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IEM for crystal radio use

cistercian

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I went a bit nuts after I discovered how sensitive low impedance IEMs can be using an appropriate audio transformer...for crystal radio use.
This is NOT an audio quality topic. As an inveterate geek I have played with high sensitivity phones since I was a boy. My first radio was a crystal set and used a very high impedance piezo
earbud. I have fond memories of exploring with it and seeing what I could hear depending on what I touched one terminal to while I held the other in my mouth or hand.
I found a couple of decent balanced armature IEM sets that were very good for crystal set use. One is the KZ-ZS16. Sensitivity is just incredible with a correct transformer.
The ZS-10 pro is great for more local work.The best transformer I have found so far is a Dynalec unit that is 100k to 150 ohm with a 16 ohm tap. Great transformer and with the KZ-as16 is epic. The KZ-AS16Pro has better audio quality by far and poor sensitivity in comparison.

I post this for the guys that want an ultimate crystal radio transducer (all 10 of you) because the as16 non pro is the bomb.
Fairradio sales has the dynalec transformer for 15 dollars last time I looked.

Crystal radio enthusiasts use old sound powered naval phones for the best sensitivity...but they are old...and potentially expensive...and you need to be a high order craftsman to restore them.
For a modern off the shelf solution The KZ-AS16 is amazingly good. I have a pile of KZ IEMS now. So plenty of spare cables and of course I have a pile of spin fit tips too.

Which is still easier than putting a magically good headset made from sound powered phones together.

Those who understand what I have written will understand. All others can dismiss it...no harm no foul. Best wishes to all!!!
 

amirm

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Ah, this brings back fond memories. I built a crystal radio when I was 7 or 8 years old and was amazed how few parts could get you to listen to an AM radio. Those piezo earphones were the key to getting it working. Didn't know it was still "a thing" to build these.
 
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cistercian

cistercian

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Ah, this brings back fond memories. I built a crystal radio when I was 7 or 8 years old and was amazed how few parts could get you to listen to an AM radio. Those piezo earphones were the key to getting it working. Didn't know it was still "a thing" to build these.
It is my friend. I was 8 when I got mine. I am 61 now. So when I say these are good I am serious. I hate earbuds BTW. I wish someone...anyone would make good "cans" for this but they don't. The best I found before I went down the IEM rabbit hole is the Sennheiser HD-26 Pro cans. They are absolutely outstanding for AM BCB use for stronger signal use. My "radio" is a 4 foot on a side loop of #15 7 turns. I have heard 23 states and canadian provinces so far with it. I can't wait for winter. Lowest power station was a single hop away with 270 watts WSVS VA I have heard that station many times!

The Sennheiser HD-26 Pro cans are engineer cans for pro use. Very poor for high end audio since they are best for 20 to 10kc or so with a nice hump around 2kc response which is ideal for voice. I cannot recommend them for muggles but for insane voice recovery they are very good indeed.

I use very good tuning capacitors, a single germanium diode, a capacitor/resistor network to match the transformer, transformer and cans for the set.

Comically, the best AM radio I have ever heard in my life is my homemade crystal set for local use.Transformer is a Shure A95U, cans the Senn HD-26 Pros and a 2 ft loop with a diode and RC network. Great for coast to coast AM on the local 5KW station a couple of miles away. It sounds wonderful Amir...no kidding it is great.

The bass and treble it produces is simply delicious. 12 turns of #22 2 feet on a side on a PVC frame is the ticket here in Asheville NC,

Best wishes Amir and the group from your friend in the Appalachian mountains!!!

PS. The Sennheiser HD-26 Pro cans are so niche and weird I certainly do not expect a review. But if you did one it would be a serious public service.
They are Ideal for the typical AM BCB frequency response range. Or to put it another way, broadcast use. Expensive. But sweet if that is what you seek.

There are virtually ZERO good measurements or reviews of them either. Consider this a bug in your ear my friend with the caveat that it is not a HIFI headset.

I hope all is well with you and your family and your garden. :)
 

MaxwellsEq

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This has brought back memories. I built my first crystal set at about 7 years old with my father helping me with the soldering. Even today, I expect most kids would be amazed that something could make sound without an obvious power source.
 

thewas

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Ah, this brings back fond memories. I built a crystal radio when I was 7 or 8 years old and was amazed how few parts could get you to listen to an AM radio. Those piezo earphones were the key to getting it working. Didn't know it was still "a thing" to build these.
Oh yes, lovely old days, just a diode, some capacitance and wire (for inductivity), not even a battery was needed. :)
Also didn't know it was still "a thing" and just read that within the framework of competitions, e.g. the "Annual Crystal Set DX Contest", hobbyists with self-built detector receivers compete for the best receiver and in the 2003 contest, for example, the winner was able to listen to over 190 transmitters at a distance of up to 4000 km!
 
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TheBatsEar

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I built a crystal radio when I was 7 or 8 years old
So did i, in 1980:
extra01.jpg


It was only a year or so later that i pimped my mothers Kassettenrekorder with a car speaker i got from a trash pile.
8b67bdb7-fdbe-48c4-88f2-f45821badb95
 
OP
cistercian

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UPDATE: Like an idiot I bought a KZ AS24 hoping for an improvement over the AS16 because it had double the number of HF BA's
as well as a redesigned mid and bass BA.
It is now my go to for weak signal crystal radio use. In practice the AS24 is about as much better for weak stations as the AS16 is better than
a ZS10 pro X is. A substantial improvement. A few more days of testing should help but so far I find the AS24 much more shouty and better
for weak signal use. An exceptionally sensitive BA IEM. It is a shame it's over 100 bucks a copy.

So far...highly recommended! I will update soon but I don't think my opinion will change. @ 20 ohms you NEED a good transformer like the
dynalec 100k to 150/16 ohms I am using. It's not as pleasant as the 16 to listen to. But it's extremely sensitive. Amazingly so.

I was actually a bit sad to see it crush the 16...Now I have to buy another set for backup. Oh bother!!!
 
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cistercian

cistercian

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Further testing shows the 24 is better in HF response but in fade conditions the 16 beats it because it does not roll off as much as you approach
1 kc. Comically, the 24 is better for finding new stations as hetrodynes are much louder in it. But for voice intelligibility the 16 is better.
In practice...very close. And when signals are strong the 24 has bass the 16 lacks and just sounds epic, But at very low levels the 16 rules.
The AS16 (non pro) can be had for 50 bucks on alibaba as a one time deal. If you are a crystal radio fan buy one. DO IT NOW.

Before it's too late.

I have 4 as16's. I am set.

I hope this is useful for the primitive radio users.
 
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cistercian

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On the #12 wire 8 turn magnetic loop 44 inches per side using the 100k to 16 ohm transformer and a germanium diode from Asheville NC stations so far. No earth ground used. 5 local stations excluded...all of them very close. Antenna facing N/S
650 WSM Nasheville
660 WFAN NY
690 WOKV Jacksonville, FLA
700 WLW Cincinatti
710 WOR NY
720 WGN Chicago
740 CFZM Toronto, CAN
750 WSB Atlanta
760 WJR Detroit
770 WABC NY
780 WBBM Chicago
840 WHAS Louisville
850 WKNR Cleveland
860 CJBC Toronto
870 WWL New Orleans
880 WCBS New York
890 WLS Chicago
920 CKNX Wingham, ONT
970 WGTK Louisville
990 WNML Knoxville
1000 WMVP Chicago
1010 CFRB Toronto, CAN
1020 KDKA Pittsburgh
1030 WBZ Boston
1040 WHO Demoines, IA
1060 KYW Philly, PA
1100 WTAM Cleveland
1120 KMOX St Louis
1190 WOWO Ft Wayne IN
1510 WLAC Nasheville
1530 WCKY Cincinatti

If you live in an apartment you too can go nuts with a small indoor crystal set!
 
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cistercian

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I should mention that in practice I have had excellent results with the KZ ZSN Pro X. It is very sensitive and close to the as16 but with better
bass. It is very inexpensive for those that want to give it a try too!
 
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