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Author Topic: Here's a good one! (Headphones)  (Read 16138 times)

Offline Simulated

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Here's a good one! (Headphones)
« on: 12/01/2008 03:01:03 »
Whatever kind you cna find!

2.5 mm
3.5 mm
etc


 

Offline Karen W.

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« Reply #1 on: 12/01/2008 03:28:05 »
Measurements? How do I tell what mine are?
mine are ALTEC LANSING SAYS NOTHING ELSE AND I THREW AWAY THE BOX QUITE ALONG TIME AGO!
« Last Edit: 12/01/2008 03:36:07 by Karen W. »
 

Offline Simulated

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« Reply #2 on: 12/01/2008 12:50:50 »
Um what do you plugg them into? a cd player or a phone?

and whom invented any kinds of cell phones
 

Offline Karen W.

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« Reply #3 on: 12/01/2008 14:44:22 »
My computer! I bought good speaker system a long time ago so my computer has great sound. Also it can be used on my skype program but I don't. I just listen to things quietly  sometimes..

I don't know who invented cell phones!
 

Offline Simulated

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« Reply #4 on: 12/01/2008 14:51:00 »
Who invented headphones karen lol..

then they are 3.5 mm
 

Offline Karen W.

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« Reply #5 on: 12/01/2008 15:03:02 »
Um what do you plug them into? a CD player or a phone?

and whom invented any kinds of cell phones

Lol.. You asked who invented cell phones??? LOL

Who invented headphones karen lol..

then they are 3.5 mm

 I do not know who invented headphones either!!!

How does one tell other then reading a box what the 3.5 mm stands for , size or some kind of sound rating.. do tell as I am not knowledgeable in these things?
« Last Edit: 12/01/2008 15:05:13 by Karen W. »
 

Offline Simulated

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« Reply #6 on: 12/01/2008 15:16:17 »
Well the both have phones in them and ya lol i was tired last night
 

Offline Karen W.

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« Reply #7 on: 12/01/2008 15:26:01 »
What does the 3.5 stand for Ryan?
 

Offline Simulated

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« Reply #8 on: 12/01/2008 15:28:55 »
3.5 mm..i bevile that would be around the part you plugg in
 

Offline Karen W.

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« Reply #9 on: 12/01/2008 16:30:10 »
Humm I will check, but what does it mean.. a size rating or sound or what..?
 

Offline that mad man

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« Reply #10 on: 12/01/2008 17:38:12 »
Its to do with the plug size Karen, nothing else.

The older type of headphones (cans) had jacks that were 1/4" in diameter. They have mainly be replaced by the 3.5mm jack and its a fairly standard size headphone plug for most players now. Smaller equipment because of space restrictions can have a 2.5mm jack socket.

 

another_someone

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« Reply #11 on: 12/01/2008 23:40:32 »
I still have headphone on my HiFi (1980's vintage) that has 1/4" jacks, and phono connector to connect the units together.

Headphones have been around since the days of crystal radios, where there was just not the power output to drive free standing speakers.
 

Offline Karen W.

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« Reply #12 on: 13/01/2008 00:30:05 »
Somewhere I have a huge jack that plugs into a big old stereo we used to have set up in the house. I suspect that it was the same about three inches long and really fat! fit into a large hole!
 

Offline turnipsock

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« Reply #13 on: 13/01/2008 00:42:37 »
...well, I have wireless headphones.

They are one of my top ten fav possesions. It means that you can go to the toilet and still listen to Bucks Fizz. There are few drawbacks, but one amusing story was when my mum went outside and the door blew shut. She knocked on the window and as the dog is deaf, she was out there for ages.

The other problem was when my mum didn't lock the toilet door. I think she said something like "didn't you hear me shouting?"
 

Offline Karen W.

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« Reply #14 on: 13/01/2008 01:58:08 »
LOL LOL! Where did you get wireless headphones and how do they work? Are they expensive?
 

Offline Simulated

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« Reply #15 on: 13/01/2008 14:56:01 »
Wow they actually have wireless headphones? Darn I was going to make them :( lol.

Thanks for the info George! I'm a little young. What's a crystal radio?

 

Offline Karen W.

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« Reply #16 on: 13/01/2008 18:20:04 »
Wow they actually have wireless headphones? Darn I was going to make them :( lol.

Thanks for the info George! I'm a little young. What's a crystal radio?



Hey since I posted I have read another thread where Neil posted speaking of wireless headphones. I honestly did not know they made them. LOL

Here is wiki's on Crystal Radios Ryan!

http://en.wikipedia.org/wiki/Crystal_radio


Crystal radio
From Wikipedia, the free encyclopedia


The crystal radio receiver (also known as a crystal set) is a very simple kind of radio receiver. It needs no battery or power source except the power received from radio waves by a long outdoor wire antenna.

Simple crystal radios are often made with a few hand made parts, like an antenna wire, tuning coil of copper wire, crystal detector and earphones. Because crystal radios are passive radio receivers, they are technically distinct from ordinary radios containing active powered amplifiers in many respects. This is because they must receive and preserve as much electrical power as possible from the antenna and convert it to sound power whereas ordinary radios amplify the weak electrical energy "signal" from the radio wave. Today making and operating crystal radios is a popular hobby for many reasons, including:

    * Historical and nostalgic significance
    * The astonishing results one can get from its utter simplicity
    * The challenge of receiving weak distant signals without amplification

Crystal radios can be designed to receive almost any radio frequency since there is no fundamental limit on the frequencies they will receive. The most common crystal radios are designed for the AM Broadcast Band and the 49-meter international short wave band, partly because the radio waves are stronger in those bands. Early radios commonly received spark signals as low as 20 kHz and below. Although crystal radios are designed to detect AM, they also frequently detect FM fairly well which is in the 100 MHz range.

Groups of enthusiasts[1] and a number of web sites[2] are devoted to their construction. Regular contests are held comparing the performance of various designs with each other. Reportedly, [3] modern diodes, ultra-thin litz wire inductors, and low loss capacitors yield performance far beyond that of the original receivers.

[edit] How it works (simple version)
Pictorial diagram showing parts and connections for a crystal radio.
Pictorial diagram showing parts and connections for a crystal radio.

A crystal radio receives programs broadcast from radio stations. Radio stations convert sound into radio waves and send out the waves everywhere. Radio waves travel across the crystal radio antenna all the time. Radio waves make radio wave electricity flow between the antenna wire and the ground wire. This electricity is connected to the crystal radio by the antenna and ground wire. The crystal radio uses a tuner to tune the electricity to receive just one station. The tuner can be as simple as an adjustable one-slider tuning coil that resonates with the antenna because the antenna also acts like a capacitor. Then it uses a crystal detector to convert this radio wave electricity back to sound electricity. The detector can be made from a special rock of galena in a holder. It uses earphones to convert the sound electricity to sound you can hear in the earphones.
 

Offline Simulated

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« Reply #17 on: 13/01/2008 18:48:26 »
Ah thanks Karen!!
 

Offline Karen W.

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« Reply #18 on: 13/01/2008 19:30:10 »
Your welcome.. I bet George could tell you about his better.
 

Offline Simulated

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« Reply #19 on: 14/01/2008 01:09:39 »
Yes, but Wiki don't lie. That much..
 

Offline Karen W.

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« Reply #20 on: 14/01/2008 01:20:37 »
Sometimes wiki is not correct!
 

another_someone

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« Reply #21 on: 14/01/2008 02:11:53 »
OK, firstly, I don't recollect ever having tried to build a crystal set.

You quoted that crystal sets typically pick up AM - I am not all sure how they could ever pick up anything but AM.

The crystal referred to is a crystal of germanium.  What the people who originally were building crystal sets (in the 1930s) were doing was using technology that would not be properly understood for another 30 years, and would lead to the development of the transistor in the 1960s.

In an ordinary crystal of germanium, you would have natural impurities.  These impurities would create natural P and N region doped germanium, and if you could fiddle a couple of pieces of wire (commonly referred to as cats whiskers) to find a section of the crystal where a section of naturally doped P region was next to a naturally doped N region, you would have a natural soil state diode.  You could then use the diode as a rectifier.

The idea of an AM signal is that you have a carrier signal that is oscillating at several megahertz (e.g. the 49 metre band mentioned above would have a carrier oscillating at around 6.1MHz).  The audio signal then modulates this carrier, so that the amplitude of the carrier signal varies with the amplitude of the audio signal (hence why it is known as Amplitude Modulation, or AM).

You then use a long piece of wire as an aerial to pick up the signal, and feed it through a coil and capacitor.  The coil and capacitor (which are tuned to the frequency you desire) are designed to resonate at the frequency of the carrier signal you want to pick up, and block out as far as possible all the frequencies you do not want.

You now have the desired radio signal, but that radio signal is oscillating between a positive and negative voltage, and although the amplitude of that voltage is proportionate to the audio signal you want, but the average voltage between the positive and negative voltage is zero.  This is where the germanium crystal comes in.  The germanium crystal acts as a rectifier, so you can use it either to block out the negative part of the oscillation, or the positive part of the oscillation.  Whichever half you block out, the remaining half now no longer has an average value of zero, but it has an average value that varies with the audio signal you are trying to detect.  Although this audio signal is extremely weak, since it was only the signal received by the aerial you have erected, but if you feed the signal into sensitive pair of headphones, you can nonetheless hear the sound that was carried on the radio signal.

Crystal sets became obsolete when valves (vacuum tubes) started to become available, since valves were more predictable that natural germanium crystals, and you could also build valve amplifiers that could drive large loudspeakers.  Also, once you had active components, such as diodes, you could develop far more sophisticated tuning circuits (such as superheterodyne tuning), or even other modulation techniques (such as FM, or SSB AM).

It was not until the 1960s that people started to find ways of carefully constructing germanium (and later silicon) crystals where they could control where the doping actually happened (rather than trying to fiddle around with a naturally impure crystal to see where nature had doped it), and so was born the solid state diode and transistor, and from that the modern large scale integrated circuit etched on a wafer of silicon crystal.

In fact, when Wiki talks about people still building crystal sets, I don't think they really are talking about crystal sets in the original sense, because these days they would still use premanufactured silicon diodes rather than trying to fiddle around with a real natural crystal of germanium; but they might still play with a simple coil and variable capacitor for the tuning circuit, and no amplification, but simply substitute the modern diode for the more fiddly germanium crystal.
« Last Edit: 14/01/2008 02:24:24 by another_someone »
 

Offline Karen W.

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« Reply #22 on: 14/01/2008 02:45:59 »
LOL George is right I misread his post above..and inverted two lines and got it screwed up!

Sorry George. For some reason thought he said something about his vintage crystal

radio..LOL DUH.. I thought you had one your headphones worked with, not that you built! LOL

I agree with you... but I know nothing but the little I read there on wiki pedia..

Glad you are so much more informed then Me.. Thanks George!

As far as wiki I did not print the whole thing as it was huge but just wanted Ryan to get the jest of it..
 

Offline neilep

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« Reply #23 on: 14/01/2008 03:03:26 »
1/4 inch jack and phono plugs (now called interconnects) rules !!

I hate those 1/8 of an inch things but there's no escaping them....Mind you...I've never seen a big TV or a hifi amp or heaphone amp or big headphones use anything less than 1/4 inch !!.....though some headphones have the 2 in 1 plugs too....ie: an 1/8 inch inside a 1/4 inch jack....
 

Offline Karen W.

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« Reply #24 on: 14/01/2008 03:06:22 »
Does the size of the Jack make a difference in sound quality or something..???
 

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« Reply #24 on: 14/01/2008 03:06:22 »

 

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