[sdiy] vco's

[Dave Magnuson]

>> From: synth-diy-bounces at dropmix.xs4all.nl 
>> [mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of Dave Magnuson
>> Sent: Tuesday, April 07, 2009 2:29 PM
>> To: synth-diy at dropmix.xs4all.nl; Ian Fritz
>> Subject: Re: [sdiy] vco's

SNIP

>>
>> The difference is pretty subtle - more "buzzy-ness" on the saw, etc... 
>> which
>> I assume is a difference in harmonic content.    For reference, I have a
>> 3340VCO and a trio of EFM VCO4D (which was a Moog Sonic Six clone, IIRC)
>>
>> Dave


----- Original Message ----- 
From: "Scott" <Scott at scottwick.com>
To: <synth-diy at dropmix.xs4all.nl>
Sent: Tuesday, April 07, 2009 3:59 PM
Subject: RE: [sdiy] vco's


> And, sorry, Im not saying you definitely can see the difference in yours, 
> or that your vco has a flaw.
> The glitch in my vco is very small, and makes a large difference in the 
> harmonics.  So, I can see where subtle differences on the edges of the 
> waveforms can make a difference.
>


Hi Scott,

I have no doubt that the EFM VCO outputs are "flawed" (Harry B. could chime 
in here... I think he's modified his quite heavily).    I know the tri and 
sine are a bit funky, but the saw is pretty accurate IIRC.   Been a long 
time since I've looked on the 'scope however.    The pulse is also a bit 
"round" without the addition of a pull-up resistor that wasn't included in 
the original design.

When I make samples I will use saw waves, since it's the most accurate 
looking wave.   I suspect you're right that it's the wave edges (and their 
related harmonics) that are making the difference that I hear.

Dave