Use Earbuds/Earphones with Crystal Radio

How to use earbuds of earphones, including those from Apple, with a Crystal Radio. To do this, put a transformer between the crystal radio's output and the earbud. In this video I use a doorbell transformer but I found the small transformer attached to the circuit board in a microwave oven worked well too. The high voltage/higher turn count/higher resistance side goes to the crystal radio and the lower voltage/lower turn count/lower resistance side goes to the earphone. A small one-to-one/isolation transformer works well too as well as a small AC-to-AC wall adapter.
For my "Make Crystal Earphone/Earpiece for Crystal Radio - Homemade" video, watch:
• Make Crystal Earphone/...
For the "How a Crystal Radio Works" video, watch:
• How a Crystal Radio Works
For the "Piezoelectric generator LED lit by rain water" video, watch:
• Piezoelectric generato...
For my webpage about this same topic, using earbuds with a crystal radio, go to:
rimstar.org/equ...
For more about crystal radios, go to:
rimstar.org/equ...
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Music used throughout:
Decisions Kevin MacLeod (incompetech.com)
Licensed under Creative Commons: By Attribution 3.0
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[@Alex1M6]

Great video! You probably already know this but using transformers like this is called impedance matching. The transformer primary acts like a high impedance load to the crystal radio whilst the secondary acts like a low impedance source for the earbud.

[@acmefixer1]

The main difference between a power transformer and an audio transformer is the way the E and I laminations of the core are arranged. The power transformer has an E on the left and I on the right of the first layer, then an I on the left and an E on the right of the second layer and so on, so alternating layers have E or I on the left. This makes the core almost like a solid block and the transformer is optimized for 60 or 50 Hz. The audio transformer has all E's bundled together, and all I's bundled together, and they are assembled and held together with a piece of thick paper between the E's and I's. This air gap created by the paper optimizes the transformer for a wide band of audio frequencies. You should try to take one of the power transformers apart. The first E and I laminations is very hard to get out, but after that it's easier. A rubber mallet helps a lot but don't break the windings. Then you can put it back together with the paper and now you have a wider band transformer. But the way you have been doing it works, for noncritical use. The big MOT has too much core loss. Save it to make a spot welder. :-) Great video.

[@videolabguy]

Use the audio output transformer from an old transistor radio. It is usually the red one. OR the one to which the speaker is connected. You should have no trouble connecting the buds in parallel in this arrangement.

[@RimstarOrg]

I'm glad you like it. No difference really. I just wanted to use both terms so that people searching for either will find the video. I could have used earpods as well.

[@RimstarOrg]

(... continued) So we put a transformer between the resonant circuit (capacitor and coil) and the low impedance earbud. We put the high impedance side of the transformer on the resonant side. That's the side of the transformer with the most wire turns. Now the listening side doesn't siphon off too much energy from the resonant circuit so that the resonance (tuning) can still happen. See my "How a Crystal Radio Works" video for more on the resonant circuit. And hopefully I got that right! :)

[@RimstarOrg]

Sure. The magnetic permeability of the material does affect the inductance which in turn affects the range of resonant frequencies you'll be able to tune into. Air has a magnetic permeability of 1 (and the cardboard tube I use counts as just air). Iron is 100. Ferrite is from 16 to 640. The higher the permeability, the smaller diameter it can be. What is your cylinder made of, what is the diameter, length and what size wire are you going to use?

[@RimstarOrg]

Thanks. Sounds good. Our "Radio Shacks" (called The Source here in Canada) are lacking in basic electronics parts but it varies from store to store. The stores I went to didn't have any transformers at all.

[@RimstarOrg]

Did you try the transformer both ways? The problem may also be with something else. Do you have a long antenna? If you don't have any radio stations nearby then you'll need a long antenna. I have two radio stations within around 2 kilometers so I can use an antenna that is 3 15 foot wires connected in parallel. Do you have a good connection to ground? Also, check all you connections on your radio.

[@trailkeeper]

The small ones are often seen/used as "audio transformers". Some people might wish to connect low audio sources to a computer sound car, and it's good to use a transformer there also. Other places besides Radio Shack sell the small audio transformers, maby even a 2000 ohm to 8 ohm.

[@RimstarOrg]

Stepping down (or up) the voltage isn't the purpose. The purpose is to do something called impedance matching. My understanding is that the 8 ohm earbuds are too low an impedance (resistance to AC) for the capacitor/coil circuit. Since they're such a low impedance too much current goes to the earbuds and not enough stays with the cap/coil circuit to resonate with. So we put a high impedance on the cap/coil side. Meanwhile the energy still gets transferred through the transformer.

[@TimpBizkit]

The low ohm earbuds will sag the output stage voltage of a crystal radio so you need to convert some of the voltage into current. I'm not sure why the 1:1 transformer would work any better though.

[@daleburrell6273]

...that's absolutely RIGHT-!!

[@daleburrell6273]

@@TimpBizkit ...to get maximum POWER transfer, it's necessary to MATCH IMPEDANCES: the crystal radio output has a HIGH impedance- while the earbuds have a LOW impedance. Using a transformer is ONE way to match impedances.

[@daleburrell6273]

@@TimpBizkit ...a 1:1 transformer wouldn't do any good as far as matching impedances.

[@RimstarOrg]

(... continued) But notice that the diode and earpiece are also connected to the capacitor/coil circuit. So some energy is siphoned off there for listening purposes. A normal crystal earpiece is a high impedance device (think resistance but for AC) so it doesn't siphon off too much energy. But an iPod earbud, for example, is low impedance and would take too much energy from the resonance, preventing the resonance from happening and so you wouldn't be tuned into one radio station. (continued...)

[@RimstarOrg]

Thanks. Cool, and innovative use of different parts. Re the trip, I've arrived after eight hours driving. No workshop so expect mostly computer generated material in the next few videos.

[@robinbrowne5419]

I'm glad I watched your video. Thank you. I have collected the parts needed to make my first crystal radio by cannibalizing old transistor radios from Value Village (about $5 each). This includes various ferrite cores with their windings, tuning capacitors, several diodes, several pairs of earbuds which measure around 25 ohms, and the earphone jacks which are awesome to have. Now I see that I will need to find a suitable transformer. The hunt through Value Village is back on, looking for stuff that could have a suitable transformer. Then I will mix and match the parts using cardboard, hot glue and my trusty soldering iron until I have a radio that works. I am honestly not expecting it to work first time, but to be a learning process and a fun and interesting hobby. PS - It does seem a little silly to destroy perfectly good radios to make a crappy one, but that is the name of the game. Cheers from Canada :-)

[@RimstarOrg]

Yup, in the comments to my "How to Make/Build a Crystal Radio" video around Nov 10. That's why I mentioned you in the intro. Thanks for pointing out that this works.

[@RimstarOrg]

What do you mean by "handset"? I get asked a lot if people can use their earbuds, for example, their earbuds for iphones and ipods and so on, because that's all they have. If by handset you mean they should use something else then that's not usually an option for them.

[@RimstarOrg]

Here in Ontario, Canada at least, Radio Shack was bought by The Source and I checked all the local ones - no transformers. The local electronics store had only the doorbell transformer. One other electronics store has them but I won't be able to get to them for a while. I would have liked to try the smaller ones you're talking about but I did well with what I had. Let me know how it goes.

[@RimstarOrg]

I think you're referring to magnetic earphones. They're what everyone used to use with crystal radios before piezos came along. I notice all the books still assume that's what everyone has but they're harder to find, even though, as you say, they work better. I have on my list to try to make one someday.

[@kevinleebailey]

an old telephone handset speaker (receiver) work's well 300 series are the best I've tried.SD 150 are OK as well.

[@newq]

An interesting idea for a future video might be showing us how to wind our own transformers.

[@RhetteLawe]

Actually you can use wall adapters that have AC to DC stuff listed on them, but you have to pry them open to get at the diodes. IF you're into deconstructing and re-purposing, sometimes rectifiers they have in the wall adapters can be used in a crystal radio.

[@RimstarOrg]

RhetteLawe Interesting. It's always nice to find a new source for parts. And I do have a bunch of them. Thanks.

[@soonersciencenerd383]

+RhetteLawe I always keep the transformers, to scrap the metal, recycle the plastic, and either put the huge wires in my copper box, and the smaller wire coils, unwind, and use that wire for crystal radio coils. works great!ive used several tubes for coil forms- ink pen, plastic medicine bottles, chapstick tubes, cardboard mailing tubes, and packing tape cardboard! the medicine bottles and (sometimes) the chapstick tubes are the best, but im trying other sizes, diameters. any ideas?

[@RhetteLawe]

Ehh.... it depends somewhat on exactly what you want. round is an easy thing but most transformers are more square. E/I transformers generally require you to either wrap directly onto the transformer, or use something like plastic so that it can be pried onto and off of the sections. This is largely because of the Square geometry in the transformer, but, to be honest, round works just as well if you're doing your on custom inductor. As far as that goes, Antenna shape can help tune the crystal radio, but you have to know what station you want and you have to build the antenna to match the shape required by that frequency. Wikipedia has some good information on antenna shape.

[@soonersciencenerd383]

thanks!

[@RimstarOrg]

The purpose isn't to step-up the weak signal. I think the general purpose for the transformer for purposes of impedance matching but I don't understand it well enough in those terms to explain it that way. The purpose, as I understand it, is to not interfere too much with the resonance going on between the tuning capacitor and tuning coil. The capacitor and coil are exchanging energy back and forth at the radio frequency you want to listen to. (continued...)

[@daleburrell6273]

...you summed it up pretty well!!!

[@RimstarOrg]

Most crystal radio's don't have a lot of power so I would expect it to be able to power only on earbud. If you got one earbud to work then that's great! If you want the other one to work too then you'll need to add an amplifier instead of the transformer.

[@guillermosempron5776]

Put in series.

[@RimstarOrg]

What do you mean by doesn't work. What are you trying to do. What have you done. I need more details about what doesn't work.

[@RimstarOrg]

Oh, neat idea taking apart the AC to DC wall warts. Why not, we seem to take everything else apart! :) I'll have to add an annotation about the 1:1 transformer to the video.

[@mnpd3]

I've used audio transformers to match crystal radio output to the 8-ohm earphones/headphones of today. It works. The problem is that any audio transformer I know of has its own internal attenuation of the heard signal. So, there is a performance cost to using an audio impedance matching transformer. If all ya got are low-Z earbuds, then impedance matching becomes necessary to hear anything. However, I've never found a performance substitute for using hi-z earphones to receive the crystal set's inherently hi-z output. A good quality 2,000 or 4,000 ohm magnetic headphone set should outperform your transformer/stereo bud getup. Since the old magnetic phones are scarce these days, use a huge piezoelectric element with a 10k or 11k resistor shorted across the piezo's terminals. That's about as good as it gets.

[@daleburrell6273]

...that's the truth- there ARE losses associated with using transformers-!! It's equally true that using the 10k-11k shunt resistor wastes SOME of the signal.

[@daleburrell6273]

I just remembered: there are TWO integrated circuits specifically designed for this kind of application: the Ferranti ZN414, and the perhaps easier to find, MK484. These 2 IC's have 3 leads, they look just like a small transistor, and they can be powered by a single 1.5v battery. The information about using these IC's is readily available on the internet.

[@RimstarOrg]

Ah, a broomstick has around the same permeability as air but has a much smaller diameter than the cardboard tube I used. According to my rough calculations (real world is always a little different) and assuming your wire has a thin enamel coating and not thick plastic and assuming you're using a capacitor with a similar capacitance range as mine, then for 26 gauge wire I'd recommend at least 150 turns. I don't know for 30 gauge but I'd go with more than that, maybe 200 to 250.

[@power-max]

I'll keep a lookout. I do have a lot of parts from old motherboards lying around, many in which deal with signals from antennas and cables.

[@RimstarOrg]

Good idea. I actually got the earbuds in the video from a dollar store. Had I thought of it I should have picked up an extension cable at the same time. :)

[@RimstarOrg]

+Raul Rifaie Ronney See starting at 2:12 in the video.

[@aftershock2222]

Crystal ear pieces are expensive, and the last two I have bought don’t work. This transformer method works great. I can now use the ear pieces from the dollar store. Thanks!

[@daleburrell6273]

...the crystal earphones MIGHT need a shunt resistor in order to work-(!)

[@RimstarOrg]

I really can't say without trying, though it's pretty close to my 120v to 6v, so I suspect that if your crystal radio works then it should work.

[@trailkeeper]

I think Radio Shack sells a small transformer of 1000 ohm to 8 ohm, it will provide a theoretical current increase of 125, but the voltage will decrease by that amount also, nonetheless, about the same power is delivered to the 8 ohm earphones as put into the transformer. This vid is a good idea, if I can, I will make a box with one or two of those transformers in it, maby connect two to make 2000 ohm to 16 ohm or something or allow different options.

[@RimstarOrg]

Well, for 11 you've done very well to get one earbud to work.

[@521cjb]

About that earbud connector - if you attach one input lead to the tip and the other to the ring on the plug, you get both earbuds in series, at twice the impedance.

[@RimstarOrg]

It's not 100% intuitive to me either :). One way of looking at it is the earbuds alone are too big a load on the radio, so a larger load needs to be on the radio side. The other way is as you say, the radio doesn't provide enough current to drive the earbuds so a voltage step down/current step up is needed from the radio to the earbuds. I did try both ways anyhow, and it totally doesn't work with the transformer reversed.

[@Slider2732]

Very clean and clear video...enjoyed that. This idea is good too for the common problem of one earbud breaking. . My fave boost output is a solar panel under my workbench 13W CFL and then out to a Sziklai pair of transistors (C1815 and A733). Not room filling but decent enough for the table with a 0.25W speaker...and the light is on anyway. Best wishes for the trip :)

[@daleburrell6273]

...one thing to remember, is that a crystal radio produces a very small audio signal- and if an amplifier is added to the output- the amplifier will also amplify AC hum, and other noise. The more advanced radio circuits amplify the RF signal AND the audio signal- that's the difference. There's an old saying: "...you don't get SOMETHING for NOTHING!"

[@WrightMatt182]

Pardon my ignorance, but I don't understand why the high voltage side is connected the radio, while the low voltage side is output to the earphones. Wouldn't we wan't the high voltage side output to the earphones to step-up the weak signal coming from the radio?

[@raszelast]

Nothing to do with transformers, but dollar stores usually sell male or female to female 3.5mm jack extension cables. With a pair of wire strippers, these can provide an excellent cheap way to get a decent wire connection to plug in anything w/ a 3.5mm jack into an audio circuit.

[@power-max]

was I the one who gave you this idea? I remember replying to your crystal radio project awhile back, mentioning you could use a transformer.

[@SeanBZA]

Just look for any old Ge non power transistor and use the BC or CB junction of it as a rectifier. Best one is an AF117, as it has a very small junction optimised for high frequency use. In this case it does not matter if it is shorted to the case, as you only need one working junction.

[@power-max]

Well... can you light neon light from a AA battery? no because the battery is low voltage and high amps. Can you light a flashlight bulb with a Van De Graaff generator, no because the bulbs filament required about half an amp flowing. the voltage from the generator just flies right though it without heating the wire. same here. the impedance are far too different. the buds require current flowing, where the radio only supplies low currents and moderate voltages (about 40 volts I think)

[@TEODOR006]

I modified a transforme that I've got from a circuit like in Grant Thompson's video of the metal melter, and connected it to th least turns of the transformer, and now i can hear from my computer speakers!

[@RimstarOrg]

Yup. But thanks for pointing it out. I debated going into it in the video but decided not to. You know me... I can't say what without also going into why, and that would have been a whole different video. :)

[@fidelcatsro6948]

hmmm wonder if the microwave transformer coil could step down those ac signals before the diode and output a small voltage at over one amp! free energy experiment..

[@fidelcatsro6948]

This helped me in 2020 as well!

[@mediaguardian]

The transformer connection was not intuitive to me. I would have thought the low voltage side goes to the crystal radio and the high-voltage (more turns) to the ear buds. Thus you would get an increase in voltage (but decrease in current). Perhaps it is the increase in current that you want instead to drive the ear buds. Jim

[@jaddy540]

Ages ago, there was a design using coils wound on a Quaker oats box.A very long antenna and a galena crystal with whisker-feeler. earphones were old bakelite things. Could pick up very strong signals 60 miles away!

[@RimstarOrg]

That depends on how long an antenna you have. The radio stations that I could recognize were all from around 10 miles or less away. But my antenna was very short, around 12-15 feet.

[@daleburrell6273]

...that was for back when there was nothing better available- nowadays, there's not much sense in "doing it the hard way"(!)

[@thinkingjohn2099]

I must try this with the crystal radio I made with your Instructions recently, I do know at School decades ago I discovered if I got a transformer (a old speaker electromagnet transformer used in valve radios) and just momentarily touch a 9 volt battery across one of the windings this produced a brief momentarily high voltage AC spike output across the other windings, I took this to School and told the kids touch these 2 wires while I applied the 9v DC battery well the poor kid would JUMP from a small electric shock but low amperage so harmless !, I figure even though I used 9 volt DC in it still produces the short burst of high AC voltage output anyway the headmaster wasn't very impressed so I received the Cane ! So with your transformer sure it would match impedance for ear bud but it must be amplifying a bit as well

[@daleburrell6273]

...you're only PARTIALLY right- "impedance matching" and "amplification" are two completely different things!!! What's MORE, playing tricks with high voltages- AIN'T FUNNY!!! AS FAR AS I'M CONCERNED- PLAYING WITH HIGH VOLTAGES- IS AS DANGEROUS AS PLAYING WITH FIRE!!!

[@RimstarOrg]

Thanks. That's on my todo list. Just gotta make a start of it.

[@raulrifaieronney586]

Does it really matters about the transformer I mean it have the transformer you have mention or other transformer will do.

[@rotorrant5867]

The best option is to use a 1k to 8R audio transformer, they really blast because they are way more efficient at audio frequencies. Fun video though.

[@RimstarOrg]

Yeah, I had to use whatever I had on hand. Someday it would be nice to use a proper audio transformer and experience the louder sound. I'm glad you enjoyed the video anyway. Thanks for watching it.

[@RimstarOrg]

Yes, microwave transformers can be very dangerous since they can step-up to a high voltage and still provide a deadly current. Luckily in this case there's no danger of that happening.

[@suryatejas3013]

Can we use a amplifier at the end to make the the sound louder, which can the be played on a speaker?

[@shashwatvishwakarma269]

I think so ?

[@daleburrell6273]

ABSOLUTELY!!!

[@power-max]

After you get back from your trip, you might want to try a 1:1 transformer. it might work, I don't know. I cant because I burnt out the 1N34A diode I had, and cant find a suitable diode to replace it. I tried everything from bipolar transistors (just the base and collectors) to different size color and types of LED's, to giant 6A rectifiers, and small signal diodes from Radioshack. even a few small surface mount diodes from a solar charger. those seem to have the lowest voltage drop.

[@RimstarOrg]

I don't know. I've never opened one up so I don't know what they look like inside.

[@roamingcelt]

Have you tried to connect the center of the head phone to the tap (green) and yes the other two legs to the sleeves (left and right)? This uses both sides of the coil and might allow for both earpieces to power up.

[@RimstarOrg]

I never tried that. Given how quiet the sound was already, I figured it would be even quieter. It should work though.

[@fidelcatsro6948]

wow your effectively stepping down the dc pulses from the germanium diode and ground to a lower voltage higher amp to run signals into the earphones..

[@utsavdaga7590]

Can you explain what the transformer do so it work,please

[@RimstarOrg]

I can't say for sure but I think it's doing what's called impedance matching. This is my understanding of it... If we were to connect the earbuds to the crystal radio directly then the low resistance (really called impedance since the current is alternating current) of the earbuds would take too much current that's needed by the coil and capacitor for tuning in the radio station. So instead we connect the side of the transformer that has many turns of wire, a higher impedance. That way that side of the transformer takes only a little of the current from the crystal radio because of the high impedance. Meanwhile, the other side of the transformer, the low impedance side, is connected to the low impedance earbuds and transfers the signal to it.

[@ChrisLennex-cm8vr]

These little things about crystal radio's are interesting, but apart from the AM frequencies; can a crystal radio pick up FM frequencies?

[@RimstarOrg]

I've heard of crystal radios picking up FM but knowing how crystal radios work, I'm not sure how they do it.

[@ChrisLennex-cm8vr]

@@RimstarOrg ok, can you try looking into it? That kind of subject would sound impressive for a future video.

[@Lechoslowianin]

It is better to use the handset 2 kohm. The transformer has a loss

[@serhatdemir1410]

Thank you for knowledge.But l didnt understand something.At normal transformer boosts the ac signal when we connect the higher coil but you boost the audio out with the low coil of transformer.So how does it work like that??

[@RimstarOrg]

The purpose of the transformer here isn't to step-up or step-down the voltage. It's here for impedance matching. My understanding is that the 8 ohm earbuds are too low an impedance (resistance to AC) for the capacitor/coil circuit. Since they're such a low impedance too much current goes to the earbuds and not enough stays with the cap/coil circuit to resonate with. So we put a high impedance on the cap/coil side. Meanwhile the energy still gets transferred through the transformer.

[@serhatdemir1410]

RimstarOrg Thank you so much.l really develope myself by you about radio electronic.And sorry for my english its not good :D

[@milhanmubin4767]

Can I use the transformer of mobile phone charger? .......Please reply 😢😢 I am your subscriber🙋

[@RimstarOrg]

I wouldn't know without trying it. The transformers I tried were pretty randomly selected so maybe it would work. You'll have to try it to see for sure.

[@Alex-nv7cf]

You should not use the ground contact of the earplugs jack to increase the impedance of the earbuds and so can use both earpiece too.

[@RimstarOrg]

That does sound like fun.

[@chrisbudmelman]

Hey again RimStar, another question... if I had a self powered speaker, could I simply use the above transformer to connect to a male to male 1/8 inch and plug that into the speaker? Looking for a quick way to amplify... ps my girlfriend thinks you are cute

[@RimstarOrg]

Christopher Cole I'd simply do without the transformer and connect the crystal radio's output to the input of your self powered speaker. I do that with my homemade amplifier here kzbin.info/www/bejne/gKWzqKuYhMx1ftk ps Thanks!

[@SuperPhantom991]

Can we take out the transformer from the wall adapter......?????? how????? Pls reply its urgent

[@daleburrell6273]

..I know I'm late to the party- but I saw a circuit in a back issue of Popular Electronics, that used a doorbell transformer, connected to a crystal radio, to drive a speaker(!)

[@RimstarOrg]

Cool. I don't have much of an antenna so the output of my crystal radio isn't very strong but I have heard of radios with long antennas doing that. So it's hard to do but is possible.

[@FixitFox]

Did you try the 1-turn coil in the microwave oven transformer? Seems like that would work best.

[@RimstarOrg]

SniperFox I don't recall if I did, but I imagine I would have. But I wouldn't thing it would work best. The idea with the transformer isn't to transform i.e. step-up or step-down voltages. The idea is to do impedance matching and that single turn probably has a much lower impedance than the earbud. Though as I said, I don't recall if I tried it.

[@FixitFox]

That's interesting... I thought you were trying to get more current with the transformer (by stepping down the voltage). I thought more current would make the ear buds louder (stronger magnetic force inside on the ear bud's coils, F=ILB). I don't seem to understand why we need to do impedance matching.. I still have a lot to learn.

[@RimstarOrg]

SniperFox My understanding is that the 8 ohm earbuds are too low an impedance (resistance to AC) for the capacitor/coil circuit. Since they're such a low impedance too much current goes to the earbuds and not enough stays with the cap/coil circuit to resonate with. So we put a high impedance on the cap/coil side. Meanwhile the energy still gets transferred through the transformer.

[@RimstarOrg]

Unfortunately I'm preparing for a trip today and then will be away from my workshop for a month, so no more experimenting for me for a while. :(

[@tehcno007]

its wonderful work that you are doing sir, i am definitely going to make this one .......i am stll collecting parts ....i also want to use it as a morse code reciever.....just because i like morse code.......

[@RimstarOrg]

Oh, cool. Thanks for the tip.

[@Federation_Open]

Hello rimstar! I got transformer for the halogen lamps, he has 230v 50-60hz in and 12v out, will it be useful for this? he has two wires in and two wires out,his power is 50w

[@adat5612]

Hi, I am a begginer who wants to make a crystal radio. I have a few questions if you don’t mind. What did you use for antenna and ground? Also I have a 120 240 AC AC transformer, do you think that would work? lastly, do you know any antenna types that I can use inside home? Thank you!

[@RimstarOrg]

I have this video showing the making of this crystal radio where I show what I use for ground and antenna kzbin.info/www/bejne/jKLHlIhvirF0oqM and in this video I give a few more grounding tips kzbin.info/www/bejne/fou9nn6Qf9d8jZI My antenna was fairly short and may have worked because I have radio stations nearby. I can't say for sure whether or not you 120 240 transformer will work, that's only a 1 to 2 ratio whereas mine was 6 120, so a 1 to 20 ratio. But you can try and see what happens. I also have this crystal radio playlist that has a lot of helpful videos kzbin.info/www/bejne/jKLHlIhvirF0oqM&list=PLFsZmHTZL-zlSltC6ELZW9PK4ks7wgPRz

[@adat5612]

@@RimstarOrg Hi, thank you so much for the video and reply, I made the radio and it worked!

[@RimstarOrg]

Excellent! Thanks for letting me know. I often help people before they get it working but don't often hear back after they succeed. So thanks!

[@power-max]

One more thing. From my memory and past experiment, I found that smaller transformers work better, especially ones with ferrite cores. I wonder if the impedance difference is much greater, how this will effect the performance. can you you try something like an ignition coil or flyback transformer? maybe a transformer from a bug zapper or a electric fence charger?

[@daleburrell6273]

...the transformers you mentioned would be unsuited for this application-!!

[@power-max]

@@daleburrell6273 Ferrite transformers should work fine. Ferrite does have a lower permiability and lower saturation current at low frequencies, but the signal levels we are dealing with are so weak that I don't think that matters. Just have enough turns to provide a really high magnetizing inductance for the primary. That might be challenging though if the ferrite transformer features an air gap or if the core is actually powder core with distributed air gap. The minimal amount of hysteresis may help improve linearity for small signals. Not sure about the bandwidth though.

[@TheBuggy73]

Try to connect the earbuds in series. It might work with both buds.

[@RimstarOrg]

Oh wow! Very cool.

[@joelrubin5319]

Before I break open a pirate iphone charging cube to harvest the transformer for this project, is it an issue that that transformer is used to go AC 120V to DC 5V?

[@RimstarOrg]

Mine was AC 120V to DC 6V so yours should work too. It won't be ideal like mine wasn't ideal since it's not an audio transformer but it worked well enough for me.

[@power-max]

well when i mentions wall warts, AC to DC ones work with modification. I guess I wasn't clear on that. AC to DC adapters were the only ones I had. I just take them apart to get the transformer out. I think what would work best is is small impedance matching audio transformer. even though the impedances are different, the voltage input/output is the same, I believe, I'm not sure. i made the mistake of calling this a 1:1 ratio transformer. sorry.

[@TheCambris]

Thanks for sharing!

[@fidelcatsro6948]

hi there, what if you used a bike ignition coil? mine has a 10k resistance on the high voltage and only one ohm on the low voltage side!! I reckon the higher the resistance the better it will be? afterall a true crystal set earbud has several kilo ohm resistance?

[@RimstarOrg]

+fidel catsro I'm not familiar with those coils, but give it a try. You're actually trying to match the impedance of the tuning circuit side (the tuning capacitor and tuning coil) and the earpiece side. For earbuds it's pretty low, around 10 to 20 ohms, but I don't know what the impedance is of the tuning circuit side though it's higher.

[@moterdude1959]

I just wanted to say I tried my crystal radio with your transformer idea with a amplified computer speaker and it was no louder than without the transformer. It was the same volume pretty much. I also thought with the amplified speaker connected to my crystal radio it would be much louder but it really is not. Any idea for an amp that will make it loud enough to he heard across a room with out things needing to be silent in the room?

[@RimstarOrg]

+moterdude1959 That's odd. Though if your speaker really has a built in amplifier then it should work fine without the transformer (no need for a transformer in that case.) I do that here with my homemade amplifier kzbin.info/www/bejne/gKWzqKuYhMx1ftk. I don't know enough about your speaker to say if it should work. Is your speaker getting power from somewhere?

[@moterdude1959]

The computer speaker I used uses usb port to power it. I modified the speaker to make it more portable. I removed the extra speaker and also wired in a 9v battery cap. I should have used the computer to power it and if the results were not great I would have not modified the thing LOL The volume control seems to light up as bright with the battery as it did when plugged into the computer usb port. The 9v battery maybe more power than what comes out the usb port. I will try building your Amp I think I have seen it online.

[@RimstarOrg]

+moterdude1959 To help with your searching, my amp is here rimstar.org/science_electronics_projects/make_crystal_radio_amplifier_for_speaker.htm.

[@daleburrell6273]

@@RimstarOrg ...that's a very effective amplifier circuit!

[@mayad8509]

one to one transformer could work if fixed coils for buddz or not but with potentiometer

[@bobhs1605]

Would the transformer in a cad player work?

[@RimstarOrg]

I don't know. You'd have to try it, that's the only way I know to find out.

[@viki2133]

Is there a way to hook them without the amplifier and with something cheaper?

[@RimstarOrg]

viki2133 Yes. The amplifier would go where the earpiece normally goes. I show how to make an amplifier for a speaker and use it with a crystal radio in this video here kzbin.info/www/bejne/gKWzqKuYhMx1ftk You may be able to use iPod earbuds in place of the speaker, but I haven't tried that. And in this video I show how to make one for a crystal earpiece, but I don't know if it'll for with iPod earbuds kzbin.info/www/bejne/mYKQfauDedd3ldE And, you can buy mini amplfiers as well.

[@renekenshin6573]

Order a switchable audio matching transformer box from ebay, it works much better with an output power enough for a small speaker. Just imagine listening to a 24x7 power free radio XD

[@RimstarOrg]

Thanks. I really should order one someday. For this video I wanted to show using miscellaneous transformers, but even then it would have been nice to show an audio transformer in use.

[@TimpBizkit]

I'm surprised you could hear a speaker being driven by a passive crystal radio when it's very quiet even with headphones. You say small speaker, but an enormous horn speaker like an Altec Voice Of The Theatre would probably give you the best chance of it getting heard. Also using a long antenna is best.

[@dhruvshah7488]

Can this work from the crytal radio amplifier.

[@RimstarOrg]

I haven't tried but it should. You wouldn't need the transformer if you're using the amplifier.

[@moterdude1959]

That is very interesting that would work. Can it power a regular pair of headphones also?

[@RimstarOrg]

+moterdude1959 I'm not sure. There may not be enough current.

[@moterdude1959]

I had one more thought with the transformer hook up. The way you say to hook it up you would think would be stepping the power down from the 120v side to the lower side. Would it work if you reversed it so the radio was feeding the lower side and feeding the earbud with the high side. Just a thought I am going to try the transformer. Thanks for your videos and your reply also.

[@RimstarOrg]

+moterdude1959 I don't think its purpose is to act as a transformer, stepping up the voltage. I think its purpose is for impedance matching. That's why it works better the way I've used it. But try it the other way anyway.

[@moterdude1959]

OK thanks again for your reply I was just wandering. I will try it soon for my self to see how it works.

[@moterdude1959]

I did the test of reversing the transformer and it did not work at all. When properly connected it did work the head phone but was not loud enough as my crystal earphone on there own. With transformer it did not work when I connected the crystal earphone. The transformer worked like you said. It all was very interesting to try. I am going to try the computer powered speaker next with your transformer to see how that works. The powered speaker was not as loud on its own with the crystal radio. I am hoping with the transformer it gets much louder. I will let you know how it works out.

[@Slider2732]

Should have taken a map LOL, only joking. Thought you would be taking a break, so it's great that you'll be posting vids. Ah, there could be ideas from the local environment...I know what you can do with a Coke can ! :)

[@power-max]

OH, wait, I didn't hear you say it in the video until just now. sorry about that. ;) i thought at first you simply stated "some user pointed out"

[@RimstarOrg]

You're welcome. Do you mean you used this transformer trick and got your speakers to work? If so, cool. If not, still cool. :)

[@tanimadattaroy6266]

Can l use any type of transformer sir ?? Please reply sir, please

[@RimstarOrg]

I don't know what type of transformer is best. I strongly suspect that an air-core transformer would not work well. I think I recall trying a few that I had laying around (e.g., I also tried a big microwave oven transformer) and the one in the video worked best. It's a doorbell transformer, normally used for converting the household 120VAC to 12VAC for powering doorbells. I'm sure if I knew the calculations, I could figure out an ideal one.

[@tanimadattaroy6266]

Thank you sir

[@lindseyg1670]

do you need those clip things to attach the transformer?

[@RimstarOrg]

No. Attach it anyway you can. There are many ways. Just make sure you have a good connection.

[@daleburrell6273]

CERTAINLY NOT! The "alligator clips" are used because they are a simple, versatile, and convenient way to make electrical connections!!

[@subhashdas5560]

Can I usee 220-240 volt input to 12volt output Transformer

[@RimstarOrg]

That will probably work. 12 volts to 220-240 volts sounds very similar to the one I show at 4:00.

[@biraggodinho7635]

( transformer 220V / 3V 200mA or 250mA ) = ( 586 Ohms / 8 Ohms ) good sound.

[@itisonlyadream]

I had to check the posting date of this video to see if this was an April Fools gag. When he put the earphone up to his phone I couldn't hear anything but a loud background hiss after I turned both the youtube volume and my speaker volume all the way up to maximum. I really had to laugh when he took the earphone away and commented about how strong it sounded. Strong, it wasn't even audible! Then, I searched the comments to see if other people were complaining about the fact that the crystal set had no audio output and I couldn't find a single complaint about it, but there sure are a lot of comments from RimstarOrg. If anyone else actually heard this thing, then I must be going nuts, because I'm sure not deaf. And what up with using doorbell transformers and 60 Hz AC power transformers for impedance matching? I've used audio transformers for impedance matching crystal sets to low impedance headsets, but an AC doorbell transformer? And, the fact that he would even consider using the transformer out of a microwave oven was so over the top that I knew I'd been had. Welcome to Looney Tunes folks and be sure to try the Kool-Aid.

[@RimstarOrg]

I just relistened to the video and I can hear it. It's not as loud as hearing it in person but I can make out a voice sound which is distinct from the background static. As for the selection of transformers, it's a matter of using what you have around and can find locally. It's not ideal, which is why I mention audio transforners.

[@itisonlyadream]

@@RimstarOrg In the interest of due diligence, I listened to your video again, only this time I used Chromecast to send the KZbin video directly to my TV set, because the TV has a better sound system than my computer. I turned the audio up until your voice almost hurt my ears, but when you held the earbud up to your phone all I heard was a constant background noise until you took the earbud away and started talking. Then, I felt really stupid for falling for your s**t twice. But, if I smoke some of that stuff you're smoking, then maybe I'll hear the radio in the video too. The Piece de resistance was when you commented about how strong the audio was, that added a nice "comic" touch. As for the selection of the transformers, I understand the concept of using what you have on hand. I do that myself, but some parts are suitable for some things and some parts are not. It was the unsuitability of the transformers you used that I commenting on, it wasn't because they were parts from your junk box. Speaking of unsuitable transformers, I had to laugh out loud when you used the high voltage transformer from a microwave oven with a crystal set, that was the highlight of the gag for me. I don't know if you were really able to hear anything in that ear bud, or not. But, I'll bet money there's no detectable audio from the earbud in the video. You're probably laughing your ass off, because you got me to watch your video again. I may be a sucker for giving it a second chance, but you can't say I didn't give you a fair shake.

[@jomona9783]

Thank you for sharing this video

[@lindseyg1670]

Can I use a audio output transformer that i got from RadioShack?

[@RimstarOrg]

Yes. I've never found one myself, but those should be ideal.

[@marcosyreme]

Good idea

[@TEODOR006]

glad you liked it!