I was just thinking… wouldn’t it be cooler if the knobs were endless… that way you dont run out of knob with the led marker up at half way…
This is a cool idea, but I don’t know of any cheap technology to replace pots.
If you tried to use endless knobs, you wouldn’t be able to have genuine analog response for the knobs. Endless knobs send increase or decrease values digitally. Analog knobs decrease or increase electrical resistance.
Yes, it would be incompatable with RAC.
But if the knob was sampled at a high enough rate, and D/A’d back into the RAC, I don’t think anyone could possibly know the difference.
Of course just the thought that this is happening would drive some folks crazy.
The largest number of steps I’ve seen on a digital pot is 256 (8 bits). Not really enough for a smooth sweep.
Anyone seen any digital pots with more? Some of those VA synth are pretty smooth, so they must exist.
Native Instruments Kore controller has endless knobs with “500 steps per revolution”
-craig
Are the pots on the Voyager analogue or are they digital? I thought I had heard that they were not analog but had a high digital resolution. The Alesis Ion has 12 bit endless knobs. Thats 4096 values I believe.
Nope, they’re all analog. The valued that’s stored as a preset is digital. When the preset is recalled, this stored value is sent back to whatever parameter its controlling. However, when the user turns a knob, analog control kicks in and the parameter jumps to the value determined by the analog pot. All analog control.
The following quote is from Sound On Sound magazine from November 2004:
“Next, I would like to point out another slight deficiency that has become apparent on all Voyagers. The synth’s manufacturers claim that the 12-bit A-D converters used to translate the positions of the front-panel knobs into digital values, the interpolation of those values when the CVs are generated, and the scanning speed of the front panel are all sufficient to ensure that the Voyager is indistinguishable from a pure analogue synthesizer. However, this is not the case. To discover this for yourself, just sweep two knobs simultaneously while listening to a patch. If one of the parameters you’re adjusting makes obvious changes to the sound — say, the filter cutoff frequency — you will hear audible stepping. To be fair, the amount of ‘zippering’ is very small, and will bother almost no-one, but it’s there nonetheless.”
The Voyagers knobs are digital. As far as I know, the Little Phatty is the first synth ever to have knobs that are both analog and digital.
On other notes, some synths attempt to counteract the stepping of midi values by adding slew to control changes. Some synths, however, have very obvious stepping going on. Check out the resonance control on the new Korg MicroX: blatant stepping. Other synths use NRPN or RPN numbers for higher resolution. The Korg EA-1 has a much nicer sweep to it.
I, for one, am very happy that Moog came up with this new technology that means you can have saved patches and have direct analog control of your synth also. There’s nothing like a manual filter sweep that’s totally smooth.
Hmmm, I was under the impression that they were analog and only the value was stored then transmitted back to the parameter. Wonder where I got that idea…
Well, if the knobs are digital they certainly show no audible zippering! Had me fooled!
Well, to be truly accurate, the knobs themselves on the Voyager are analog. Their position gets converted into digital values so that they can be stored as midi data, then the data is converted into CVs to drive the analog circuitry. With the Little Phatty, they’ve somehow figured out how to switch off between digital values, and direct analog control of the circuitry.
I’ve thought about this quite a bit. I assumed this is how the Voyager’s knobs worked, but it sounds like its closer to how the LP’s knobs work.
Here’s how I would do it, I don’t know how they really work, but humor me.
So you have an analog pot, it controls a parameter directly according to whatever it is routed to. When saved, this analog value is run through an ADC and stored in a microprocessor. When a preset is recalled, this stored value comes from a DAC and sent to the parameter and AT THE SAME TIME the current position of the knob is stored in the same way mentioned earlier. The mircoprocessor constantly polls the ADC from the pot to see if this value ever changes. If it does, the microprocessor releases the parameter from it cold, digital grasp and the it snaps to the analog value.
I may be way off, but thats just how I’d do it.
Yes, Oyster Rock, I’m certain that is what happens in the LP.
What I propose is putting a cheap processor (under $1) on each knob, or say a pair of knobs depending on computing resources needed.
The knob could then be sampled at 10Khz and 12 bits resolution, processed (no more need for snap, track,passthru modes), then fed to the exising RAC circuitry.
I think a knob with 4096 steps would be perceived as very smooth.
Until a knob or pot like device without stops that can be sampled is found, this is just a conjecture.