Madbean Serendipity vs. ZehnDrive and La Revolution Deux Schematic

[tcreverb]

I recently built a Zehndrive kit from MEK Electronics in the UK.  I compared the schematic to that on the La Revolution Deux DIY Pedal site and it matched.  I notice on the Madbean Serendipity schematic that diodes D1, D2 and D3 are in the exact opposite locations of the other schematics.  For example, coming off the "-" of the IC1A, D1 and D2 feed into Q1.  On the other schematics, D3 feeds in to Q1 and the diodes in series feed into Q2.

Which version is correct?  The Zehndrive kit version sounds great, but I'm wondering if the Madbean version is also correct and which one is more accurate of the original "Zendrive".

Thanks in advance.  I'm new to the forum by the way and appreciate the value of the site.  This si my first pedal project and I am happy that it turned out for me.  Sounds like an OCD or Fulldrive almost but I like the way it sounds at lower gain settings better.  Very similar though.

[jkokura]

Can you post links to the thing schematic or kit you're talking about?

Jacob

[tcreverb]

Here is the link to the Zehndrive.  Click on Manual to see the schematic in the pdf file.

http://uk-electronic.de/onlineshop/product_info.php/products_id/1211?osCsid=4bd25c9216ff4793a9b3479e9a54aae3

Then compare that schematic with the Serendipity version of the Zendrive.

http://www.madbeanpedals.com/projects/Serendipity/docs/Serendipity_ver.5.pdf

Compare the diodes/Mosfet sections and notice that they are reversed on the Serendipity vs. the "Zehndrive".

Are they identical electronically?

[mgwhit]

Yeah, the arrangement of the diode/MOSFET clipping is identical electronically, although I notice that the ZehnDrive uses a Germanium diode in one position, where the Serendipity uses another BAT41.  That just increases the asymmetry of the clipping a bit (and might give you some mojo  ).

[DutchMF]

Comparing the schematics, I think it's just a matter of which part of the signal (neg or pos part of the sine-wave) goes through the double or the single diode? Do I have that right? I presume the end result, soundwise wouldn't be to different. The gain/drive pot and its resistor are mirrored as well.

BTW: I just loved the mix of german and english (if it was english...) in Das Manual! Haben Sie ein vorverdrahtete Inputbuchse fur mich? 

Paul

[tcreverb]

Thanks for the replies.  The pedal sounds good to me.  Maybe that's it, the signal is just negative or positive side.  We'll see if we get any more replies. 

[mgwhit]

I think it's just a matter of which part of the signal (neg or pos part of the sine-wave) goes through the double or the single diode? Do I have that right? I presume the end result, soundwise wouldn't be to different.

Yeah, I think you're right.  Not 100% electrically identical, but probably getting into cork-sniffing territory in terms of sound.  I have no idea how the real Zen Drive does it.