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DIY Stompboxes => Building your own stompbox => Topic started by: Devius on February 23, 2013, 04:53:37 PM

Title: This has probably been schemed up by smarter cookies than me.
Post by: Devius on February 23, 2013, 04:53:37 PM
How about an envelope controlled fuzz for bass.
Thoughts? Ideas?
Title: Re: This has probably been schemed up by smarter cookies than me.
Post by: Mark Hammer on February 23, 2013, 05:09:40 PM
Explain yourself, lad.  What does the envelope control?
Title: Re: This has probably been schemed up by smarter cookies than me.
Post by: Gurner on February 23, 2013, 06:01:32 PM
Quote from: Mark Hammer on February 23, 2013, 05:09:40 PM
Explain yourself, lad.  What does the envelope control?

Working on the limited info available to hand ...I'd say 'fuzz for bass'.
Title: Re: This has probably been schemed up by smarter cookies than me.
Post by: Devius on February 23, 2013, 07:24:28 PM
The filter would control the amount of fuzz into the signal. Simply put, instead of bwow wow it would be growl growl.
I don't know if it is even possible, however if it is I thought I would pick some brains and find the appropriate avenue to explore.
Title: Re: This has probably been schemed up by smarter cookies than me.
Post by: WaveshapeIllusions on February 23, 2013, 08:31:10 PM
That'd be cool. For bass, you'd want a clean signal as well. Mix them in an inverting opamp and use an LDR for the fuzz input resistor. Playing harder mixes more fuzz in. I'd use a resistor in parallel with the LDR to limit the maximum value.

For extra simplicity, you might not even need an envelope follower. Just gain the signal up way high and use LEDs as the clippers, preferrably ones with a low forward voltage.

Shoot, I might have to breadboard this.
Title: Re: This has probably been schemed up by smarter cookies than me.
Post by: Devius on February 23, 2013, 11:44:45 PM
Thats more or less what I had in mind. I would like a guitar version as well but I wanted to make something special for a friend of mine that would be quite unique.
Title: Re: This has probably been schemed up by smarter cookies than me.
Post by: darron on February 24, 2013, 07:23:45 AM
it's difficult to describe i guess. envelopes usually trigger depending on volume. fuzzes already have the 'fuzz' go up as the pick intensity and volume goes up (:
Title: Re: This has probably been schemed up by smarter cookies than me.
Post by: Devius on February 24, 2013, 01:55:15 PM
(http://img812.imageshack.us/img812/7703/blackfuzzops.jpg) (http://imageshack.us/photo/my-images/812/blackfuzzops.jpg/)

Now, this is probably laden with more problems than I could fathom... I think, in a way, it captures what I want it to do.
I would like to toggle fuzz to clean AND clean to fuzz if you understand what I mean.
Title: Re: This has probably been schemed up by smarter cookies than me.
Post by: kodiakklub on February 24, 2013, 02:17:12 PM
what about an EH bassballs or autowah but controlling fuzz? maybe you could adapt the bassballs circuit....
Title: Re: This has probably been schemed up by smarter cookies than me.
Post by: Devius on February 24, 2013, 02:25:37 PM
Thats what I want to do.
Title: Re: This has probably been schemed up by smarter cookies than me.
Post by: Mark Hammer on February 24, 2013, 02:48:21 PM
I suspect devius wants somethng that is like the Toadworks Enveloope: http://www.toadworksusa.com/manuals/Enveloope.opman.p1.pdf
http://www.emusician.com/news/0766/toadworks-enveloope/146412

This product was sadly ahead of its time, and is no longer in production.
Title: Re: This has probably been schemed up by smarter cookies than me.
Post by: Devius on February 24, 2013, 03:27:07 PM
That would basically be it in a nutshell. So much for a unique original idea.
I still want to make it though.
Title: Re: This has probably been schemed up by smarter cookies than me.
Post by: Mark Hammer on February 24, 2013, 03:34:25 PM
I think it is a terrific thing to make, and has uses well beyond what prompted the thread.

Essentially, what you are looking for/at is an envelope-controlled mixer/panner, that will blend seamlessly between a dirty bass tone and a clean one.  BUt this sort of thing could also be used to morph between a wide array of sounds, and doesn't have to be just clean vs something else.
Title: Re: This has probably been schemed up by smarter cookies than me.
Post by: Devius on February 24, 2013, 04:13:50 PM
Okie dokie. You wouldn't happen to have a schematic in that magic hat of yours, would you?
Title: Re: This has probably been schemed up by smarter cookies than me.
Post by: Devius on February 24, 2013, 04:17:21 PM
Take it to the next level. A phase shifter that would shift between phases of different effects. A phase blender if you will.
Title: Re: This has probably been schemed up by smarter cookies than me.
Post by: Mark Hammer on February 24, 2013, 04:56:20 PM
Quote from: Devius on February 24, 2013, 04:13:50 PM
Okie dokie. You wouldn't happen to have a schematic in that magic hat of yours, would you?
Nope, wish I did, but it shouldn't be too hard to whip something up that is functionally equivalent.  Imagine a mixer, where the relative level of each of the two inputs is dictated by their respective input resistances to the mixer.  The envelope follower drives two LEDs, one of which gets brighter with higher input signal, and the other of which starts out bright and gets dimmer as you pick harder (i.e., a normal and inverted output, up and down drive all at the same time).  The LEDs set the LDR values, and bob's your uncle.
Title: Re: This has probably been schemed up by smarter cookies than me.
Post by: brett on February 24, 2013, 06:40:24 PM
Hi
one of the easiest methods of making a mixer/panner is to apply the envelope voltage to the gate of a MOSFET. The MOSFET can either change the signal in-line resistance or bleed some of the signal to ground.
cheers
Title: Re: This has probably been schemed up by smarter cookies than me.
Post by: Devius on February 24, 2013, 09:11:08 PM
Would that require 2 op amp stages from the input buffer, one inverted and the other normal? Would those same op amp stages have the same components, just pins swapped?
Title: Re: This has probably been schemed up by smarter cookies than me.
Post by: Mark Hammer on February 27, 2013, 10:41:01 AM
After pondering this a bit, it got me thinking about an envelope-controlled, or rather amplitude-controlled, switch; essentially a flip-flop that responds to peaks above some threshold.  Hit a string or two hard, and the flip-flop state changes, and hangs in there until the next similar peak, at which point it switches state again.  Everything in between is processed in either A or B mode, whatever happens to be in those to modes.

What I'm trying to get past here is the problem of A/B/A transitions happening in ways that are a little too "busy" or frequent.

I'm guessing there is inevitably a comparator here, to trigger the flip-flop with a preset level?
Title: Re: This has probably been schemed up by smarter cookies than me.
Post by: ~arph on February 27, 2013, 10:55:29 AM
I am actually in the process of cooking up something similar:

https://dl.dropbox.com/u/1849818/published_images/envelope-blend.png (https://dl.dropbox.com/u/1849818/published_images/envelope-blend.png)

It's not 100% verified, but it basically blends in an effect on the decay of the note. If you want this to follow the original envelope instead you should reverse the envelope going into the inverting opamp that drives the led for the LDR. One could accomplish this by making the Q1 buffer inverting.

I'm using a window comparator for the max and minimum level detection plus some hysteresis to prevent unwanted triggering.

I'll post this as a project when it's done.

Title: Re: This has probably been schemed up by smarter cookies than me.
Post by: Mark Hammer on February 27, 2013, 12:44:31 PM
Thanks!  :icon_biggrin:  Looks like a well thought-out project, and likely to be useful.

I don't know about other folks, but I like circuits that make me rethink how I use effects.  And this seems like one such circuit.  I look forward to its completion.