midi-cv adapters

[Grant Richter]

Without re-opening the thermionic vs. solid state issue.

Aside from the engineering challenge of building
an all tube device, which is very admirable.
It seems that the audio range is where a tube
produces the most pleasing effect.

So if the audio chain of the device were all tube,
would the public accept it if the associated DC
processors (exponential converter, DC amplifiers)
were solid state?

To use a solid state example. Replacing a uA726
exponential converter with a LM394 and Q81 will
have no affect on the "sound" of the VCO since
the exponential converter is not in the audio path.

It would be challenging, but not difficult to build
discrete solid state op-amps the will function with
+/-100 volt supply rails and interface much more easily with
tube voltage ranges. This would provide many
advantages for DC and control voltage processing,
without disturbing the all tube nature of the audio
path (VCO-VCF-VCA).

I highly recommend "Electronic Analog and Hybrid Computers"
by Granino and Theresa Korn from 1964. It was written just
at the conversion from thermionic to solid state and presents
most circuitry examples in both forms. BTW the conversion to
solid state also move the standard analog computing voltages
from +/- 100 volts to the +/-10 volt standard in use by ARP,
Aries and others.

----------
> From: Eric <svetengr at earthlink.net>
> To: synth-diy at mailhost.bpa.nl
> Subject: midi-cv adapters
> Date: Sunday, February 13, 2000 3:05 AM
> 
> Question for anyone with experience with
> Kenton or Rees midi-CV converters:
> 
> After much work, I finally made a thyratron VCO
> track reasonably well over about 2 octaves
> in v/Hz fashion. It works great with the Philip
> Rees midi-CV, but the Kenton Pro Solo does not
> have a broad enough CV range in the lower
> octaves. And it is too difficult to change the
> gain
> of the thyratron driver-it's already at the
> bleeding edge.
> 
> Anyone have experience with using Kentons
> and had such a problem, esp. in v/Hz?
> If this can be resolved, the result will be
> at least 2 new Meta products. (Including a
> replacement for the "Phattytron" at a much
> lower price.)
> 
> 
> 
>