Hi guys. I have this circuit where the clipping section should have a pair of germanium diodes but instead it has a Red led and a yellow "diode"? I'm trying to identify what this diode is but with no luck.
Looks like a cap to me. Are there any markings on it?
(http://ww1.prweb.com/prfiles/2015/07/16/12813713/gI_115817_20128291428484681.png)
Certainly has the look of a dipped axial cap.
Poke it with your DMM, see what it spits out. Does it have a voltage drop on diode setting? Does it have a resistance that is different in either direction? Does it have a capacitance? Readings in-circuit may be a bit odd, but it can give some data at least.
Wow, I think you are right, it is a cap!!! That is mad. This is a Fuzz War, 3 knob version, from early 2017. Not sure if they are all supposed to be like this, but that cap is very surprising to me.
It's intriguing. Would two Germanium diodes be a close equivelant to one Red LED clipping wise?
Quote from: garfo on November 29, 2018, 11:26:21 PM
It's intriguing. Would two Germanium diodes be a close equivelant to one Red LED clipping wise?
Not really, Germanium diodes have a fv of less than .5v typically, and red diodes are around 1.5v.
To add to the mystery, the part number listed on the pcb in that pic is for a Zenner diode, not germanium.
True, regarding the diodes, but the other circuits that have been traced, that I have found online, report to have two 1N34A.
I did find this in an old Geofx aritcle:
http://geofex.com/Article_Folders/TStech/tsxtech.htm
"The small 51pf capacitor across the diodes acts to soften the "corners" of the clipped waveform somewhat. This softens the distortion somewhat. The action of the 51pf is most noticeable when the drive control is maxxed out, so it softens the distortion most when the gain (and distortion) is highest. Put another way, the capacitor's impedance goes down with increasng frequencies, so it starts cutting the gain of the stage when the impedance of the capacitor is equal to the resistance of the 51K resistor plus the setting of the drive control. This rolloff frequency is lowest in the audio range and most noticeable when the resistance of the drive control is highest. "
One of the characteristics of germanium over silicon is it is a bit "softer", so perhaps this was an oddball attempt to sorta kinda emulate that, but keep the volume and punch of an LED clipper.
Somnif, thank you for showing me that article. You might have solved the mistery :D I will socket these two and experiment and AB it with the original.
All the Fuzz Wars I've seen have the Ge diode pair. This might be a way to cheap around not using them.
How does it sound?
Quote from: Torgoslayer on November 30, 2018, 04:55:45 PM
All the Fuzz Wars I've seen have the Ge diode pair. This might be a way to cheap around not using them.
It's possible. It's a NAMM edition, apparently onw out of 50. It sounds really good in my opinion, but it's really hard to compare cause it's the only original I've played.