DOD EchoFX (FX96)

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DOD EchoFX (FX96)

Postby KHELSTROM » 21 Oct 2008, 14:41

Just picked this one up for only $25 and it uses a MN3005 analog delay chip. One weird thing tho is that it has a maximum delay time of only about 200ms. What's the best way to go about extending the delay time to a full 300ms?

Schematic: http://schematicheaven.com/effects/dodfx96_echo.pdf

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Re: DOD EchoFX (FX96)

Postby Cow4prez » 22 Oct 2008, 22:20

there exist several trimmers on the inside. One of them will allow you to tweak the delay time slightly.
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Re: DOD EchoFX (FX96)

Postby uncleboko » 23 Oct 2008, 10:36

Trimmer capacitor for C19
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Re: DOD EchoFX (FX96)

Postby KHELSTROM » 23 Oct 2008, 13:39

There are actually no trimmer pots in this circuit though. :scratch: but I'm sure I could add one. From what I can tell so far the schematic I posted a link to is very accurate.
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Re: DOD EchoFX (FX96)

Postby Dirk_Hendrik » 23 Oct 2008, 17:00

Whatever trimmer or not, uncleboco is right. Start increasing the value of C19
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Re: DOD EchoFX (FX96)

Postby KHELSTROM » 23 Oct 2008, 21:23

Thanks guys. I'll try this.
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Re: DOD EchoFX (FX96)

Postby KHELSTROM » 24 Oct 2008, 17:05

I should have just looked at the MN3001 data sheet :oops:
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Re: DOD EchoFX (FX96)

Postby oculus » 05 Nov 2008, 04:06

hi im kind of a newbie to modding pedals..i have a dod fx96 with just 200ms with no trimmer,
i would like to make the delay time longer.do i then just take capacitor 19 out and put a bigger one. the bigger the longer the delay?
what capacitor size would you recomend. i don´t mind that it gets really lofi on longer delay time
but would it sound worse at a short delay time with a bigger capacitor installed?

also i would like to be able to make it self oscilate. would that be just another capacitor that i have to change for the feedback?



thanks greetings Fridfinnur
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Re: DOD EchoFX (FX96)

Postby KHELSTROM » 05 Nov 2008, 18:32

oculus wrote:hi im kind of a newbie to modding pedals..i have a dod fx96 with just 200ms with no trimmer,
i would like to make the delay time longer.do i then just take capacitor 19 out and put a bigger one. the bigger the longer the delay?
what capacitor size would you recomend. i don´t mind that it gets really lofi on longer delay time
but would it sound worse at a short delay time with a bigger capacitor installed?

also i would like to be able to make it self oscilate. would that be just another capacitor that i have to change for the feedback?



thanks greetings Fridfinnur


I threw a 100pf in mine because that's all I had at the moment and it is definitely too big. It did increase delay time but definitely beyond the limits of the IC. Somewhere between 25 - 100 pf should be good but I haven't had a chance to get down to my parts supplier yet and experiment more since I've got a reissue super lead plexi on the bench at the moment. :D Fun times!
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Re: DOD EchoFX (FX96)

Postby analogguru » 05 Nov 2008, 21:32

put 2 100p in series in the meantime.

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Re: DOD EchoFX (FX96)

Postby oculus » 07 Nov 2008, 00:53

thanks.i´ll try that.
what about the feedback do you guys know how to make it longer so so the pedal can selfoscilate
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Re: DOD EchoFX (FX96)

Postby jrjoe21 » 30 Nov 2009, 01:22

Have you tried running it with a 12v power supply instead of 9v... Makes a huge improvement with this pedal... It becomes a lot clearer, the feedback can be set higher without getting muddy... and the tape quality knob actually becomes useful. Don't know how safe it is, haven't analyzed the schem and parts voltage ratings yet. But I assume its safe as some delays using MN3005 (AD900) run at 12v + its a small difference.

p.s. I have the old model without internal trimpot and with the reel graphic, dont know if the later model behaves the same.
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Re: DOD EchoFX (FX96)

Postby l2yz » 05 Sep 2010, 15:23

has anyone tried running this at 18v? checked the parts list and several capacitors are rated for 16V... would changing them to a higher voltage and then running at 18v be safe? reason is i'm trying to use an 18v slot on my dc brick
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