turning a DOD FX96 into a good analog echo
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ok, here's the deal. i have a DOD analog echo that i bought a few years ago for like $50US maybe.
didn't use it much though b/c the delay was so short. about 200ms. good for nothing but slapback.
did some research into it today and popped it open.
- it has a motorola MN3005 chip. now really hard to get. everyone sells it as NOS (new old stock) now. maxon used two in their hyper expensive AD900 to get 600ms. now they use four MN3008 chips (@ 150ms each) to get the same delay time. i believe the ones made by panasonic are the really sought after ones.
-the MN3005 is the chip used in the boss DM-2/3 and the ibanex AD-9. the boss's go for $200+US now and the AD-9 reissue is $300+
- the MN3005, like i said, can get 300-330ms although the datasheet for the chip listed the maximum at 250ms.
- the first generation of the FX96 had goofy tape echo graphics and a fixed 100K resistor across the delay time pot. this resistance determines the max. delay time.
- the later versions had a trim pot allowing easy adjustment of the max. delay time all the way up to 300ms.
so how to change the max delay time on the old FX96? increase the resistance across the delay pot to between 115K and 117K. any more than that and the delay won't work (i proved this by using 120K). i took 3 10K resistors and added them to the 100K like this.
100K+10K+(two 10K in parallel) = 115K
i now have a delay that compares very closely to the DM-3 and AD-9. at 1/4 of the price.
the FX96 is now discontinued. prices will probably go up.
i'll post pictures of the mod later.
edit: don't run 12V after the mod. it won't work. i tried it. either add the resistors or use 12V, but not both. 12V might blow up the pedal though. i don't know.
all of this i learned from harmony-central.com's effects database.
brilliant.
didn't use it much though b/c the delay was so short. about 200ms. good for nothing but slapback.
did some research into it today and popped it open.
- it has a motorola MN3005 chip. now really hard to get. everyone sells it as NOS (new old stock) now. maxon used two in their hyper expensive AD900 to get 600ms. now they use four MN3008 chips (@ 150ms each) to get the same delay time. i believe the ones made by panasonic are the really sought after ones.
-the MN3005 is the chip used in the boss DM-2/3 and the ibanex AD-9. the boss's go for $200+US now and the AD-9 reissue is $300+
- the MN3005, like i said, can get 300-330ms although the datasheet for the chip listed the maximum at 250ms.
- the first generation of the FX96 had goofy tape echo graphics and a fixed 100K resistor across the delay time pot. this resistance determines the max. delay time.
- the later versions had a trim pot allowing easy adjustment of the max. delay time all the way up to 300ms.
so how to change the max delay time on the old FX96? increase the resistance across the delay pot to between 115K and 117K. any more than that and the delay won't work (i proved this by using 120K). i took 3 10K resistors and added them to the 100K like this.
100K+10K+(two 10K in parallel) = 115K
i now have a delay that compares very closely to the DM-3 and AD-9. at 1/4 of the price.
the FX96 is now discontinued. prices will probably go up.
i'll post pictures of the mod later.
edit: don't run 12V after the mod. it won't work. i tried it. either add the resistors or use 12V, but not both. 12V might blow up the pedal though. i don't know.
all of this i learned from harmony-central.com's effects database.
brilliant.
Post edited by Unknown User on
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here's part of the board. the 3005 chip is near the centre.
http://www3.telus.net/alcoholiday/guitar/FX96mod/chip.JPG
here's the resistor across the time pot. why DOD would use 100K when it only took advantage of 2/3 of the potential of the chip's time i don't know. like i said before, they fixed that on the later versions.
http://www3.telus.net/alcoholiday/guitar/FX96mod/time%20pot.JPG
the new resistors that increase the total resistance and increase the delay time. it's ugly but it works.
http://www3.telus.net/alcoholiday/guitar/FX96mod/newres.JPG
and finally, since i was in there anyway, a new yellow LED.
http://www3.telus.net/alcoholiday/guitar/FX96mod/done.JPG
Hellllloooooooo
See ya