## DOD - FX22 Vibro Thang[schematic]

All about modern commercial stompbox circuits from Electro Harmonix over MXR, Boss and Ibanez into the nineties.

### Re: DOD - FX22 Vibro Thang

normal elco actually conduct in the reverse direction, two 1uF polarized act like they each have a diode in parallel with them that conducts when the voltage is backwards for that one cap.

Yes, that explains why two polar caps can be attached in series to create a non-polar cap. But that doesn't explain how the math for adding caps in series has somehow changed. Why would it be different for 1u caps than for any other value?
induction
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### Re: DOD - FX22 Vibro Thang

induction wrote:But that doesn't explain how the math for adding caps in series has somehow changed.

-----l C1 l------l C2 l-----

Ctotal = (C1xC2)/(C1+C2)
C1 = C2 so we can rearrange this to
Ctotal = (C1 x C1)/(2 x C1)
Which simplifies to
Ctotal = C1 / 2

So 2 equal value caps in series gives you a cap half the value of one of them (unlike 2 resistors in series where you add the values). It is capacitors in parallel where you add the values to determine the resultant value.
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deltafred
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### Re: DOD - FX22 Vibro Thang GUTS - no schema yet

mictester wrote:
trubac wrote:Thanks fior answering !
No my modified one works perfectly independantly of the mod.
The problem is the new one on wich the speed doesn't go as fast as on my first one.
By reading the diagram kindly post by DoctorSound I can 't really see what could be the culprit ...
RPMS controls the speed .... DROP the depth.
[ Image ]

What nonsense from DOD!! It's the tolerance of C25 - most electrolytic capacitors have a wide tolerance - often as much as 20%! Your 4µ7 could be as low as 3µ7 or as high as 5µ6. If it's higher in value, the oscillator will run more slowly....

Thanks! 2.2 was the perfect value! Slow to hummingbird!
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### Re: DOD - FX22 Vibro Thang

Can't believe that there's no layout yet.
This pedal is so underrated.
Madbean, Sabrotone, Tagboardeffects, where are you?
roseblood11
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### Re: DOD - FX22 Vibro Thang

I've done one last year.
It's on the main page:
http://tagboardeffects.blogspot.fr/2016 ... mment-form
albru80

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### Re: DOD - FX22 Vibro Thang

Great! Why didn't I see that?

Are schematic and layout really verified?
Has anybody compared his built with the original pedal?

It looks a bit strange that R44 and R45 (4k7 and 7k5) are in series..
roseblood11
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### Re: DOD - FX22 Vibro Thang

roseblood11 wrote:
It looks a bit strange that R44 and R45 (4k7 and 7k5) are in series..

maybe thei were tinkering after production until they got the max depth right? a trimmer would have been better

anyways, not a very good effect, the idea is good (the VCA/VCF thing), but the sound is kind of muddy, there are way better phasers
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