[sdiy] Buchla VCOs

[ASSI]

On Sunday 08 June 2003 22:11, Grant Richter wrote:
> In the Buchla gestalt, a keyboard is a "Kinesthetic Input Port" and
> specifying pitch is only a small part of it's duties. The Model 219
> you have is the most advanced of the designs, it has 38 voltage and
> pulse outputs, only 4 of which concern pitch (4 voice scanning
> polyphonic).

Fascinating, where could I read more about these?

> I would expect MOTM or Wiard
> modules to have a 100 year lifespan or better due to the high quality
> of modern process controls. Modern semiconductors can have a 1
> million hour MTBF, which is 114 years.

The typical specification for an IC nowadays is a FIT (failure in time) 
rate, typically in the hundreds to single digit ppm range, accompanied 
by an operating conditions lifetime profile (15a at 85°C + 1500h at 115°C or 
some such). The qualification tests are made on a few hundred samples 
at accelerated conditions and are typically designed so that none of 
the samples must fail the test (a few hundred hours). Testing for MTBF 
in the range that results is simply not possible, as you need to fail a 
good portion or even all of the samples to get reliable statistics. 
Test-to-fail is used for qualification of individual devices and 
metallization, where higher acceleration factors can be used.


Achim.
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