[sdiy] Thoughts on VCO's

[Richard Wentk]

On 2 Mar 2009, at 21:38, David Ingebretsen wrote:

> I've got a few questions regarding VCOs. While a critical part of any
> synthesizer, are there really a lot of differences?

Yes. Filters are over-rated. Oscillators are under-rated.

> Here are a few personal preference questions:

These really come down to clinical vs musical applications. The  
problem with clinical VCOs is that while randomness *can* be added,  
it usually isn't.

Let's say you have three very accurate VCOs. You want to add some  
random movement to them.

To do a good simulation of analog splurge, you're going to need to  
use three independent noise sources, with independent smoothing and  
filtering.

Most people either won't have those modules, or won't bother.

So - imperfect is definitely better. If you want clinical  
oscillators, you can always build them digitally, and make them do a  
lot more besides. They won't be cheap, but then neither are some of  
the commercial VCOs.

At the limit, the old Moog 901 is probably the poster child for  
crappiness from a design POV - incredibly poor tracking and  
temperature stability - but nothing else sounds quite like it.

It's a nice simple, cheap circuit too.

Richard