Dod FX66 Flashback Fuzz - Modding

Started by MASTER VOLUME, March 31, 2007, 10:44:30 AM

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MASTER VOLUME

Hi there, just got myself one of these pedals very cheap (£17)from Thomann. While it's a good pedal it doesn't have enough bottom end ,it's very trebley and the fuzz isn't crunchy enough.
At it's max fuzz setting it sounds like the heavy guitar on Radioheads creep. I wanna mod it to make it more to smashing pumkins siamese dream sound.
Here's the schematic www.schematicheaven.com/effects/dodfx66_flashback_fuzz.pdf
I was thinking of increasing the input cap C2 to 0.1 UF to let more bass in and changing one or both of the clipping diodes to germanium as they are silicon.
All suggestions welcome and has anyone tried other mods with this pedal ?
Thanks.

MASTER VOLUME


bluesdevil

For more bass, I would try raising the input cap as well. Germanium diodes would clip more and give more saturated fuzz because they clip sooner, but not exactly more crunch, I think. I've heard of folks here using red LED's in other circuits for more "crunch" (less clipping).
          Would be good if you could socket those components and swap out for comparison to find your favorite values or diode combo's if possible.
"I like the box caps because when I'm done populating the board it looks like a little city....and I'm the Mayor!" - armdnrdy

tiges_ tendres

Quote from: MASTER VOLUME on March 31, 2007, 06:20:18 PM
Any one got any suggestions? ;)

Yes. If you want to sound like smashing pumpkins, buy a big muff.
Try a little tenderness.

MASTER VOLUME

QuoteYes. If you want to sound like smashing pumpkins, buy a big muff.
Where's the fun in that? :icon_biggrin:

Meanderthal

 On the other hand, since ya want a BMP like sound and the BMP has dual clipping stages, why not add a second clipping stage, perhaps in the feedback loop of an opamp gain stage? Could be switchable, may require gain tweaking... but replacing 2 Si diodes with 4 Ge diodes should 'even' out the gain loss(I think).
I am not responsible for your imagination.

MASTER VOLUME

Well, i've changed the input cap from 47nf to 220nf and one of the clipping diodes to a germanium diode.
It now sounds fatter than before an the fuzz is more pronouced,more ragged.
The tone control is can now get above 3  :D

Processaurus

Does anyone know what the 2n5088 transistors are doing connecting the inverting inputs to ground on both U1B and U4B?  Haven't seen that before, I'm kinda curious.

I came into one of these recently, I would like to make it do something novel, since a man can only have so many fuzzes in his life.  Maybe substitute something fun into the beginning and just use the existing EQ and output section, + the bypass switching?  An octavia might be fun...

FUZZFACEMAN

sorry for reviving a super old thread.  anyone who is familiar with basic circuits/reading a schematic can help me with this.   ;)

i'm a beginner at reading schematics, etc. and could really use help from anyone that can understand basic circuits.  you said, above, that you changed the 47nf to 220nf on the input cap, which from following the schematic seems to be C4, correct?  you also said you changed one of the clipping diodes to a germanium (giving the pedal a more tubey and less sharp clipping sound... which is exactly want i want to achieve).  i just don't know which diode is at the clipping stage.  i'm guessing it is either D2 or D3 -- are you saying you can change either of those to a germanium?  or are you talking about D1... on the schematic, D1 seems to be right before the fuzz stage and D2 and D3 right after the fuzz stage.  Which are the clipping diodes then?  Guessing D2 and D3, but just want to make sure before I go operating on a delicate PCB!  would there be a difference in sound depending on which of the diodes (d2 or d3 are changed as they are right next to each other?)  guessing it would!  any help on this would be great.  figured it'd be cool to revive an old thread as this is the only one on this pedal mod that seems most straight forward.  adding low end and more classic fuzz tone to this pedal.  THANKS A BUNCH in advance for your time  :)

LINK TO THE SCHEMATIC:
http://www.schematicx.com/schematic/dod-fx66-flashback-fuzz-fx-pedal-schematic/

blueedge59

The link to the Flash Back Fuzz are down, does anyone have a copy I can get please?

Thank you kindly!

Ed :)