S&H

[Ingo Debus]

John Speth wrote:
> 
> Some 15 years ago I built a circuit that stored 64 voltages in 64 caps using 8 4051s for muxes and TL084s and polystyrene caps configured as S/H's.  It was driven digitally by 6 bit address and 8 bit data with a strobe signal.  When you write the data you select an output address and data value and it wrote it to a SRAM chip.  It had a counter that freely cycled through the SRAM, read each value stored and output it to a DAC, selects the addressed mux line which "loads" the cap voltage from the
> 

The cv generation in my polyphonic synth works very much the same. It
was a kit from Doepfer (long ago), the circuit was published in
"Elektronik" back then (1983).

BTW, the DAC (8 bit) is a Analog Devices AD558JN. I don't notice any
larger error in VCO pitch when it's transiting from 126 to 128. I use
the upper 7 bits for VCO semitone cv. Another lucky DAC user :-)

Ingo