[A6] A6 sine osc

[Shawn O.]

 >So, is this the standard A6 version of a sine wave, or is it just mine 
that's a bit bent?


I have 2 Andromeda's now and checked this out on both of them, same 
thing, this is at really low frequencies that this occurs,. happens with 
triangle and square waves as well, correct me if I am wrong I believe 
this is actually how the moog modular VCO of the time performed with its 
older component discrete construction,

I would guess modules from Modcan and MOTM have much better tracking 
with producing sine waves that are pure at low frequency levels, both of 
those companies seem to be into producing analogue perfection.

One thing that makes me scratch my head is how the same FM patch on two 
different Andromeda's does not sound the same at all, well even between 
different voice chips when you are cycling through on patches that use 
allot of FM,

also of note, so far 2 out of 3 Andromeda's that I have had my hands on 
display an interesting amplification of white noise on at least 1 of the 
voices playing the patch Amsterdam kick patch in rotary mode (think this 
is preset1 81), on some voices the amplification of white noise is 
subtle, on others it is very noticeable, my work around for this is 
saving that patch to the user bank and turning the white noise off or 
assigning it to play on a voice that the noise is not noticeable.

I think this is a problem with the way the ASIC's are manufactured where 
something gets screwy in the VCA portion of the chip during lithography, 
kind of makes me wounder how much better of an instrument this would be 
if the voice chips were larger or had 1 voice on each instead of 2.

~Shawn O'Brien

Kim Johnsson wrote:

> Hi!
>
> I'm not particularly knowledgeable in analog circuitry, and I don't 
> have that much experience with real analog synths, so that may explain 
> my question...
>
> I understand that basically analog synths don't produce 
> "mathematically perfect" waveforms, and that's just the way it is. 
> Different synths' "versions" of each waveform may also differ, and I 
> guess this would be true for different manufacturers as well as 
> different units of the same synth model.
>
> Well, I just noticed that the sine wave of my A6 doesn't really sound 
> like a pure sine wave (and I can lo-pass filter it, and the sound 
> changes), so I recorded it in Sonar at a low frequency, and it looks 
> like this: http://www.kolumbus.fi/kim.johnsson/temp/a6sine.jpg
>
> So, is this the standard A6 version of a sine wave, or is it just mine 
> that's a bit bent? And out of curiosity, if I would want an analog 
> synth for the sole purpose of creating a nice sine wave (with it's 
> oscillator), which synth should I get? Which synth is The Ultimate 
> Sine Machine?
>
> Oh, if I make the A6 LP filter self-oscillate, I get a *really* nice 
> sine wave...
>
> Just a bit curious,
>
>     Kim
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