Yahoo Groups archive

MOTM

Index last updated: 2026-04-28 23:35 UTC

Message

Re: More VCA blabbering

1999-10-29 by J. Larry Hendry

> From: "Dave Bradley" <daveb@...>
> 
> You are confused, my son. Unfortunately, I must explain using a few
> engineering terms.
> 
> MOTM-110 input is linear, not exp. Its transfer function (graph of output
> over input) is a straight line. Therefore, if you input a linear voltage,
> you get a linear change out. If you input an exponential voltage, you get
an
> exponential change out. Your ear wants an exponential response, which the
> linear VCA input passes unchanged from the 800s exponential output.

Actually, this is the part I understand clearly as Paul has spelled it out
that the CV is expo and VCA is linear in the MOTM docs.  My mistake was
calling the MOTM-110 input expo since it is an expo voltage applied at that
point for proper operation.  I now see the error of my ways and that I
should call that input linear.

> Neinsky, comrade. Linear input responding to expo voltage is already the
> status quo when you hook an 800 to a 110. An input doesn't "expect"
> anything, it just responds to what is fed into it, as determined by the
> transfer function mentioned above.

By expects, I meant for the "status quo" or normal operation.  Who is
Neinsky anyhow?  Didn't he used to play for the GB Packers.  :)


> The EG has its own transfer function
> also - if you graph the voltage change over time from point A to point B,
> you get an exponential transfer function. If the VCA has an input that
also
> has an exponential transfer function, these two functions are multiplied
to
> achieve the overall transfer function that describes the total output
over
> input, which is this case is output gain over time.

Very well explained Moe.  So my original question should have been "why
would one want an "exponential" input on a VCA.  And, the correct answer is
quadratic transfer function for "whompass" attack.
:)
Larry (extra stoogy today) Hendry

Attachments

Move to quarantaine

This moves the raw source file on disk only. The archive index is not changed automatically, so you still need to run a manual refresh afterward.