Crystal Radio--A Good 1N34A Diode Substitute (4K)

I've gotten a lot of suggestions for alternatives to the 1N34A diode as a detector in crystal radios. I have tested several, including power diodes like the 1N4007 (not worth showing) and the Schottkey diodes (on the oscilloscope it looks good, but is muffled compared to the 1N34A or D9K in actual use).
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1N34A
Forward voltage drop: 1V @ 5mA
Breakdown voltage: 65V @ 1mA
Reverse leakage current: 30µA @ 10V, 500µA @ 50V
Flat Junction capacitance
Lower leakage current
Absolute Maximum Ratings: (TA = +25C unless otherwise specified)
Peak Inverse Voltage, Repetitive (I R = 1mA), PIV 65V
Reverse Voltage DC, V R 20V
Peak Forward Surge Current, Non−Repetitive (t = 1sec), IFSM 0.5A
Peak Forward Surge Current, Repetitive, I FSR 200mA
Average Rectified Output Current, I O 50mA
Operating Junction Temperature, T J +75C
Storage Temperature Range, Tstg −55 to +75C
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D9K
Maximum reverse voltage U(BR) 30 V
Maximum forward current IF 60 mA
Maximum reverse current IR 60 uA
Forward voltage drop at the pn-junction U(F) 1 V
Frequency range, maximum Fd 100 kHz

[@robinj.9329]

The correct diode used to be readily available at every corner "Radio Shack"!
I likely still have a few bags of a dozen diodes purchassed decades ago!

[@tsbrownie]

They are worth a lot on ebay!

[@marcisberzins]

Not sure, but Д9К could be one of soviet germanium small junction diodes of biggest reverse resistance (subtype 'K' of Д9).

[@davidanderson498]

Where I worked as a technician until a couple of years ago we had a problem getting germanium diodes that worked, probably there were a lot of knockoffs circulating, the older diodes in stock did work.

[@tsbrownie]

Interesting, but sadly not surprising with all the fakes out there.

[@StepDub]

What about the OA79 ? I seem to remember using this device in a crystal set 60 odd years ago.

[@tsbrownie]

"Germanium contact point high-frequency diode, intended for use as detector in FM receivers". There are lots of diodes that sort of work, but give poor sound quality like clipping or low volume. I have not tried this one but it seems made for other purposes.

[@StepDub]

@@tsbrownie I think it was included in the Philips EE kits, which I had. Worked quite well if I recall.

[@tsbrownie]

@@StepDub I'll have to see if I can find one to test.

[@Lechoslowianin]

it is best to check such diodes on a working system

[@tsbrownie]

I agree and I did that. For example, the Schottkey diode looks OK on the scope, but sounds muffled in a radio.

[@franzliszt3195]

So does the D9K sound better than the 1n34a?

[@tsbrownie]

I cannot hear much of a difference. The D9K might have a higher pitch in the same radio.

[@adnacraigo6590]

Where were you able to find your d9k diode?

[@tsbrownie]

I bought them on ebay. (There's a funny song about that from Weird Al Yankovic.)

[@adnacraigo6590]

@@tsbrownie Thank you, sir.

[@tsbrownie]

@@adnacraigo6590 I found my order. The shop on ebay is called "Stavr-shop". I don't know him, but he delivered what was advertised. It did take a while.