Zendrive diodes

[khm9]

Hii

I'd like to try out the Hermida Zendrive circuit, so I can hear for myself what makes the pedal so sought-after.
Through out my research I found out that there has been a lot of speculation on which parts the original units used, because the markings on the most important components were sanded off.

I've narrowed down my choice of the opamps I'm going to try, however, I am not sure which diodes to use.

Various sources suggest that some Zendrives used 3x BAT41 diodes, while some 2x BAT41 and a 1x germanium diode which has adds additional confusion.

On the screenshot below, I marked the diode in question.


If I'm not mistaken, the diode in series is used to achieve "asymmetrical clipping".

Is the germanium diode going to affect the overall sound of circuit as opposed to using all BAT41 instead?
If you've built a version of the Zendrive circuit, which diodes have you used, have you liked the end result?
From a technical aspect, does it matter which diode is used to achieve the asymmetrical clipping?

I will most certainly breadboard the circuit and try out the diodes in question and choose the one I like the most, but I'm afraid I might like them all... 

[Rob Strand]

As far as the schematics go it's all a big mess.   

The most believable info for the 3-diode version is D1 = germanium (1N60/1N34A), D2, D3 = Small signal Schottky.

Another variation is the which polarity has the extra diode.   Most believable info is the extra diode on the clipper when the output is negative.  So your schem has the diodes and MOSFETs flipped.

I'm fairly sure Alfonso's pedals have had some changes over time.  The earlier incarnations before Zendrive existed had two germanium diodes D1 short, D2 ge, D3 ge.


I believe he has always connected the MOSFETs with g to d.

(I'd have to consult my banished archives to see if I have any more info.  I know I looked at it at some point.)

[khm9]

Another variation is the which polarity has the extra diode.   Most believable info is the extra diode on the clipper when the output is negative.  So your schem has the diodes and MOSFETs flipped.

Interesting. Most schematics I've looked at have the diodes and the transistors flipped like in the screenshot. Very few of them have it the other way around.
Could there be two variations of the Zendrive or has one of the schematics gotten it wrong?

[Rob Strand]

Could there be two variations of the Zendrive or has one of the schematics gotten it wrong?

I know I've looked at this is in past and I'm sure one of the schematics is wrong.   Anywhere where someone has to bother getting the details right, there's always a stuff up!  That's the way of the web.

The trusted traces come from Martin Chittum (the guy who did the correct Klon schematic) and Aion.
https://aionfx.com/project/azimuth-dynamic-overdrive/


Here I'm screwing stuff myself,

Corrected
"I believe he has always connected the MOSFETs with g to d."