Home Forums Show Off Your Build MKC Finished (Almost)

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    Big O

    I finally finished my last kit purchased from Mammoth a couple of years ago, a pretty much stock MKC.  I have been working on it on and off (mostly off) for the past 3 months or so.  As with the more recent adventures with Mammoth, there were a couple of issues with the components.  I received a Mammoth 3PDT wiring board for the footswitch, but no footswitch itself.  One of the capacitor values in the kit was off by 10%, but I had a replacement in my stash so I installed the correct value according to the build document.  However, I don’t know if the 2.2n versus the provided 2.0n would have made a big difference, but I stuck to the build document.  I used the Mammoth provided diodes marked 1n34, but I don’t know they are the real deal Ge ones and am awaiting guaranteed real Ge diodes to substitute.  You can see the temporarily socketed diodes in the gutshot. The enclosure that was provided was drilled in a somewhat unusual way that makes it difficult to find a place for a battery with the footswitch hole being about an 1/8 inch too close to the bottom.  Once I install the know Ge diodes, I will work on that problem.

    Finally, I had some issues with my waterslide decal and it might be the brand because I had the same problem with the same brand decals (LaserTran) with other pedals – don’t apply very easily or stick to the surface well.  This resulted in some clearcoat getting underneath the decal and causing some bubbling, but I will live with it.




    Looks great!

    What makes you suspicious of the diodes? Sound? Measurement?



    Looks good man!  1n34 diodes can come in many different colors and packages.  There is a site called Pedalhacker.com that sells Ge diodes specifically for the Klon (D9E is the model the real Klons use) as well as many different Ge diode models including several 1N34 styles.  Good luck!

    Big O

    Re: What makes you suspicious of the diodes?

    Diodes have around 0.7V forward voltage or slightly greater and do not appear to demonstrate thermal variations in measured forward voltage.  I know there are fake 1n34’s out there, so I am not convinced.  Pedal does sound fine with the current diodes provided in the kit, though.

    Big O

    Finally finished this puppy.  Many thanks to Barry who sent me replacement 1N34’s, confirmed to be genuine working Ge diodes this time by both of my diode testers.  I suspect that maybe the original set may have had thermal damage as they were traveling by mail during the time period of the coldest, frigid spell of the winter this year.  I also reversed the direction of the fat switch as I originally placed it in the enclosure in the wrong direction for the pedal graphics.  This was accomplished easily as I purposely left enough slack in the switch wiring to turn the switch 180 degrees and then re-tighten it. I don’t know why I installed it in the wrong direction at first because I used different color wires to try and keep the orientation correct, but I failed.  You can tell by my original gutshot as the left sided white switch wire from the board is going to the right sided lug on the switch.

    I think the only thing I would change is actually taking out the trimpot for the clean gain and replacing it with a pot mounted on the outside of the enclosure.  I was on the fence about this and wish I had done this at the time of the original pedal build.

    New gutshot with fat switch reversed and 1n34’s installed in the diode sockets.

    Big O

    I did some research on the diode subject.  Apparently the original Klons used 1n34a’s chosen to have a measured forward voltage of 3.5V.  If you have some Ge diodes that have close to the 3.5V measurement, they should be good in the MKC circuit.  Mine measure around 3.2 to 3.4, so I am satisfied.  I have D9* Ge diodes as well, but these have forward voltages slightly over 4, so I guess I could substitute to see if there is any appreciable difference as I socketed the diodes, but that is a project for a later date.


    You could put them on a socketed DPDT wiring board we were talking about before and test back and forth instantly between pairs. Let us know if you hear anything worth reporting or otherwise.


    Big O

    I hate to revisit this, but I tested the approximately 20 Ge diodes I have on hand and found two with a forward voltage of 0.35V (0.350-0.353V).  According to Bill Finnegan, the builder of the original klons, he hand selected two Ge diodes labeled 1n34a that had a measured forward voltage of 0.35V and that is the “magic” he put in his original pedals.

    I took out the 1n34’s in the diode sockets and replaced them with the selected diode pair.  Voila!  There it is, the magical holy grail tone that the owners of $3000-5000 original centaurs talk about.  I am now willing to part with my MKC for the bargain price of $2500!  Act now if you don’t want to lose out!

    Hopefully, the readers of this got the sarcasm.  No, there is no real discernible difference to my musically trained ear (years of playing guitar, saxophone, bassoon and baritone as well as over 40 years of critically listening to music).  Maybe matching the forward voltage of the diodes as closely as possible might get you a little more consistency in clipping, but really is this audible?  IMO, I think not.

    I have discovered that it is probably a good idea to use a external pot for the clean gain.  As opposed to what is stated in the instructions about the clean gain being a subtle effect, I have found to my ears that this is really not so subtle.  The main reason is that with a more distorted dirty gain setting, a louder clean signal blended in the dirt mix helps make things less muddy, primarily with the fat switch engaged.  That is the real magic of this pedal.




    Good stuff!

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