[sdiy] quantizer questions..(Ray Wilson model just built)

Sun Sep 21 22:29:48 CEST 2008

Hi Dan

I suggest that you put a linear ramp into the input that goes from 0 to 6.5 
volts. Set the switches so that you are in 1/2 step mode. Remember that the 
fourths mode switch will take precedence so you have to be in the half/whole 
position on that switch to test half and whole step mode. Then observe the 
output on a scope (similar to what I did in the YouTube). The steps should 
be similar in amplitude (.0833 V after calibration). Adjust your scope so 
that you are triggering on the falling edge of the resultant waveform out of 
the quantizer (like in the YouTube). Adjust the vertical and horizontal 
controls so that you get one scope screen for the entire ramp. As you change 
modes you should see half as many steps for whole mode and then half again 
for fourths mode (like in the YouTube). If you are not seeing the signal 
follow the ramp or you are seeing the voltage change in non-equal steps I 
suspect that one or both D-to-As have a wrong value resistor(s). You did use 
CD40XX logic right and not 74HC or anything like that? Op amps are all OK? 
All components present and soldered? Check the wiring around the mode 
switches it could also be the culprit.

The only time you would add any jumpers is if you only want to use half step 
mode. The jumpers for that are explained near the parts layout.

With no inputs and just adjusting the initial voltage pot you should get 
about 3 1/2 octaves of notes from fully off to fully on. Also, all of the 
notes (in the three octaves) should be present. In Whole step mode you will 
get 1/2 as many steps but still about 3 1/2 octaves in fourths mode 1/2 as 
many again but definitely a lot more than four.

Long distance trouble shooting is never 20/20 so if there is another pair of 
eyes that can help you closer to home it would be a good thing.

Good luck

Ray

----- Original Message ----- 
From: "Dan Snazelle" <subjectivity at hotmail.com>
To: "Ray Wilson" <raywilson at comcast.net>; <synth-diy at dropmix.xs4all.nl>
Sent: Sunday, September 21, 2008 1:53 PM
Subject: RE: [sdiy] quantizer questions..(Ray Wilson model just built)

ok

i am only getting 4 distinct voltages when i turn the pot.
i tried calibrating but this changed nothing.

could i be stuck in 4ths mode?

is there a JUMPER ON THE BOARD I COULD HAVE MISSED? (IS that one near the 
tl071??)

thanks

those samples really helped!!

thanks all

--------------------------------------------
check out various dan music at:

http://www.myspace.com/lossnyc

http://www.soundclick.com/lossnyc.htm

http://www.indie911.com/dan-snazelle
(or for techno) http://www.myspace.com/snazelle

> From: raywilson at comcast.net
> To: raywilson at comcast.net; subjectivity at hotmail.com; 
> pfperry at melbpc.org.au; synth-diy at dropmix.xs4all.nl
> Subject: Re: [sdiy] quantizer questions..(Ray Wilson model just built)
> Date: Sun, 21 Sep 2008 10:52:08 -0600
>
> Samples are now on the web page for the Quantizer (YouTube is on the way).
>
> Cheers
>
> ----- Original Message -----
> From: "Ray Wilson"
> To: "Dan Snazelle" ; "Paul Perry"
> ;
> Sent: Sunday, September 21, 2008 8:12 AM
> Subject: Re: [sdiy] quantizer questions..(Ray Wilson model just built)
>
>
>> The Voltage Quantizer's initial voltage pot is similar to what Paul
>> suggested. If you just connect the quantizer's output to a VCO for 
>> example
>> and adjust the initial voltage pot from low to high you will hear the
>> effect of the quantization on the voltage coming from the pot (which is
>> wired as a variable voltage divider). So in 1/2 step mode you will hear
>> the oscillator rise in pitch in discrete 1/2 step intervals. When I refer
>> to half step I mean C, C#, D, D#, E, F, F#... etc. Whole steps would be:
>> C, D, E, F#, G#, A#, C... etc. Fourths mode would be: C, E, G#, C... etc.
>> The switches for 1/2 step, whole step, and fourths act immediately 
>> because
>> they change the configuration of the output D to A. The quantizer is 
>> meant
>> to follow voltages changes in the range of very low frequency to about 
>> 400
>> HZ. For example a sequencer running a sequence is typically about 2 or
>> three notes a second. A S&H is similar but sometimes up to 10 to 20 notes
>> a second. Once you start putting audible frequencies into the input the
>> output starts to become more wave like (still consisting of discrete
>> samples of the input but more cyclic in nature). So ideally if you want
>> the effect of random notes from the 12 tone scale (or whole or fourth 
>> note
>> scales) you want your S&H or sequencer to be changing at a rate that is
>> sub audible (20 HZ or less). You also need to make sure the input voltage
>> is in the range of 0 to +7 volts. Negative voltages will not be quantized
>> and the unit will simply output it's lowest voltage. (.08333 in 1/2 step
>> mode, 0 in other modes).
>>
>> You won't hurt the unit by applying out of range synth level voltages.
>> (e.g. -10V to +10V). The unit quantizes voltages in the range of 0 to
>> about 7 volts. It will not quantize negative voltages. So be sure to 
>> apply
>> offset to the signal being fed in to bring it into the 0 to +7V range.
>>
>> Cheers and good quantizing.
>>
>> Ray
>>
>>
>>
>> ----- Original Message -----
>> From: "Dan Snazelle"
>> To: "Paul Perry" ;
>> Sent: Sunday, September 21, 2008 5:08 AM
>> Subject: RE: [sdiy] quantizer questions..(Ray Wilson model just built)
>>
>>
>>>
>>> by complexity, what i meant was this. into a 1/voct input i would put
>>> something in that i was sure would trigger it. (a signal with peaks and
>>> valleys) and it would just put out one or two notes. annoying as hell.
>>>
>>> then as i said i tried the linear input..wow
>>>
>>>
>>> i assume its made to work with linear inputs...i didnt do anything wrong
>>> now did I?
>>>
>>> thanks for the help.
>>>
>>>
>>>
>>> --------------------------------------------
>>> check out various dan music at:
>>>
>>> http://www.myspace.com/lossnyc
>>>
>>>
>>> http://www.soundclick.com/lossnyc.htm
>>>
>>>
>>> http://www.indie911.com/dan-snazelle
>>> (or for techno) http://www.myspace.com/snazelle
>>>
>>>
>>>> From: pfperry at melbpc.org.au
>>>> To: synth-diy at dropmix.xs4all.nl
>>>> Subject: RE: [sdiy] quantizer questions..(Ray Wilson model just built)
>>>> Date: Sun, 21 Sep 2008 17:16:44 +1000
>>>>
>>>> More simply, the input signal may not be covering the entire range.
>>>>
>>>> As for complexity..
>>>> The output from a quantizer is going to be LESS complex thatn the 
>>>> input,
>>>> because while the input signal can have any voltage over a range, the
>>>> quantizer has only a limited number of defined voltages outout - that 
>>>> is
>>>> what a quantizer is!
>>>>
>>>> The point to doing quantizing, is to turn a continuous varying signal
>>>> into a
>>>> series of notes. It seems as though it is doing that, allright.
>>>>
>>>> I'd make a "test voltage" from a 9v battery and a pot, so I could dial
>>>> from
>>>> 0 to +9V, you should get the full range of notes from 0 to 6V, then 
>>>> just
>>>> the
>>>> highest.
>>>>
>>>> Mind you, I haven't built one yet..
>>>>
>>>> paul perry melbourne Australia
>>>>
>>>>
>>>>
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