Which pedals to construct a pseudo guitar synthesizer

[pandadandan]

I recently decided to construct a bunch of pedals in the hope of creating some menacing low-pass filtered heavy bottomed sounds.

After checking the searches, it seems a good start point would be:

Rocktave > (waveshaper?) > Ring Mod > Filter (Neutron/Meatball) > Envelope (slow gear?) > Usual guitar effects (fuzz/phase/trem/flange) > Delay.

Now, bearing in mind I want something moderately resembling a synth sound, is this a good setup?
What would you change, order-wise?

I don't know if there would be anything to take the square Rocktave output and convert it to tri/sine/pwm.
Envelopes would be another thing. I guess it's mainly the attack that needs caring for, so a slow gear might be fine, but maybe there's some other solutions.

For a HUGE low-pass sound, which filter would you recommend?

So many questions.....!

[oskar]

Search here for the Shocktave snd Slacktave.
First gives one octave down saw and the other one and two octaves down of squarewaves.

[Mark Hammer]

I recently decided to construct a bunch of pedals in the hope of creating some menacing low-pass filtered heavy bottomed sounds.

After checking the searches, it seems a good start point would be:

Rocktave > (waveshaper?) > Ring Mod > Filter (Neutron/Meatball) > Envelope (slow gear?) > Usual guitar effects (fuzz/phase/trem/flange) > Delay.

Now, bearing in mind I want something moderately resembling a synth sound, is this a good setup?
What would you change, order-wise?

I don't know if there would be anything to take the square Rocktave output and convert it to tri/sine/pwm.
Envelopes would be another thing. I guess it's mainly the attack that needs caring for, so a slow gear might be fine, but maybe there's some other solutions.

For a HUGE low-pass sound, which filter would you recommend?

1) For maximum filter "impact", you will want a sound which more closely approximates an oscillator; i.e., something which produces a fairly constant-level square wave, rather than a "normal" guitar tone that loses harmonic content and level quickly.  You should be able to do that with either a Bluebox or a Rocktave.

2) Since such a sound source would instantly obliterate any actual amplitude envelope properties, if you want to use an envelope-controlled filter of some sort, you will need to tap the envelope signal from the point before the square-wave/octave generation, where there is more dynamic properties to the signal.

3) Most folks would recommend some version of a diode-ladder 4-pole lowpass filter for sounds in the Minimoog zone.  There are innumerable variations on this circuit posted around.  I should think that two separate filters, one for an octave down and the other for 2 octaves down, might produce a bigger sound.  If one of the octaves is chorused or pitch-modulated separately, that would yield even more modulation glory and a fatter sound.  For that matter, I would imagine that simply sticking a couple of fixed allpass stages between the output of the lower octave and the point where everything is mixed to mono would create some intersting acoustic properties by slightly staggering the signals to mimic several separate sources.

4) Take a gander at Colin's Experimentalists Anonymous schematic archive: http://experimentalistsanonymous.com/diy/ .  Lotsa good contenders there, including an entire guitar synth project w/PCB (in the OOP Japanese collection directory).  The synth project requires a hard0to-get TA7125P but this site shows how to make a semi-discrete replacement for it: http://www2.odn.ne.jp/chietronix/TA7125P.pdf.

[pandadandan]

1) For maximum filter "impact", you will want a sound which more closely approximates an oscillator; i.e., something which produces a fairly constant-level square wave, rather than a "normal" guitar tone that loses harmonic content and level quickly.  You should be able to do that with either a Bluebox or a Rocktave.

2) Since such a sound source would instantly obliterate any actual amplitude envelope properties, if you want to use an envelope-controlled filter of some sort, you will need to tap the envelope signal from the point before the square-wave/octave generation, where there is more dynamic properties to the signal.

3) Most folks would recommend some version of a diode-ladder 4-pole lowpass filter for sounds in the Minimoog zone.  There are innumerable variations on this circuit posted around.  I should think that two separate filters, one for an octave down and the other for 2 octaves down, might produce a bigger sound.  If one of the octaves is chorused or pitch-modulated separately, that would yield even more modulation glory and a fatter sound.  For that matter, I would imagine that simply sticking a couple of fixed allpass stages between the output of the lower octave and the point where everything is mixed to mono would create some intersting acoustic properties by slightly staggering the signals to mimic several separate sources.

4) Take a gander at Colin's Experimentalists Anonymous schematic archive: http://experimentalistsanonymous.com/diy/ .  Lotsa good contenders there, including an entire guitar synth project w/PCB (in the OOP Japanese collection directory).  The synth project requires a hard0to-get TA7125P but this site shows how to make a semi-discrete replacement for it: http://www2.odn.ne.jp/chietronix/TA7125P.pdf.

Thanks for the detailed reply!
I thought the Rocktave would be my best bet as a sound source for the project, so thanks for cementing that plan.

In regards to the 4-pole ladder filter, has this been successfully stompboxerized by anyone yet and if so are there any pcbs available?  Or actually would it make more sense to obtain the CGS guitar > synth signal converter module with an actual moog-style filter connected up, then bunged in a stompbox?

Sounds like fun times ahead!

[soggybag]

The Ugly Face can produce a constant square wave, it also has a sort of envelope built in. It's an easy build and sounds very synthy.

[Foxpaw]

Another vote for the ugly face!
I think an instabil fuzz (Skyripper fuzz?) could make some synthy sound to. (Extreme oscillating -> octave up/down)

[The Tone God]

Forsaken ?

Andrew

[Processaurus]

Some ideas on creating a pseudo  two oscillator sound with Tim Escobedo's PWM, should be low parts count:

http://www.diystompboxes.com/smfforum/index.php?topic=54460.msg416442#msg416442

[widdly]

For filter circuits check out the Wasp clone synth on Elby designs.  There are two filter schematics there that might be useful because they run of a single sided supply.

[pandadandan]

Some ideas on creating a pseudo  two oscillator sound with Tim Escobedo's PWM, should be low parts count:

http://www.diystompboxes.com/smfforum/index.php?topic=54460.msg416442#msg416442

Wow that sounds handy! My idea was to see if I could have two outputs to the Rocktave, one of which was modulated with such an lfo for the duty cycle.  I'd then sling a mixer in the setup to join em back together after a bit of chorus/delay etc on one of the lines.  This seems like a simpler proposition!

For filter circuits check out the Wasp clone synth on Elby designs.  There are two filter schematics there that might be useful because they run of a single sided supply.[\quote]
Ooooo I didn't know the Wasp runs on a single sided supply.  Very interesting!


I'm avoiding the Uglyface as I want a little more control over the sounds etc.  It is an awesome circuit though.  As far as insane fuzz, I've got my Noise Swash to rupture eardrums with.

Thanks for everyone's contribution and help!