Ego Driver

[mjcyates]

Just completed an Ego Driver build yesterday. Good news, it worked right out of the box, no issues. Love it when that happens. Not so good news, it doesn't sound very good. One setting of the HP/LP switch sounds thin and trebly, the other sounds wooly and bassy like it has a blanket over it. I built it straight from the project file with no substitutions. Any thoughts for improving the tone? Any help or insight is appreciated.

[madbean]

Hmm, well having built this one a couple of times, and having owned ver.2 I can say that overall, the circuit is a little more bassy and dark than other OD's. With v4 of the OCD, C3 (my schem) was changed from 100n to 68n to help lighten it up a bit. I have not tried this particular change.

Anyway, the HP/LP filter (normally) will alter the tone some, but it also should have a pretty big volume jump. Given the big difference you are noticing, you could make some alterations to suit your taste. I'm assuming that you have have double checked that you have used the correct values for the caps and resistors. You can try lowering the value of C8 to 22n. This will alter the frequency range of the tone knob some (less dark) and also decrease the amount of low pass filtering generated by the R10/R11 and C8 combination. You could also try increasing C3 back too 100n to somewhat balance out the previous changes. At 68n, the feedback loop is applying gain in the 1k+ Hz range, whereas at 100n it brings it down to around 720Hz, which is more midrangey.

Try these out and see what you like. Also, if you are not using the TL082, try getting one at Radio Shack. A TL082 is a noisier version of the TL072. Fuller's choice of this particular op-amp is curious, and from what I've read some suspect that noise actually get perceived as more harmonic content in a weird pyscho-acoustic way.

Let us know what you find!

[mjcyates]

The board version I have is 2.5. I double checked all components and they match up with the project 2.5 document. C3 is currently 100n. I noticed that the new version does not have C11. Version 2.5 has C11 as 100n. Also found a fulltone document that said the output cap was changed from 10uf to 1uf tantalum. Don't know what difference that would make. The switch option that is brighter does have more volume than the darker option. I originally put a TL082 from Radio Shack for the IC. I replaced it with OPA2604 which is a little better.

[madbean]

C11 isn't necessary. It's something I added in as additional filtering for PS. But, it was really overkill, so I decided to remove it. You will sometimes see parallel caps for filtering, usually a large electrolytic and a small film or ceramic. The idea is that mixing the two values and types can better filter DC ripple from an unregulated power supply. But, since almost everyone uses regulated power supplies now (or battery) it isn't a big deal. It certainly doesn't hurt, but you won't miss it.

The change from 10uF to 1uF tantalum could influence the tone a little. Not so much from the value, but there probably is a nominal difference in sound between electrolytic and tantalum. Personally, I never use tantalum because they are less stable and tend to fail more frequently than the other. But, some people do like the "sound" of them. If you want to switch C7 out for the 1uF, then go for it! Just be sure you orient it the right way because they will fail if put in backwards.

You could try a few other opamps if you have them handy. My favorites are LF353N, NE5532 and TLC2272. And with the other mods I suggested you might find something you like. Or, it may just not be for you. I sold my ver.2 OCD because I thought it was a little dark for my tastes, but I found that I missed it after a while so I built one. I actually used it quite a bit on some sessions for my band. When I listened back to it later, I was like "yeah...that was just the right effect for that part". Also, I don't know what you are playing through, but Fuller does tend to voice his stuff for Marshall amps. Originally I was playing one through a Vibrolux, and never really bonded with it. But, once I plugged it through my friend's 18W Cage amp, it really came alive.

[mjcyates]

Thanks for all the info Brian. For reference my stock tone is Reverend Warhawk into Barber Tone Press, into Barber Direct Drive into Barber EQ into Nova Repeater into clean channel of Fender HRDX with Texas Heat speaker. I will probably tweak the pedal some, but as you said, it may just not be for me.

[guitarnerd24]

what if i want a dc input and not use a battery i cant tell if the build has that option? and which version corrisponds to which actual ocd pedal?

[madbean]

what if i want a dc input and not use a battery i cant tell if the build has that option? and which version corrisponds to which actual ocd pedal?

You can still follow the wiring diagram as is. Just leave off the battery clip hookup. I pretty much never put batteries in my stuff, either.

The newest version of the EgoDriver corresponds to ver.4. The previous versions correspond to version 3. The difference between the the two is a change in value for C3.

[slash555]

i built ego driver few times and it's always dark and bassy. i adjusted mine something like you sugested and it's fine now but theres one other thing that's bothering me. no matter what i changed when some other pedal is engaged after egodriver in singal chain i get vol boost and alot of high boost (delay, od, dist, tremolo..). i built several different pcbs and always got the same resoult

[kokohi5]

I just finished building this last night. At first, the light would come on but I wouldn't get any sound and the opamp got a little warm after a while. I checked for possible traces on the board and took care of some places that looked like they could be the problem. It works now, but it just sounds like a really mellow fuzz. Any ideas?

[kokohi5]

By the way, I measured my voltages on the opamp and I have full on 8, nothing on 4 and half on the rest. Is this correct?

[madbean]

Hmm, a mellow fuzz sound. Definitely not right. Looks like your voltages are okay on the IC. You should have 9 on pi8, 0v on pin4 and around 4.5v on the rest, which is what you are describing.

Even if the 2n7000's were installed incorrectly you would still get quite of bit of clipping from the op-amp. So, I don't think that is your issue.

Did you do any subs for any of the values? Have you tried any other IC's in place of the TL082 to see if you have a bad part?

[kokohi5]

I tried two different opamps and a different set of 2n7000's and get the same results. I socketed C7 since I've built the circuit before with a 1uF cap, but I get pretty much the same results with either 1 uF or 10uF. I also swapped D2 with a different diode thinking that might have something to do with it, but it still sounds like a big ol' blanket over the amp. All of the other values are the same as on the layout and schematic.
I'll play around with it later and see if I can find any traces on the board or if I've got something wired wrong with the jacks and switches.

[okgb]

Hopefully a simple mistake BUT
my E.D.  just seems to have a small farty peak leakage
well The signal doesn't seem to make it through the
fisrt opamp section [ from a scope ]
i didn't have the tlo82 but tried a couple of the
suggested 5532 as a sub .
at pin 3 the waveform is already half [ and starting to look mishapen ]
of the before the input cap .
I'll check the voltages mentioned in above post , but it was getting
8 something on the 9v in
tia for any suggestions [ i don't mind stupid easy fixes , ha ! ]

[okgb]

O.k. i really need glasses [ that and it's hard to tell brn from org from rd
on those blue 2 % resister ]
using a magnifying glass i found a small solder bridge to ground
it's working now , It is a little fuzzier [ and softer] than i'm used to

First observations , the hp switches adds quite a boost ,
max level of overdrive is less than a rat , normal ?
coming from a t.s. background this will be a nice color

[okgb]

Yeah  , I'm finding mine a little too  " woofy "
I don't feel it lacks brightness but that there is too
much " loose " low end
Quick fixes ?