More Mystery Diodes

[Ben Lyman]

Okay, so this time they really are diodes!

The first came in an old bag labeled Hewlitt-Packard 1902-3333 CD3 Diode, 46.4V and two of them sound great at the end of a FF, tons of compression and endless sustain. On a diode tester they say 790 one way, nothing the other, beyond that I don't know anything about them.




The second came off an old circuit board, maybe mid-1960's, I know nothing about this one at all except it reads 260 on my diode tester.
EDIT: I just pulled a second one off the board and popped the two in place after the FF output cap, again more great compression and sustain, makes to FF go into BMP territory. Also, they have a marking, maybe "G I" or "G 1"

[anotherjim]

I suppose there's the chance that HP have or had so much buying power they could have their own part numbers. 46.4V rings a bell - a transient protection device (or TVS) Zener thingy. Can be used as a normal silicon diode in low voltage circuits. 

The other is a germanium point-contact diode. Note the pig-tails formed in the leads - a good way to isolate the body from mechanical stress and soldering heat. Beware excessive current when experimenting with these, they are probably quite .

[GibsonGM]

Interesting pigtails - do you suppose that creates some additional capacitance??  Not that it would amount to anything much, but hey - could be a 'mojo' thang!

[R.G.]

Interesting pigtails - do you suppose that creates some additional capacitance??  Not that it would amount to anything much, but hey - could be a 'mojo' thang!

That's the premium way to make components more vibration proof and heat resistant, as AJ says.

[duck_arse]

oddly, my first boss advocated a single twirled lead for zener diodes. the hp bag number has a motorola part within - what do we read into that?

I found this :
http://www.ebay.com/itm/1N3998-6-2V-10W-Zener-Diode-HP-1902-1217-New-/380499779208

which has the first four bag numbers match, but .... it doesn't look like you have 10W stud mounts there.

[ashcat_lt]

Interesting pigtails - do you suppose that creates some additional capacitance??  Not that it would amount to anything much, but hey - could be a 'mojo' thang!

Looks more like an inductor to me.    Course, since the leads aren't insulated, if the coil is tight enough to touch itself, the whole loop would be shorted and not do much at all electronically.

[Ben Lyman]

About half the pigtails are touching on the board, half not touching.
I couldn't really see the color bands until I looked at these pix and I'm slightly color blind but it looks like red/violet/blue. 1n276 I presume. Whatever they are, they sound fantastic as added compression and distortion to my FF. I don't even know what you call it when you put two diodes in opposing directions from output to ground but that's where I put them.
On the grey HP diodes I noted that Motorola "M" that looks like two Star Trek logos.
On a side note, I'm still waiting for an answer to my latest FF query in this thread:
http://www.diystompboxes.com/smfforum/index.php?PHPSESSID=5213c22ac72b067e8be019723b8bad54&topic=112427.0
I don't want it to drift into the void