Sorta OT - CIL 1301?

[Paul Marossy]

Anyone ever heard of the diode before? I'm trying to figure out what kind of diode it is. I can find no information on this thing, at all.

It is on one of the cathodes of the preamp tube on the High-Gain Hybrid module for the Seymour Duncan Convertible, in a back-to-back configuration. I asked this question over at Ampage a couple of years ago, and the consensus seemed to be that it was probably a small signal diode like a 1N4148, but then some people thought it could be a zener or even a schottky diode. I figured someone here might know what this is, I hope?! It looks like it's just supposed create some hard clipping and as Seymour Duncan claims, more odd order harmonics.

An image of it can be viewed here:
http://www.diyguitarist.com/Images/CIL1301.jpg

I drew up a schematic and module layout for it, too:
http://www.diyguitarist.com/PDF_Files/HG-Hybrid.pdf

Anyone?

[Jason Stout]

what is the forward voltage?

[Paul Marossy]

I dunno. I never measured it... I suppose that could give me a clue, huh?

[Peter Snowberg]

Since they're cathode to cathode..... they've got to be zeners. They won't be schottkys or small signal diodes as those would both look like an open circuit until one of the diodes fries.

Measure the voltage from the junction to ground as the amp runs to see what the zener voltage is. The voltage across the other diode (the one going to the cathode) will probably look like a Si power diode (maybe ~.55-.6V).

Take care,
-Peter

[Paul Marossy]

Yeah, my gut feeling is that they are zener diodes. That makes sense somehow. Problem is that I don't actually possess that module, so I can't measure the voltage on it.  
That PCB layout and shematic were derived from pictures of a module that someone sent me to look at to create the schematic. Once in a while the mystery diode returns to the forefront of my mind and I make another attempt at trying to figure out what the heck it is. I should probably take one of my high gain modules and experiment with sticking some different diodes in there.

If you had to guess, what range do you think the voltage range would the zeners be set at? I suppose the higher you go, the less clipping will occur?

[Paul Marossy]

Ansil wrote me an email on this diode a few days ago, and so I'm hoping that someone might be able to add something to this. I have been wondering about what this particular diode is for quite a while now...

Zener diodes still seem to make sense. I'm still am not sure what voltage they are likely to be, though. Anyone?