DOD - FX25 Envelope Filter  [schematic]

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paperhouse
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Post by paperhouse »

I was given a non-working FX25 today. Most of the wires are disconnected inside and their jacks and power supply are strange. If someone has one of these pedals and they wouldn't mind taking a few pictures of the insides I'd greatly appreciate it.

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Post by soulsonic »

Which one is that? I have a handful of older DOD pedals.

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Post by trevize »

this one? :D

I heard amazing samples of this auto wah, very "synthy".

http://topopiccione.atspace.com/PJ11DODfx25.html

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Post by chris_d »

I have one of these that i need to fix the switch on. Makes some pretty wild noises. Haven't found a practical purpose for any of them yet though! :D

I should probably just play more funk bass.

-chris

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soulsonic
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Post by soulsonic »

I never had that one.... never thought to get into the whole auto-wah thing.

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Post by chris_d »

soulsonic wrote:I never had that one.... never thought to get into the whole auto-wah thing.
I am not sure that i would ever buy one on purpose, but my policy of accepting just about any broken piece of electronics here means i occasionally wind up with something like it!

-chris

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Post by paperhouse »

someone gave it to me for free so i figured it would be fun to play with.

it looks like this on the outside:

Image

and it's a rev G board:

Image

and it has some names inside:

Image

this is way messed up inside. and apparently it didn't work before all of the leads inside were mixed up. i think the only way i'll end up fixing this is if i buy another one and break out the DMM.

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Post by trevize »

there's the schematic on the link I posted.

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Post by Eloy »

Any idea how to add a blend control like the FX25B ?

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Post by krome_magnon »

Here are the schems for the 25 and 25B.

ImageImage

I used to have a 25B and the blend control is very useful. Especially when using the box with a bass. had to sell it when I was short of money, but I might have a swing at building my own.
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99837_DOD_FX25_B_122_896lo.jpg
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Post by bajaman »

Hi Krome
Thanks for the schems :D
bajaman

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Post by Gila_Crisis »

i'm going to build an FX25 following topopiccione.com project. but i was wondering if it could be possible to add an UP/Down switch to change the direction of the envellope.

do you have any ideas???
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Post by borislavgajic »

some pictures of PCB ? :?

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Post by borislavgajic »

THANKS !!!
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Post by phuzle »

Apparently the switching system on these is bad. A friend of mine, a touring guitarist, has gone through about 10 of them that have all broken or just become inconsistent in the switching. I told him I could try to fix them for him so he wouldn't have to buy more, and we were thinking that true bypass might be the way to go about it. Only thing is I'm not quite sure how to convert the circuit to be always on, so that I can use a 3pdt to do the switching. Anybody have some advice?

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Post by piod »

schemes not work, some mistakes in it

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Post by Ice-9 »

phuzle wrote:Apparently the switching system on these is bad. A friend of mine, a touring guitarist, has gone through about 10 of them that have all broken or just become inconsistent in the switching. I told him I could try to fix them for him so he wouldn't have to buy more, and we were thinking that true bypass might be the way to go about it. Only thing is I'm not quite sure how to convert the circuit to be always on, so that I can use a 3pdt to do the switching. Anybody have some advice?
Looking at the schematic in the above post. You will need to remove the two FET's (for some reason there both labelled Q2) The top fet will need a link between the D and S, this should now put the effect perm on. The 3pdt swich can now be wired in as you would for any true bypass effect, ie at the input and output and the last pole for LED.


I just noticed this request was a year old. Oh well nevermind.
It's fairly straight forward, if you want to start it , press start. You can work out the rest of the controls for yourself !

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Post by Hoony »

Hey there,
I have taken to removing the guts from my pedals and wiring them into a rack and leaving the switches on the floor. Yesterday and today I'm trying to get the DOD FX25 to work. I got really tired this morning and forgot where things were wired to the board. Any body got a block diagram of the circuit I can't tell where the leads go by the schematics...
If someone has one of these they could just describe where the ground is, the input etc.
Please help a dummy out.

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Post by Brian M »

Hey, it's not the one posted in this thread, but there is an even older FX25 that uses CD40XX chips. Similar to the original MXR filter and (if i remember correctly) the blue version of the 440.

I have one. It is most certainly the worst filter DOD ever made.

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