Update and the Prologue-4

Tony Allgood oakley at enterprise.net
Sun Mar 1 18:41:09 CET 1998

Hi all,

Many thanks for your help with my tube/valve enquiry... I will keep you
posted on any developments there.

I have posted the schematics of my VCF rack to Tony Clark. They should
appear there sometime soon. PCBs could be ordered as soon as get feedback
from would be buyers.

Now a question, have any of you had any problems with a UK produced MIDI-cv
converter called the Prologue. Mine has two faults of note, one, it
occasionally latches up, ie the gate outputs go high and the CV rises on all
four of its output channels. Actually, it sounds rather groovy when it does
this but it is not supposed to. And secondly, there is a audible slew in the
output CV, so it sounds like a very fast glide. The Prologue uses 10n
sample/hold caps buffered by a LM324 op-amp for its CV outputs. Replacing
the surface mount caps with smaller ones leads to audible ripple as the MPX
clocks. Methinks I will have to replace the MPX chip, caps and op-amps.
Quality design it is not!

Anyone else use one of these things and found an easier way out??

Tony Allgood

Cumbria, UK

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