for a while. I still have a couple of old effects here that are expecting something like 1/8" phono plug for power. Now THAT was easy to short out if it was just laying around, and it disappeared right quick.

I have seen a fair number of effects that take 9V AC and some DC ones with bridge rectifiers, presumably for backwards compatibility with the AC ones. I wonder if it is common to just have a bridge rectifier in them in general. Who has a collection of 9V effects they want to take a poll of.

There's no need to take a poll. I can tell you that there are many, many, many thousands of different effects pedals out there, and the VAST majority take a standard Boss 9V adapter. Some Line6 effects take 9V AC. There were a handful that used a rectifier and take anything pretty much anything. 9VDC, however, is nearly universal otherwise.
 

Offline JoeB83

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Re: no more center negative DC-plugs!
« Reply #37 on: October 15, 2015, 05:09:20 am »

Anyhow, that's the history of why it's the way it is. 30 years ago, someone came up with a solution that worked very well with commonly available parts, and everyone quickly standardized on that solution. There was actually a little fight for a while. I still have a couple of old effects here that are expecting something like 1/8" phono plug for power. Now THAT was easy to short out if it was just laying around, and it disappeared right quick.
I have seen a fair number of effects that take 9V AC and some DC ones with bridge rectifiers, presumably for backwards compatibility with the AC ones. I wonder if it is common to just have a bridge rectifier in them in general. Who has a collection of 9V effects they want to take a poll of.

There's no need to take a poll. I can tell you that there are many, many, many thousands of different effects pedals out there, and the VAST majority take a standard Boss 9V adapter. Some Line6 effects take 9V AC. There were a handful that used a rectifier and take anything pretty much anything. 9VDC, however, is nearly universal otherwise.

I don't have a lot of effects, but:
All 12 of my Boss pedals are center-negative. (Duh)
Line 6 Bass Pod: 9VAC
A couple "boutique" pedals: all center-negative.
 

Offline Galenbo

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Re: no more center negative DC-plugs!
« Reply #38 on: October 15, 2015, 08:00:53 am »
What's the relation between where a wire is sitting, and a wire that is switched?

All of the commonly available DC jacks switch the barrel, not the center pin, and we use that switch to disconnect battery +. Also, in effects pedals anyway, the way the battery is switched on is a stereo jack is used, and battery ground goes to the inner tip of the stereo jack. When you plug in a mono 1/4" plug, it connects the inner tip to the sleeve and makes the ground. So all of this adds up to generally having center negative plugs. That's how Boss started doing it decades ago, and now it's pretty much THE standard everyone uses unless you absolutely have to do something else....
Sorry, I still don't understand why jacks are related to switch.
Do you mean the center makes contact before the outside does, when plugging in?
If you try and take a cat apart to see how it works, the first thing you have on your hands is a nonworking cat.
 

Offline John Coloccia

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Re: no more center negative DC-plugs!
« Reply #39 on: October 15, 2015, 10:46:19 am »
What's the relation between where a wire is sitting, and a wire that is switched?

All of the commonly available DC jacks switch the barrel, not the center pin, and we use that switch to disconnect battery +. Also, in effects pedals anyway, the way the battery is switched on is a stereo jack is used, and battery ground goes to the inner tip of the stereo jack. When you plug in a mono 1/4" plug, it connects the inner tip to the sleeve and makes the ground. So all of this adds up to generally having center negative plugs. That's how Boss started doing it decades ago, and now it's pretty much THE standard everyone uses unless you absolutely have to do something else....
Sorry, I still don't understand why jacks are related to switch.
Do you mean the center makes contact before the outside does, when plugging in?

The DC jacks have 3 terminals....call them 1, 2 and 3. 1 goes to the pin. 2 goes to the barrel. 3 goes to 2. When you plug in a DC jack, the connection between 3 and 2 is open.

So it's setup that 1 is ground, 2 is power, and 3 goes to battery +. With no plug installed, the battery powers the device. When the plug is installed, the battery is disconnected. Someone over at Boss got it in their head that this was the right way to do it, and everyone copied them. I guess the idea was that they really wanted to switch the battery +. Of course, they could have just switched battery -. Who knows. Maybe the idea was to do it in a screwy way so that you'd HAVE to use their adapter, and they figured that everyone else would do it differently.  :-//

Switching battery + makes sense, I guess, because you'd really rather not switch ground if the device is on. You can get some massive pops if you do that. It's worth noting Boss has always used a buffered bypass, so even when the device is switched "off", it's still on and buffering your signal, so it makes sense that they wouldn't want the pedal to be poorly behaved when plugging in a DC jack.
« Last Edit: October 15, 2015, 11:21:42 am by John Coloccia »
 

Offline madires

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Re: no more center negative DC-plugs!
« Reply #40 on: October 15, 2015, 11:48:19 am »
A new 15v/3A switcher i bought , and me not testing , costed me a FEI-5680A Rubidium.
People making Center negative psu's should be put away for a loooonnng time  :-- :--

Or maybe i shouldn't assume , but it was my first encounter with such a devlish device.

The latter >:D We know of the issue and got at least one DMM nearby. You shall measure voltages!

Hint: Label wall warts (which device is powered by that PSU?).
Business idea: do a kickstarter for a PSU polarity checker
 

Offline JoeN

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Re: no more center negative DC-plugs!
« Reply #41 on: October 15, 2015, 07:24:26 pm »
I test every one with my multimeter.  It's a very quick check.
Have You Been Triggered Today?
 

Offline wagon

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Re: no more center negative DC-plugs!
« Reply #42 on: October 15, 2015, 08:57:52 pm »
Yesterday I had a mother and her sons come into my workshop with a blown up radio that had the centre-negative experience.  The radio was centre-positve, but not the plugpack the young bloke used.  Magic smoke was released.
Hiding from the missus, she doesn't understand.
 

Offline Galenbo

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Re: no more center negative DC-plugs!
« Reply #43 on: October 16, 2015, 03:51:30 am »
...The DC jacks have 3 terminals...   ...When you plug in a DC jack, the connection between 3 and 2 is open.
... the battery powers the device. When the plug is installed, the battery is disconnected...
Thanks for the info. I never saw a DC jack with a switch, only saw this on PC's earphone jacks.
I never had anything to do with battery powered devices, always assumed the dc goes to a charging circuitry.

If you try and take a cat apart to see how it works, the first thing you have on your hands is a nonworking cat.
 


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