Lets talk POWER CORDS

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Lasonic TRC-920

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OK, I was searching Boomboxery for information regarding power cords and found this thread HERE It gives a great description of all the different styles of plugs, which is great. But it doesn't mention anything about application.

My question is:
Are there any VOLTAGE differences or IMPEDANCE differences that are determined by the shape of the plug?

Say you have a SQUARE plug, does that represent HIGHER VOLTAGE than say a ROUND plug?

How about Round on one side and Square on the other. Obviously, the manufacturer is telling us SOMETHING about the power / cord compatibility. But what is it?

Is there a chart that should be created? Does one exist?

Can I use a power cord that has rounded sides in a radio with a square hole? If so, is the power cord for a lower voltage radio, possibly not delivering the right amount of power and subsequently HURTING my radio?

SEE, This is what I use Lasonic's...the damn cord is connected! :blush: :lol:

Your thoughts....
 

Northerner

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Every box I have has the same figure of eight cord other than one Sony that has a rectangular one...so the question has never occurred to me...interesting tho...my guess would be that it wouldn't make any difference but what do I know lol :-)
 

Beosystem10

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It only matters if you're an audiophool who believes that oxygen-free copper internal wires, all spun anti clockwise by Balinese maidens who work naked and don't eat anything with a face, will make the slightest bit of difference!

Most of my stuff is floating chassis-based standard fayre with fig eight or, in the cases of some early Sanyo and Sony kit, rectangular connections that don't match the fig eight pattern. My horrible Hitachi 3D boombox has its mains lead permanently attached but I suspect that this is because the mains plug is the heaviest component in there and if the lead weren't permanently stowed in a compartment at the back next to the battery, the thing would blow away in the slightest breeze.
Then there are the Russian sets which have a tiny, 3 pin connection like a miniature version of the clover found in laptop PSUs, their chassis is at mains potential and their PSU is an autotransformer rather than the isolated one that most other makers use. I find that they sound best on battery, that way the 50Hz hum that competes with the music isn't there!
 

redbenjoe

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agree with john -
or in simple car talk --

the entire difference may be like drilling two 1/4" holes in your gas pedal -
to reduce the weight of a 400HP ferrari :-D
 

Alberto

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I believe the one difference between the rectangle and the figure eight is what company they were using to supply the AC power cord or vise versa. I believe that the only advantage of the figure eight over the rectangle is that it is a tighter fit ( the center two slots ) so it will not slip off easily. It has nothing to do with polarity because the two center slots ( one on each side ) on the figure eight are the same. All the power cord does is supply 120 volts AC to a transformer and the circuitry after the transformer then changes it to DC voltage ( there is no direct connection between the AC input "Primary Side" and the output "Secondary Side" in the transformer) and because the input power is alternating current to the transformer AC polarity is not a big issue.
 

Beosystem10

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It isn't if it's in a double insulated set and is floating, but if it's an autotransformer, one pole of each winding is earthed to the chassis.
And a transformer doesn't convert AC to DC, that's the job of the rectifier and the reason why DC mains equipment uses large ceramic droppers (or line cord droppers in most sets designed to run at 117V rather than the 250V we use here) as DC is no use to a transformer.
This is why the rectifier in Universal (AC or DC mains compatible) equipment is often a pentode rather than having only the three junctions required to provide a useable (if rather noisy) DC waveform from an AC input via a dropper, that way it may save space and can also act as an oscillator to create AC from the DC supply much like an AC inverter does in homes with only DC mains.

I believe the one difference between the rectangle and the figure eight is what company they were using to supply the AC power cord
That's very likely as, before these things became more or less standardised, there were a great many different types. The fig eight style that we know these days was probably, at some stage in the development of portable equipment, the cheapest option available regardless of whether it was the best in terms of its reliability though happily, it probably is unlike poor Betamax video which although technically vastly superior and capable of much better resolution, lost out to VHS because VHS was cheaper to make from the tapes right up to the parts in the machines.

Here's an example of another connector style that was used by many manufacturers of British portable radios in the 1950s and 1960s, it's a figure eight but larger than the one we all know and use. This design (seen here in my 1959 Bush MB60 radio) is the first I know of that includes a mechanical means of cutting the supply from the set's batteries (in this case a 90 Volt HT battery with a pair of parallel D cells for the LT heater supply, though earliest versions of the set used a combination HT/LT batter like that found in various Zenith Transoceanics), note that there's a small sliding toggle (made from a slab of Paxolin) above the slot where the lead goes. I run this one from replica HT batteries as it's an economical thing and this way I don't need to swap out all of the Hunts caps that would fail immediately if I were to run it from mains, but the correct leads for this socket were designed to fit flush with the cutout in the set's cover so that it could be used against a wall. When the leads do come up on eBay, they tend to cost more than the usual price of an otherwise perfect radio without its lead!


Click on the image above to show detail of that AC socket at the bottom corner of the set's chassis, predecessor of the figure eight we know or what? :-)
And this is the rebate in the back cover that allowed the original lead to fit flush:


And in case anyone wonders what the front looks like:


Some might recognise the shape as that same (David Ogle designed) cabinet was used for the later TR82, a transistorised version built on the same chassis, and the shape lives on in a truly shockingly bad modern replica with DAB built in, it uses the now universal smaller figure eight socket for its mains lead but that one doesn't sit flush to the back of the set. Here's the unique take on the figure eight seen attached to an MB60:
 

blu_fuz

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My 777Z is a rectangle plug and my 777H was a figure 8 plug. Figure that out! Boom!
 

im_alan_partridge

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blu_fuz said:
My 777Z is a rectangle plug and my 777H was a figure 8 plug. Figure that out! Boom!
Not only is my 575 the only one with a rectangle plug, but it also has a pathetically thin cable attached to it. Its almost like they forgot to put the outer insulation on it.
 

jimmyjimmy19702010

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Most of my 240v boxes use a rectangular plugs with only the occasional box using a figure 8. Some Hitachi & Panasonic boxes use figure 8, others use rectangular plugs. Seems pretty random to me although the newer the box, the more likely it uses figure 8 plugs.

James.... :-)
 

k2j

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blu_fuz said:
My 777Z is a rectangle plug and my 777H was a figure 8 plug. Figure that out! Boom!
I've bought a few boomboxes on the used market that have included wrongly the figure 8 plug which seems to be a touch wider than the usual boombox oval type plug. You can use them if you really jam them on, super cheesy. I've since shopped the goodwills buying up the proper oval plugs for those boomers (and the ones missing cords) for a measly $2 a pop.
 

blu_fuz

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k2j said:
I've bought a few boomboxes on the used market that have included wrongly the figure 8 plug .
I wasn't saying that the wrong cord is used on mine, but the actual shape of the power slot on the boombox for my 777H is rectangle while the 777H I had was a figure 8.

I too have seen the wrong shape wire pushed into a boombox.
 

AE_Stereo

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Beosystem10 said:
It only matters if you're an audiophool who believes that oxygen-free copper internal wires, all spun anti clockwise by Balinese maidens who work naked and don't eat anything with a face, will make the slightest bit of difference!
.....
Liked it.... The power all the way from power station to the wall outlet is running through all kind of nonsense cabling and crap wiring and still do people believe that the last piece of 1m cord that connects from the Chinese wall socket to the audio equipment will make a difference to the audible sound? Best definition for the crowd.




And :thankyou: for the rest of the technical stuff,
 

Beosystem10

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baddboybill said:
I do know that the wire is thicker and stiffer on the cords used for 220/240 :yes:


Bad Boy Bill
Sorry, but it isn't. Reason is that a device that consumes X amount of power uses half as much current if it runs on twice the PD so a UK box that uses 40 Watts at 253 Volts (UK average) needs a current at 0.158 Amps but the same 40 Watt load taken from a 117 Volt supply will take a current at 0.34 Amps, hence the cable in 250V devices can safely have half of the cross sectional area.

For a physical comparison, see the two clover leads in the attached image, the one with the thin, round insulation is a UK one and the one with the three much thicker, individually wrapped cores came with my "Test pilot" Google CR-48 Mario Fish netbook as sent out by Google to those who did the Chrome Beta testing in late 2010/early 2011.



The American spec lead is the one at the right, note also that it's so much stiffer than the UK-spec lead that it can stand clear of the floor just by being bent to that shape, whereas the thinner, softer one lies flat wherever it's put.
 
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