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Krankosaurus: 'Presence' Mod

Started by nzCdog, December 15, 2010, 08:50:38 AM

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nzCdog

Pinched this idea from freestomboxes.org and its really working for me.  I built the Krankosaurus version 3 and did pauloman's 22n input cap mod which took a lot of the extra bass out. 
The presence mod is simple: Replace R16 with a pot (I used 50k trimpot, some recommend 25k)  In practice the pot works nicely with the tone control to shape the treble detail of the pedal.  I have the trimpot inside mounted on the PCB and have it set to about 17k Ohms...

The result for me is now I set the tone control to 12 O'clock and the Krankosaurus has nicer treble detail, a better match to the bypassed 'clean' sound of my amp.  Basically = Happy Cdog! ;D YMMV
Btw, love to hear from an expert why this works

pauloman80

Quote from: nzCdog on December 15, 2010, 08:50:38 AM
Pinched this idea from freestomboxes.org and its really working for me.  I built the Krankosaurus version 3 and did pauloman's 22n input cap mod which took a lot of the extra bass out. 
The presence mod is simple: Replace R16 with a pot (I used 50k trimpot, some recommend 25k)  In practice the pot works nicely with the tone control to shape the treble detail of the pedal.  I have the trimpot inside mounted on the PCB and have it set to about 17k Ohms...

The result for me is now I set the tone control to 12 O'clock and the Krankosaurus has nicer treble detail, a better match to the bypassed 'clean' sound of my amp.  Basically = Happy Cdog! ;D YMMV
Btw, love to hear from an expert why this works

Thanks for the mod props, man!  I'm very intrigued by the presence mod you found, might need to try that on another build.  No idea why it works, curious about it myself.
--------------------------------------------------
Regards,
pauloman80

nzCdog

word pman ;) the 22n sounds much better

stecykmi

good idea! the explanation is simple, R16 and C8 form a low pass filter. By changing the value of R16, you change the notch frequency of the filter. stock, it's probably something like 4k. with the mod, it'll probably range from something like 1k to about 8k. these are just guesses with no math or anything.

this mod would also work with R17.

nzCdog

ah cool ty ;D
i should get around to recording an mp3 of it in action
this pedal is still naked tho, working on the paintjob... slowly

nzCdog

Further to this mod thread... I actually ended up changing things again since my last post... input cap back to 100n, presence trimpot removed and R16 changed to 18k... and 2 clipping LEDs added after C5
Sorry to dredge, this is just to set the record is straight as I got some Q's about my former posts

Quick demo of the finished product


bigmufffuzzwizz

Great demo of a great pedal! the boost is very transparent sounding.
Owner and operator of Magic Pedals

gtr2

Quote from: bigmufffuzzwizz on April 30, 2011, 06:17:41 AM
Great demo of a great pedal! the boost is very transparent sounding.

+1 thanks
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