Lex Strymon - Clone or Similar?

[buildafriend]

Hi guys,

A friend is asking me if we can build said pedal. I know nothing about it and don't see a schematic.. it also looks new so I don't know what data about it is out there.

Any advice? Maybe there is something very similar available via schematic?

All the best,

[dschwartz]

Strymon etfects are all DSP. I don't think you can clone those.

[MJ_Sound_Cubed]

Good to know.

Strymon etfects are all DSP. I don't think you can clone those.

[AdamFenwickSymes]

As dschwartz said, you're not going to be able to clone a DSP-based pedal.

There are a lot of Lesley imitation pedals though, going all the way back to the Uni-vibe. You could go through a bunch of them until you found an analog one you liked and clone that.

[Mark Hammer]

Rotary emulation is a topic that routinely comes up here a few times a year, and we routinely engage in discussion about what makes for best emulation.

Sometimes, what people really want from a rotary emulator is really just the ramp-up/ramp-down aspect.  That is, if the effect can gradually speed up, on demand, that's pretty much good enough for them, and it doesn't really mater to them how it's being done or even what the modulated effect is.  It could be a ramped phaser, chorus, flanger, vibe, or whatnot.

In other cases, some want a specific rotary sound (e.g., slow Leslie, or bubbly fast sound), but don't care or use the ramping feature.  In still other cases, people aim for the the tone of the tube power-stage clipping they get from a big organ cabinet.  And, in still other cases, people want the spatial swirl, with the tone being a notch down from that.

So, even setting the DSP aspect aside, your friend needs to specify what it is they want from a "rotary speaker sound".  I gather the Lex does all of that, including the spatial swirl (if you use two amps).  But if your friend only really wants some, but not all of it, then that will help to identify a reasonable, and achievable, emulator circuit.  For instance, many phasers and choruses can be adapted for ramp-up/ramp-down with a circuit RG Keen posted some years back.

[ElectricDruid]

That suggests another idea for a digital LFO, Mark: A "Leslie LFO" with a "fast" and a "slow" rate knob and a switch to ramp between them. Bonus points if you can include features that mimic the way the two separate rotors on a real Leslie behave.

That'd deal with a lot of the mechanics, and it'd leave people free to do the modulation part however they see fit; phaser-based, OTA, optical, BBDs, whatever. It's never going to be a super-simple circuit, but wrapping all the LFO complications into one chip might keep it reasonable.

[jubal81]

Haven't built it, but Diablochris designed a nice one called Vomit Comet.

[Mark Hammer]

That suggests another idea for a digital LFO, Mark: A "Leslie LFO" with a "fast" and a "slow" rate knob and a switch to ramp between them. Bonus points if you can include features that mimic the way the two separate rotors on a real Leslie behave.

That'd deal with a lot of the mechanics, and it'd leave people free to do the modulation part however they see fit; phaser-based, OTA, optical, BBDs, whatever. It's never going to be a super-simple circuit, but wrapping all the LFO complications into one chip might keep it reasonable.

Ramp speed would be an additional feature.   In true mechanically-rotating speakers, the ramp up/down time is a function of the physical inertia of the belt system, and how long it physically takes to go from speed A to speed B.  As such, the ramp time depends on the contrast between the fast and slow speeds.  In an electronic emulation, if we use RG's circuit or the Roland AP-5 as examples, ramp-time is a function of how long it takes to charge up or discharge a cap.  Doing it digitally would allow for ramp-time being decoupled from the difference between fast and slow speed.  It would also allow for ramp rates that are not normally found in physical Leslies.  For example, a very gradual build up of speed.  Finally, if you were to use the same PIC you favour four A-D inputs allows for pots to control ramp-up time, ramp-down time, fast speed and slow speed.  So imagine a very slow swirl as the always-on effect.  Hit the ramp switch, and the modulation rate gradually builds and builds, as if you were subtly working an expression pedal, until it reaches some predetermined faster modulation rate.  Hit the switch again, and it could instantly drop back down to the default slow swirl.  That's the beauty of having separate ramp-up and ramp-down rates.

Thanks for the idea!