DOD 440 Clone

[Lp_man]

Hey guys, I recently bought a DOD 440 circuit board (GGG) and componetnts and I'm having a really odd problem.

The effect comes through but only slightly and its hardly noticable. I checked my resistor values and cap values, orientation of the caps and diodes (one diode was backwards but I put it right). Any ideas of what it could possibly be?

Thanks in advance!

-Will

[Lp_man]

The formalities:
1.Name of the project: DOD 440 EF, from General Guitar Gadgets.
2.Links to the source of the project: http://www.generalguitargadgets.com/index.php?option=content&task=view&id=138&Itemid=153
3.Mods: a spdt switch that selects a 1Uf or 10uf capacitor for the 'linger' mod. Swapped R5 to a 1m resistor as suggested
4.Any parts substitutions or modifications you made to the original? Nope.
5.Whether or not it's a positive ground circuit? I think it is a negative ground.
6.What it does and does not do; very small ef sound comes out when plugged in, bypass fine have to turn both knobs all the way up to get a very small ef filter sound from it.

I don't know how to measure IC voltages (I do have a DMM so if I am instructed I'll be able to do it)

[didier]

you should know the 440 is a pedal that needs alot of playing around with to get a nice effect that will please you...

i'm building one right now and i must say, i'm doing it for the quite subtle effect it van give you.

guitargeek says:
"DOD 440 Envelope Filter - If you?re expecting an overdose of funk from this fresh green fellow, you may want to look into the newer DOD FX25b or the Electro-Harmonix Q-Tron. The 440 is less pronounced than most of the filters out there and that subtlety is what makes it so sought after. Despite the relative shyness of the wah sound, it?s ultra-thick and fills up a lot of sonic space. Since it?s a touch sensitive effect, a great deal of the overall success of the effect depends on you. ..."

and continue reading the reviews on harmonycentral:
http://reviews.harmony-central.com/reviews/Effects/product/DOD/440%20Envelope%20Filter/10/1

every last one of the reviewers says it needs some time before you find the right settings.

did you already try it after a booster/overdrive? give it a try...

if it still surprises you that this effect is so "weak", learn how to handle a digital multimeter and give us some voltages

[Lp_man]

I'll try putting the booster I built before it tomorrow, I was expecting something more along the lines of Tone Factors 440 clone.

-Will

[didier]

since tone factor seems to be down i can't tell you anything about that...

*edit
It's back up so i had a look.

what reminded me, do you know that the "level" or "sensitivity" knob sets point at which the effect starts kicking in...

try yours with sens at 0 or just a little open and range halfways and if you dont notice the effect there there s something wrong...

[3/4 North]

Is R6 suppose to be 2.2k and not 22k?

[didier]

Is R6 suppose to be 2.2k and not 22k?

where did you see that?

[3/4 North]

I'm in the process of building the byoc DOD 440 now and I always check these against the ggg schems. The byoc board has the resistor marked 22k but the instructions point out that this is incorrect and that it should be 2.2k

[Lp_man]

Ahh that could explain it, I'll mail GGG again, I got a response saying that I needed to check R1/R2. I managed to get the effect working, it was weird, the LED burnt out and the circut started working slightly but I got some real starwars lazer noises...

...it was actually quite cool...

-Will

[Dan N]

R6 was 6K8 in the red model we looked at here. It may have been something else in the green model the Tonefactor is based on. 2K2? Would not surprise me. I think the green also used something like a 4558 instead of the TL022.

If you like weird noises, the resonance pot mod Mark Hammer posted is pretty fun. Replace R12 with a 100K pot in series with enough resistance to get  a usable range (in mine 410K). Ugly sellf oscillation when turned all the way up!

[Lp_man]

Replasced with a 2k2 and it works great! Thanks guys!

[Lp_man]

Even though you all probably know what these sound like ... im in the mood for a celebratory clip!

http://www.soundclick.com/bands/songInfo.cfm?bandID=452640&songID=4405146

[3/4 North]

That sounds great!
I need to get mine finished

[didier]

me too

only problem still is the VTL5C4/2

i can get it at banzaieffects but i first want to try some not-so-local shops

[didier]

damn i want to play audioslave - be yourself with this thing

[Lp_man]

me too

only problem still is the VTL5C4/2

i can get it at banzaieffects but i first want to try some not-so-local shops

I got mine from small bear

damn i want to play audioslave - be yourself with this thing

I think he just uses a regular wah for that, or thats how I used to play it!

[jsleep]

I just checked this out myself and the 2k2 does sound considerably better.  Mine actually worked with a 22k in there, but with a bassier sounding quack.   I tried some different values with a resistor breakout box and I thought 2k2 sounds better than 6k8 with the 1M in R5, but with R5 as 470k, probably 6k8 was better.   With R5 as 1M and R6 as 2k2, it seems to sound really the best to my ears and Will's sound sample sort of proves the point.  Thanks Will.

I will update the project to use these values with notes about the probable original values.

JD Sleep
General Guitar Gadgets

[3/4 North]

amazing, so much love for byoc...

is there a feud or something going on?
We just want to build pedals.

[Lp_man]

amazing, so much love for byoc...

is there a feud or something going on?
We just want to build pedals.

What are you on about?

[Mark Hammer]

I just checked this out myself and the 2k2 does sound considerably better.  Mine actually worked with a 22k in there, but with a bassier sounding quack.   I tried some different values with a resistor breakout box and I thought 2k2 sounds better than 6k8 with the 1M in R5, but with R5 as 470k, probably 6k8 was better.   With R5 as 1M and R6 as 2k2, it seems to sound really the best to my ears and Will's sound sample sort of proves the point.  Thanks Will.

I will update the project to use these values with notes about the probable original values.

JD Sleep
General Guitar Gadgets

Two things:

1) IC1a needs to provide enough gain that, once rectified, there is sufficient envelope voltage to produce a sweep out of anything you feed it.  With R5=1M, you range of gain is approx. 11x to 100x.  If that's still not enough, dropping R4 down to 6k8 oughta do ya.

2) That Vactrol is half LED.  So, if you were feeding an LED with +9v, what value current limiting resistor would YOU put in series to provide just enough light?  What the Vactrol is seeing from the D2/C4 junction is considerably less than +9vdc.  So, even if you don't need *full* illumination of the LED encased on epoxy to get the requisite quack, the current limiting resistor (R6) still needs to be within reason to get at least a little light shining on the LDRs.  A 2K2 value permits more current to be delivered to the LED.

Given that there is a small resistance in series with the LED, this opens up some interesting possibilities.  Normally, a small value resistor (between 47 and 330R) is found between the functional equivalent of D2 and C4 to add some lag and slow down the attack time.  You can crate a variable attack by inserting a small-value pot (500R or 1k) in that spot.  Unfortunately, since it also limits current, any increase in that resistance value will not only produce a slowed attack, but will also reduce the "drive" of the LED so that you get less sweep as you turn up the attack pot, necessitating an adjustment of the sensitivity control.

With the 440, however, it is possible to easily keep that current drive constant, while varying the attack time.  Here's how.

If R6 at 2K2 works for you, then replace it with a 1k pot in series with a 1k2 fixed resistor.  Treating the two outside lugs of the pot as if they were a fixed resistor, you have a series resistance of 2k2.  Now, tie the wiper of that pot to the 1uf (or whatever value you pick) cap to ground.  As you move the wiper around, the current-limiting resistance will NOT change (unlike the typical variable R/attack mod  I frequently suggest), so the sensitivity will not need adjustment.  However...because the leg of the pot between D2 and the wiper can vary from 0R to 1k, you can have a broad range of charge-up times for that cap, and a "penalty-free" attack control.

Just note that if you like the idea of two cap values to introduce lag and extended decay, the attack time is a function of both the resistance of that leg of the pot AND the capacitance value, so switching caps will alter both attack and decay.

I'd never heard one before the posted clip.  That's a nice-sounding unit.