Two more Analog Shift Registers are in service!
2004-07-05 by Richard Brewster
This weekend I completed the first of two "all-jack" CGS combination
panels. Each Front Panel Express panel is in 2U MOTM format and
contains 32 jacks. The first contains two CGS34 Analog Shift Registers,
plus the CGS26 Analog Logic board. Those take up 20 jacks. The other
12 jacks are used as three 4-jack multiples that can be normalled
together. Behind the scenes, five Stooge brackets support the three boards.
All modules worked perfectly on power-up. Thanks to recent discussions
on this list, I believe I came up with a good parts selection. I used
.1uf polypropylene caps, Mouser 505-MKP20.1/250/5 (Wima) for Cx, and
added a 100 ohm resistor from pin 14 of the TL074 to pin 3 of the first
4052, as mentioned in Ken's notes. There is a long trace that is easy
to cut and solder the resistor inline on the bottom of the board. Ken
says this is not needed, and it seems to me that driving the capacitor
directly from the output of the op amp (throught the 4052, of course)
presents no problem, as long as the signal is steady, or low frequency.
But as the frequency increases, the impedance will decrease (capacitive
reactance is inversely proportional to frequency). It seemed to be a
good idea to add the resistor, since who knows what sort of signal I
might patch to the input.
I have a patch up that uses the two ASRs to drive six VCOs. This
typifies the way I intend to use them, which is to multiply the two CVs
I can get from my Blacet Miniwaves, running in quantizer mode, to get
six 1V/oct quantized voltages.
The next "all-jack" module will be a digital unit that combines a pared
down CGS13 Gated Comparator (just the shifter function with 8 outputs,
clock and data input), a pared down CGS36 Pulse Divider (just the
divider), and a CGS39 Quad Logic Gate (NOR). Since there are 20 digital
outputs on this panel, I am also adding five CGS56 Gate Converters. It
could get a bit cramped for space, but I'm counting on Stooge brackets
to come to the rescue!
-Richard Brewster
panels. Each Front Panel Express panel is in 2U MOTM format and
contains 32 jacks. The first contains two CGS34 Analog Shift Registers,
plus the CGS26 Analog Logic board. Those take up 20 jacks. The other
12 jacks are used as three 4-jack multiples that can be normalled
together. Behind the scenes, five Stooge brackets support the three boards.
All modules worked perfectly on power-up. Thanks to recent discussions
on this list, I believe I came up with a good parts selection. I used
.1uf polypropylene caps, Mouser 505-MKP20.1/250/5 (Wima) for Cx, and
added a 100 ohm resistor from pin 14 of the TL074 to pin 3 of the first
4052, as mentioned in Ken's notes. There is a long trace that is easy
to cut and solder the resistor inline on the bottom of the board. Ken
says this is not needed, and it seems to me that driving the capacitor
directly from the output of the op amp (throught the 4052, of course)
presents no problem, as long as the signal is steady, or low frequency.
But as the frequency increases, the impedance will decrease (capacitive
reactance is inversely proportional to frequency). It seemed to be a
good idea to add the resistor, since who knows what sort of signal I
might patch to the input.
I have a patch up that uses the two ASRs to drive six VCOs. This
typifies the way I intend to use them, which is to multiply the two CVs
I can get from my Blacet Miniwaves, running in quantizer mode, to get
six 1V/oct quantized voltages.
The next "all-jack" module will be a digital unit that combines a pared
down CGS13 Gated Comparator (just the shifter function with 8 outputs,
clock and data input), a pared down CGS36 Pulse Divider (just the
divider), and a CGS39 Quad Logic Gate (NOR). Since there are 20 digital
outputs on this panel, I am also adding five CGS56 Gate Converters. It
could get a bit cramped for space, but I'm counting on Stooge brackets
to come to the rescue!
-Richard Brewster