Dr Scientist Tremolessence
Posted: 09 Jul 2009, 15:14
Was looking around fr some info and came across this:
And this from Ryan at Dr Scientist:
Hi gents! Thanks very much for the nice comments and the support, we sure appreciate it!
I'd be happy to shed some light on the similarities between The Tremolessence and the Semaphore, although I've never actually seen one in person.
I think a lot of us with electronics training (I have a diploma in EET) probably draw from a similar bag of tricks, as there's a few great ways to do everything in the world of audio effects.
For a tremolo effect we need an oscillator...something to make a waveform that will affect an audio signal in the way we want. There's lots of ways to get a waveform...you can use transistors, opamps, timers, even specialty chips that exist solely to make waveforms.
My favourite way is using opamps, in a Schmitt trigger/Integrator setup. One half of a dual opamp gives you a square wave, the other side makes that into a triangle wave. You just need a way to switch between the two.
The rate in a setup like that is determined by a resistance and a capacitance, but it's hard to get a really wide range of control with just one cap and one potentiometer, so to go really slow and also really fast we need to switch between a choice of capacitors.
The shape control is a common oscillator trick using steering diodes to pull the waveform in different directions and change its duty cycle.
The actual volume modulation of the circuit is provided by a very bright LED shining on a special resistor whose resistance changes depending on the light level it receives. It's called an opto-coupler and the Tremolessence is an optical tremolo effect.
I imagine all designers have their own tricks for handling audio..I like to use opamps and I like to keep those parts as clean and simple as possible.
Bottom line, The Tremolessence uses analog circuitry that has been around for decades. I didn't mean to step on any body's toes with the design, it's my take on a classic design done in the way that I think sounds best and is most functional.
Anybody have any better gutshots?
I'm trying to work out a deal with a Semaphore, with any luck I'll have it up here soon.
And this from Ryan at Dr Scientist:
Hi gents! Thanks very much for the nice comments and the support, we sure appreciate it!
I'd be happy to shed some light on the similarities between The Tremolessence and the Semaphore, although I've never actually seen one in person.
I think a lot of us with electronics training (I have a diploma in EET) probably draw from a similar bag of tricks, as there's a few great ways to do everything in the world of audio effects.
For a tremolo effect we need an oscillator...something to make a waveform that will affect an audio signal in the way we want. There's lots of ways to get a waveform...you can use transistors, opamps, timers, even specialty chips that exist solely to make waveforms.
My favourite way is using opamps, in a Schmitt trigger/Integrator setup. One half of a dual opamp gives you a square wave, the other side makes that into a triangle wave. You just need a way to switch between the two.
The rate in a setup like that is determined by a resistance and a capacitance, but it's hard to get a really wide range of control with just one cap and one potentiometer, so to go really slow and also really fast we need to switch between a choice of capacitors.
The shape control is a common oscillator trick using steering diodes to pull the waveform in different directions and change its duty cycle.
The actual volume modulation of the circuit is provided by a very bright LED shining on a special resistor whose resistance changes depending on the light level it receives. It's called an opto-coupler and the Tremolessence is an optical tremolo effect.
I imagine all designers have their own tricks for handling audio..I like to use opamps and I like to keep those parts as clean and simple as possible.
Bottom line, The Tremolessence uses analog circuitry that has been around for decades. I didn't mean to step on any body's toes with the design, it's my take on a classic design done in the way that I think sounds best and is most functional.
Anybody have any better gutshots?
I'm trying to work out a deal with a Semaphore, with any luck I'll have it up here soon.