Post your questions about the Claravox Centennial here

Posted: 11/21/2020 12:52:38 PM

From: Northern NJ, USA

Joined: 2/17/2012

"There have to be extra means for providing a stable supply voltage to the oscillators (which of course should be designed to drift as little as possible with supply voltage)." - Neutrodon

Yes, 3 pin regulators can be quite tight and inexpensive these days, particularly those little TO-92 ones.  I can't imagine relying on bulk (whole unit) regulation for the oscillators.  It might have just been their way of identifying several different units undergoing a variety of testing scenarios.

Posted: 11/24/2020 9:27:41 PM

From: Hillsborough, NC (USA)

Joined: 2/13/2005

Hey everyone. Cyril Lance from Moog has been following our conversation and offered these clarifications to some of the points you've raised about the diagrams. Here's Cyril's note verbatim:


"I wanted to take a moment to respond to the points that Flouderguts brought up.  For the power startup diagram, I should have simplified it so that there was only one Claravox example as the point of that diagram is to demonstrate that instruments come into full tuning with about 20 minutes for the components to come to temperature equilibrium.  Sometimes it is faster as shown in the "TDK" example but this really depends on the random start-up conditions present at the time you energize the circuits.

You are all correct:  the multiple examples of Claravox were under different power-supply configurations.  Yes, the oscillator voltages are isolated from the external power-supply through regulators, but it is still important to measure performance in both configurations to ensure there are no unintended performance issues with the power-supply itself - i.e. it doesn't introduce more noise, or interference with the oscillators, etc.

But the important take-aways from these two plots are:

(a) Claravox, like most of our other instruments, comes to it’s thermal equilibrium after about 20 minutes of warm-up (this doesn't mean you can't play it before then!) and

(b) once stable, it is extremely stable.

When developing oscillators and control circuitry, we always try a lot of different configurations, components, and values to try and get the best performance we can. These curves demonstrate a small set of these results! I hope you guys enjoy this level of design process as it's part of the fun in developing an instrument."


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