Doepfer

Thanks Florian!  I knew I asked in the right place.  That helped a
lot.  The t&h vs s&h was something I was definitely missing.

I was thinking the a152 will do a lot for me as a cv record & playback
"sequencer," mainly because of the built-in 8 way multiplexer.  But
then I just realized, while it will save 8 voltages, the next time it
is addressed/switched via clock signal, the voltage is replaced.

I am thinking about this setup for a cv-recorder:

Put a s&h (a145) before the cv-in on the t&h (a152).  This will sample
the incoming signal from the keyboard.

Put a gate inverter (a165) before the clock-in on the t&h.  After a
gate signal is released on the keyboard, this will tell the t&h to
advance to the next address and store the current s&h voltage.

I also see there is a DIY modification to make the a152 work like an
s&h module without these extra modules, thought it may need a short
trigger delay.

For play back:

Either another t&h (a152) utilizing just the just multiplexing switch
sub unit or a sequencer (a155).  Both would require all the individual
s&h outs patched to the stepped/addressed cv-ins.

What do you think?

On Fri, Jun 19, 2009 at 9:08 AM,
achtung_999<heinrich.himmelwasser@gmail.com> wrote:
>
>
> Great explaination Florian!
>
> On Fri, Jun 19, 2009 at 12:25 PM, Florian
> Anwander<fanwander@mnet-online.de> wrote:
>>
>>
>> Hi Greg
>>
>>> I'm not sure I fully understand track & hold, so I thought I'd ask...
>>>
>>> I am thinking of using the t&h module with a clock divider and a
>>> roland sh-2. First, record in a series of voltages from the sh-2
>>> keys, then have the track&hold play them back. With the clock divider
>>> triggering it every 4 beats or so, it would act like a recordable one
>>> bass note per measure sequencer of sorts.
>>>
>>> Would that work? Or is there a better way to record(track/sample)
>>> simple sequences of voltages?
>> If I understand you correctly: Yes and No.
>>
>> Basically you are asking some module, which holds certain voltage
>> values. Both (S&H and T&H) do this.
>> The difference between "Sample and Hold" and "Track and Hold" is, how
>> the behave on changes of the ingoing control signal.
>>
>> S&H:
>> After powering the module/system up, a Sample&Hold "listens" to the
>> input voltage. The output is 0V. As soon as the control signal changes
>> from low(=0V) to high(=5V) the input voltage will be stored in the
>> S&H-stage and offered at the output. It does not matter, whether the
>> controlsignal is still up or down, and doesn't matter alos whether the
>> input signal is changing or not.
>>
>> T&H:
>> After powering the module/system up, also a Track&Hold "listens" to the
>> input voltage. The output is 0V. As soon as the control signal changes
>> from low(=0V) to high(=5V) the input voltage will fed through to the
>> output. The output now will change with the input as long as the control
>> signal is high. This is the "Track"-mode: the output tracks the input.
>> As soon as the control signal changes back from high to low, the output
>> signal (which was changing before) will be freezed at the momentary
>> voltage.
>>
>> If you compare it to the world of pictures, the S&H is like a photo
>> camera, which picks that actual moment. The T&H is similar like a video
>> which is sometimes playing sometimes paused.
>>
>> So: for youre "sequencer" request: yes, multistage S&H and(!) T&H can
>> behave like a sequencer, but in recording mode the S&H will behave more
>> like expected than the T&H.
>>
>> Florian
>>
>>
>
>