DOD - FX66 Flashback Fuzz [schematic]

[devastator]

Hi,

I've just received this pedal, and my god , that sounds so bad (the manuel deals with a "classick 70's tone" or "hippie fuzz" that's absolutelly not that.)

Very gainy, a lot of high frequencies, two tone control no really effective.

Here's the schematic :

DOD FX66 - Flashback Fuzz schematic

So, I think the key of the sound is the gyrators circuit that boost a particular frequency. How know the frequencies boosted ?

Do you see other things to do ?

thanks

(I'm gonna make another thread in modern stompboxes, I took several guts pics)

[devastator]

Any one has already worked on this pedal ?

[celadine]

Welll, its part of the DoD Grunge family (danelectro fab tone, dod death metal, some others), so some generic mods for those may help you. One interesting thing (which may be a schematic error) is no offset voltage for opamp U1B. So, how could a 95% Grunge clone imitate 60's fuzz!?! Only through the magic of marketing.

[devastator]

Actually I think you're right. There's some missing part on the PCB, you can see the marks (R18, C23 ect...) but not the components. So this Pcb must used for different pedal.

That pedal is really crappy, that sounds ugly. Imagine a big muff with only high frequencies, the "low" control has any effect on the sound.

I'll see the Grunge schematic to compare it with the Flashback fuzz.

I opened up it yesterday, the PCB must be really fragile, you can remove component once but not twice. So you've to find the good mod in the first time.

[devastator]

haha actually, no need to compare, I can read on PCB "FX69"

Dod guys were real genius !

[devastator]

So, no ones can say me how know the frequencies boost created by the two gyrator ? and how tweak it to remove this real harsh and high sound ?

[dan5150]

Can you post the gut shots?

[Sickle]

I have this one and the Grunge Box. They do not sound the same at all.

I can post guts of this one; I was about to auction it off, but I can tear it down before I do.

Its a pretty good sounding distortion, I prefer it to the Classic Fuzz, which I also thought was pretty good, too.

[dan5150]

That would be cool, thanks!

I used to have a grunge, and remember it being not bad at all. Maybe it's time to look for another one, cheap.

[devastator]

Guts :

I tried some little thing but nothing really change, that stay a bad distortion pedal. Actually the first gyrator (the one created by Q5) give a boost to 415Hz, then a gain stage ala RAT then another gyrator boost section that boosts at 5Khz. We add the two EQ band (bass/treble) and you got that pedal.

What I did :

remplaced R17 with a trimpot (20K) to calm down the gain, works goods but deosn't change the tone.
Disconnected the both gyrator , cutting the cap legs , you lose a lot of gain .
Rempleced the 47K linked the base of transistor (Q7/Q5) for a pot to make the frequency response variable, that doesn't work really well. I think the Q becomes bigger make the control useless

Anyway, modding that pedal wouldn't be worst than the regular sound, that's a really bad distortion box. I even don't understand how you can call that a "fuzz" , that's all expect a fuzz

(I gave up for this moment I've all project to finsih)

So if you got another ideas ....

[Sickle]

That would be cool, thanks!

I used to have a grunge, and remember it being not bad at all. Maybe it's time to look for another one, cheap.

I have one for sale if you want it! USA made, or at least the box it came in is..



Devastator, you're nuts, dude, I love how this pedal sounds! I'd say its more of a cross between a fuzz and a true distortion, sure, but not bad by any means. Then again, I have fuzz boxes I paid $2,500 for alongside others I got for $20, so my taste is pretty broad..

[devastator]

Just my tasted dude,

Actually, I really prefer the fuzz pedals I made or even my fulltone ultimate octave. not the same beast, but why "fuzz" there're nothing fuzz into it Just plug a real fuzz (fuzz face variant or anything you want) with the dod and you'd see what I mean. It's more , like you said, a distortion with particular frequency response. the gyrator make ALL the sound in that pedal (the gyrators seems to be used a lot in DOD pedal, every dirt box seem to have them) .

It's like a fixed wah (and I prefer the Q zone for that) (on down position) into a screaming rat with a tonestack to bring up more highs.

but yeah, I read some good review about it, I don't understand... Of course , that could be a cool dirt box for a particular spot in a song or to give a really nasty sound for a short moment but absolutely not a good main fuzz.

Anyway, that's not the subject of this thread

I take any ideas to keep modding mine. (I thought selling it but anyone wants it )

Electronic point of view, the PCB is really cheap and fragile, you've to work really safely.

Good Night guys...

[Sickle]

I just opened up both boxes and had a look, and yep, same pcb in both, but different components all over, different opamp/IC's and caps, etc.

I did a side by side with the two again to make sure I wasn't crazy, and I have to say again, they still sound very different. The root distortion type is still there, btu they are voiced *very* differently.

At the following settings, I get these results:

Volume at noon, bass, treble, and fuzz at max

Grunge box: HEAVY scooped mids, and more amplitude. Thicker, more rounded out bottom end.

Flashback Fuzz: Less amplitude, flatter EQ response, and somehow, slightly brittle sounding, even through a baritone, but run the volume at max and it gets much thicker pretty quick.

If I could have the higher gain and output of the Grunge with less of the scooped mids, more voiced like the Flashback, but with the Grunge's balls, that would be a really good circuit, maybe even a rival to the Rat2.

Here's a shot of both side by side:

And for contrast, here's the Classic Fuzz, which seems much more reasonable a circuit..I've had a burning question forever now: What the HELL did DOD need to make these circuits so fucking complicated for?!?!

And just for shits and giggles since I'm taking shots of the cheap-0's, here's the BOSS Hyper Fuzz:

[devastator]

The boss FZ2 (superfuzz clone) looks more interesting than the flashback fuzz.

Actually it's not similar to the Grunge but it is based on the same design. Gyrator "pre" and "post" distortion with two cut/boosts pots for treble and bass. I never played with a Grunge but in looking the schematic and after I head the FX66 I really don't want.

Anyway, any suggestion to make it better ?

[Greenmachine]

Hey Sickle, (or anyone)

Know how to make that Classic Fuzz sound any different/better? I've got one and it sounds like the Big Muff's poor cousin.

Thanks

[devastator]

actually I found out (with help from another forum) how break that ugly fixed-wah sound, espcially for a big muff type of sound.

remove the 47K resitor linked to the base of the transistor who makes the gyrator and disconect the second gyrator (after the distortion AOP) to remove it completely of the structure.

With these mods that sounds really fuzzer , you have a decent fat fuzz pedal with a really usefull tone control.

I've sent the pedal this pedal this morning (someone bought it) so i couldn't help more.

night.

[edge59]

Does anyone have a schematic for the Flashback Fuzz? I cannot find one.

Thanks
Ed

[astrobass]

If you email DOD and ask they'll usually give a schematic. The web form to request support asks for a serial number, so ideally have one, but I'm sure if you ask nicely they'll help out.

[Nocentelli]

Does anyone have a schematic for the Flashback Fuzz? I cannot find one.

Thanks
Ed

This one?

http://experimentalistsanonymous.com/di ... 20Fuzz.gif

[pervyinthepark]

I have one of these. They are total garbage. I modded mine by stringing some pieces of wire around. Mess around like that and you'll find some way fuzzier sounds.