Identifying MA856 diodes

[Miracle Man]

Hi!

I was hoping some of the more knowledgeable forum members could help me out. I've been thinking of building a KOT clone recently, and the MA856 diode is obviously very hard to get a hold of. However, I've found some similar looking diodes on an old telephone PCB. Is there any way of identifying these? I'm mostly into modding amps and don't have much experience with pedals     They look like MA856 diodes I've seen in pictures, but I suppose there could be other similar looking diodes. Any help will be greatly appreciated! 



Sorry for the quality of the photo, I used my cell phone to take it.

[midwayfair]

Those are a fairly generic package, the DO-35. Many, many diodes look just like that.

[Pyr0]

Good luck trying to identify them visually  

Here's a pic of 3 I have, never could find another 5  
The bottom diode in the picture is a 1N914 just to show you how similar they are.



It's best to measure the Vf, MA856 should have a Vf of approx 0.90v, at least they do when tested on my DMM diode function.
They were originally used for band switching in radio and tv tuners, so look for that type of diode.
Looking at data sheets for various other band switching diodes and comparing some basic Vf tests on a DMM diode setting, the BA278 and BA243 are very similar to the MA856 and have very similar specs on the datasheets.
I have a some BA243 with a Vf of 0.94 and also BAS33 with a Vf of 0.92 to 0.95.
All of these have similar capacitance to the MA856 and were used in similar high frequency circuits.

So use some of those alternatives, I doubt your ears will be able to tell the difference. Capacitor tolerance would have more of an effect on sound.