[sdiy] Pots vs Encoders, was Re: [sdiy] dave smith *instruments*

[Dave Manley]

Tom Wiltshire wrote:
>
> I accept that a panel full of encoders and a single LCD screen isn't 
> much competition for pots, since the pot positions sometimes show you 
> something useful, and only the encoder whose value is on the LCD tells 
> you anything. But this isn't really comparing like with like, although 
> that is the situation on the P08 or Evolver, which is where we came in.
There's an implication in this thread that encoders cant be used as 
performance controls and that's silly.  They can but with their inherent 
limitations.  Positional feedback isn't always necessary - I want a 
slower attack, I want more resonance, I want.... - that's just turn a 
dedicated or assignable encoder left or right.  The Mopho/Tetra for 
example has dedicated encoders for common performance parameters, the 
other encoders are patch assignable to what ever you want.  So pick your 
preset, listen to the sound, and tweak away.  The Mopho/Tetra interface 
also makes it really easy to reassign an encoder in real time, but you 
do have to scroll through the parameter list, so it does take attention.

I was just testing a Mopho looking at the overall quality and the rotary 
encoder issues you describe.  A few comments:

1. The rotary encoders are 24-step.  I believe this is the part: 
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=P10860-ND
2. They have a very solid feel, The data sheet says they're rated for 
30K operations for what's that worth.
3. Testing the 'Osc Fine Freq' setting that has a range of -50 to +50, 
if you spin the knob 360 degrees in about 2 seconds or less the display 
will smoothly increment and show a change of 24 ticks
4. If you spin the knob in about 1 second the display will change from 
-50 to +50, skipping most or all intermediate values
5. Spinning the knob as quickly as possible ~360 degres results in 
unpredictable response, either no change, max change, or anything in 
between.
6. If I put the knob at min value, and then turn counter-clockwise as 
fast as possible occasionally the display will take a value between -50 
and -45, indicating some misreads.
7. With a little practice you can get a 'click feel' and could probably 
get quite skilled at turning a knob and getting exactly so many 'clicks'.

I don't see any glitchy behavior.  Not denying that others see it, or I 
won't see it in a year on this Mopho, just reporting what it currently does.

-Dave