Doepfer

And by a145 i mean a148...

On Fri, Jun 19, 2009 at 11:06 AM, Greg Cerveny<greg.cerveny@gmail.com> wrote:
> 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
>>>
>>>
>>
>> 
>