boosting certain frequencies... [turns out to be an FSH-1 mod]

[birt]

I have this sound in my head and i wonder if it is possible.
a pedal with an envelope cotrolled LFO that boosts certain "parts" of the signal at the speed of the LFO wich decreases as the note dies.

So you hit a chord or note and the pedal starts boosting frequencies that are present in that chord or not. But it switches frequencies randomly. First very fast and slower when the volume of the chord decreases.

[Mark Hammer]

If I've understood you correctly, you are NOT looking for what the Maestro Sample and Hold over at  GGG (and U-Stomp) does, where there is either envelope swept filtering, OR clock-driven filtering.  Rather, the cente-frequency of a resonant boost moves around, sort of like a sample & hold device, but the clock rate itself is envelope-driven.

In some respects, the FSH-1 could be co-opted to do what you are imagining.  What you would need to do (at a conceptual level) would be the following:

1) The 2meg speed pot on the FSH-1 would be paralleled by an LDR so that speed could be automatically adjusted.

2) The envelope folower would be redirected from the filter itself to an LED driving the speed LDR.  The time constants of the follower would need to be adjusted to have a slower decay.

3) The bandpass output of the filter section would need to be mixed in with the straight signal so that you always had full bandwidth, in addition to the little resonant bump from the filter.  This would involve a mixer section added to the FSH output.

4) The resonance would need to be bumped up a bit (use Tonda's mod) to make the shift in resonant emphasis a little more noticeable.

What you end up with is a pedal that moves a resonant emphasis around randomly at some constant rate preset with the pot, and then speeds up that movement when you play.  There can be other refinements, but I think we're moving in the desired direction.

[birt]

If I've understood you correctly, you are NOT looking for what the Maestro Sample and Hold over at  GGG (and U-Stomp) does, where there is either envelope swept filtering, OR clock-driven filtering.  Rather, the cente-frequency of a resonant boost moves around, sort of like a sample & hold device, but the clock rate itself is envelope-driven.

In some respects, the FSH-1 could be co-opted to do what you are imagining.  What you would need to do (at a conceptual level) would be the following:

1) The 2meg speed pot on the FSH-1 would be paralleled by an LDR so that speed could be automatically adjusted.

2) The envelope folower would be redirected from the filter itself to an LED driving the speed LDR.  The time constants of the follower would need to be adjusted to have a slower decay.

3) The bandpass output of the filter section would need to be mixed in with the straight signal so that you always had full bandwidth, in addition to the little resonant bump from the filter.  This would involve a mixer section added to the FSH output.

4) The resonance would need to be bumped up a bit (use Tonda's mod) to make the shift in resonant emphasis a little more noticeable.

What you end up with is a pedal that moves a resonant emphasis around randomly at some constant rate preset with the pot, and then speeds up that movement when you play.  There can be other refinements, but I think we're moving in the desired direction.

this part i don't understand (probably because my english isn't good enough)


and wich part of the schematic is the envelope follower? is it usable as just a building block in other pedals too? because i would also like to do the envelope controled rate on a tremolo.

[Mark Hammer]

If you are looking at the FSH-1A schematic at generalguitargadgets, then it is the subcircuit built around IC3.  It is that portion between R15 and R19.

And yes, it is almost identical to what can be used to envelope-control other things like tremolo.

[birt]

ok it's the part of the circuit i thought it was. I'm learning
now the envelope follower is connected to the sw1 and controls the bias of Q3? so the other part of the switch must be the LFO (IC4 and IC5)?

how can i connect a led to the LFO? just put it between 9V and the part of the EF that is connected to the switch? with a resistor in series or something like that?

if i get this right, it would be cool to put an envelope driven ldr in an enclosure so you can use it instead of an expression pedal or something like that.

[Mark Hammer]

ok it's the part of the circuit i thought it was. I'm learning
now the envelope follower is connected to the sw1 and controls the bias of Q3? so the other part of the switch must be the LFO (IC4 and IC5)?

how can i connect a led to the LFO? just put it between 9V and the part of the EF that is connected to the switch? with a resistor in series or something like that?

if i get this right, it would be cool to put an envelope driven ldr in an enclosure so you can use it instead of an expression pedal or something like that.

What you can do (assuming we are still adapting the FSH-1A) is instead of connecting the envelope voltage available at R19 to the switch, it would go to an LED, which then goes to ground.

[birt]

ok it's the part of the circuit i thought it was. I'm learning
now the envelope follower is connected to the sw1 and controls the bias of Q3? so the other part of the switch must be the LFO (IC4 and IC5)?

how can i connect a led to the LFO? just put it between 9V and the part of the EF that is connected to the switch? with a resistor in series or something like that?

if i get this right, it would be cool to put an envelope driven ldr in an enclosure so you can use it instead of an expression pedal or something like that.

What you can do (assuming we are still adapting the FSH-1A) is instead of connecting the envelope voltage available at R19 to the switch, it would go to an LED, which then goes to ground.

thanks for the wonderfull info. i will try this when i get to build an FSH-1 (wich will happen but not very soon since i don't have much tim to solder lately). I will probably build the tonepad version with their mods and put the mod discussed in this topic on a switch too. maybe someone can try it  on an already built FSH-1.

i will also try the envelope followed speed in some other effects.

[hank reynolds 3rd]

Envelope controlled Sample and Hold  

how about splicing in the envelope follower (instead of the original maestro one) from the mcmeat/meatball??? It's got attack, decay,intensity and up and down sweep (so this would give fast----> slow as note dies out, and vice versa) ....
Hmmmm, I already built the fs and h ,but it was always too big to put in a box....Looks like I've got something else to add to 'The List' again 

[birt]

Envelope controlled Sample and Hold  

how about splicing in the envelope follower (instead of the original maestro one) from the mcmeat/meatball??? It's got attack, decay,intensity and up and down sweep (so this would give fast----> slow as note dies out, and vice versa) ....
Hmmmm, I already built the fs and h ,but it was always too big to put in a box....Looks like I've got something else to add to 'The List' again 

on the tonepad project are mods to add those things to the maestro envelope follower. but it might be easier to just use an other one as you say. And maybe you could also use a better filter than the maestro