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Bitrex Bitrex is offline
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Default I'm available for projects

Jim Thompson
Wrote in message:
On Thu, 12 May 2016 17:12:48 -0400 (EDT), bitrex
wrote:

Jim Thompson
Wrote in message:
I sit here bored out of my skull with nothing to do but play Solitaire
until the next project start on July 5 ;-)

I'm noted for custom Analog/Mixed-Signal Design and Spice Behavioral
Modeling, but I also do designs using off-the-shelf components.

No project is too small... I've even done one-day designs from
time-to-time.

Drop me an E-mail (*)

(*) Do not include attachments in your first E-mail... An E-mail not
matching an entry in my addressbook and with an attachment drops your
E-mail into a black hole.

...Jim Thompson


In the mid 1980s, Roland had International Rectifier design a
custom chip called the IR3R05 for their analog synthesisers. I
think it was a 14 pin package...it basically consisted of 4 OTA
stages like the Lm13700 configured as a 24 db/octave resonant low
pass filter with inputs for voltage controlled frequency and
resonance, along with a VCA with both linear and exponential
inputs, all on the chip. The 4 filter capacitors were mounted off
chip on the board.

What kind of job would it be to design a chip or maybe a
daughterboard that performed an equivalent function? These chips
often fail in vintage equipment and there seems to be a decent
sized market for replacements that dont require scrounging for
NOS or cannibalizing old units.


I'm sure I could replicate the chip, but I don't do PCB layout, that's
another skillset altogether.

...Jim Thompson


Good thing I've got that skillset. ; )

I wonder it the required components could be squeezed into a
daughterboard that would fit the space available. Might require
some vertical mounting hack.

--


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