Anyone know how to make the dod 440 e.f. more lush?

[Devius]

I figured out the problem, after of course questioning my sanity, I had with the ggg dod 440. Works awesome, I'm going to do the adjustable Q mod.
However, I would like to make the effect a bit more pronounced. When I add fuzz or my amps distortion, it's not quite as noticeable.
Anyone know how to tackle this?

[Devius]

And where could you splice in an lfo?

[John Lyons]

Depends on the order of the pedals. Try before and after.
I kind of like it before myself. Q mod will help as well.

[Mark Hammer]

All filters sound more obvious when there is more spectral content to filter out.  So, a 440 will sound "better" with a distortion in front of it.  Unfortunately, the distortion will reduce the dynamics of the signal so that you'll get less sweep, or at least a different feel to the sweep.

[Mike Burgundy]

...Which can be remedied by intorducing an effectsloop to the pedal. The envelope detection listens to the straight signal, after that the loop signal gets filtered. Like a Meatball. Unfortunately, this is a bit tricky in a pedal this simple. IIRC both envelope detector and filter amp are unbuffered, so you may run into trouble. What could prolly work is having the detection circuit the same, but insert a buffer (and the loop just after that buffer) before the filter circuitry.

[Devius]

Would it be worth modifying this circuit or start from scratch with another?

[Mark Hammer]

...Which can be remedied by intorducing an effectsloop to the pedal. The envelope detection listens to the straight signal, after that the loop signal gets filtered. Like a Meatball. Unfortunately, this is a bit tricky in a pedal this simple. IIRC both envelope detector and filter amp are unbuffered, so you may run into trouble. What could prolly work is having the detection circuit the same, but insert a buffer (and the loop just after that buffer) before the filter circuitry.

Exactly what I was thinking (but didn't have the time to write).

Take a look at the schematic for the 440: http://www.generalguitargadgets.com/diagrams/ef440_sc.gif

Now look at the schematic for the Dr. Q: http://www.muzique.com/schem/doctor-q.gif

Both have two op-amp stages: an envelope follower and a filter controlled by the envelope.  In the Dr. Q, those two paths part ways right at the input.  In the 440, they share a common path, via C1 and R1, and then split off in different directions.  What that says is that the envelope follower, built around IC1a, needs that 10k input resistance, and a DC-blocking cap, provided by C1.  Let's say that we leave those in place, cut the path from IC1a pin 3 to the junction of R1/R2, and provide a separate parallel path to the input by adding another 10k resistor and .01uf cap, such that, from the input, the signal immediately splits off in two directions.

So, what does this buy us?  It allows us to have an additional jack for a "sidechain input".  Using a mono closed-circuit jack, with nothing plugged into it, this parallel path is automatically connected to the circuit input.  But, plug something into that jack, and now the envelope is detected for whatever you plug into the jack.  It still controls the filter in the same manner, but that envelope input could be whatever you want.  And THAT could be a clean guitar signal from earlier in the chain, before any distortion or compression begins to affect the dynamics.

Now, ideally, this thing would be more like a Q-Tron+, which has a buffer input stage (from which the envelope detector is tapped), a send/receive loop into which distortins, etc., can be inserted, and THEN the filtering.  But the arrangement I suggested here allows for adapting the unit to such a scheme, without having to change too much in THIS pedal.  naturally, you'd have to have some splitting of the signal elsewhere to provide that feed to the additional jack, but you wouldn't have to monkey around with this pedal more than the added jack, the trace-cut, and the two added parts (which could be soldered to the jack itself.

[Devius]

Ok, sounds good.
Now how would I incorporate an lfo into this schematic?

[Mark Hammer]

The control on the GGG schematic that is labelled "Level" does not control the volume, but rather introduces some DC to sum with whatever is delivered via R6 from the envelope follower.  The Level control simply divides down the 9v power supply to provide that DC voltage to make the LED brighter or dimmer, and modify the "starting point" of the filter sweep.

That bias/Level control can be used as is, or alternatively you put in a toggle to switch the junction of R13/R15 so that it goes to the output of an LFO and adjusts the amplitude of the LFO output.

How's that?

[Devius]

You're the man, man.