Enough already Peter. I submit. Okay... when can I buy a couple Seriously, I'm sold.

Regards,
Kevin


--- In Doepfer_a100@yahoogroups.com , "(i think you can figure that out)" <peter@b...>
wrote:

> Oddly enough, the saw waveshaper in this cicuit is my design
> and about the only part that I'm really proud of as it uses only two
> componets, tracks wonderfully across the whole frequency
> range and sounds great (this is what you're hearing with the high
> end fizziness you mentioned).
>
> As far as the improvements, most of what I did was replace all of
> the 258's wacky discrete components with ICs and modern day
> equivelents. Buchla used an FET for the initial amplification, I
> used a TLO Op amp. He had a discrete comparator made from
> a series of NPNs, I used an LM311. Most significant however is
> that ALL of the semiconductors in the core circuit in the original
> 258 are obsolete now and it will cost you about $125 for these
> parts alone if you set off to make one in the 21st century. I
> replaced all of these with modern day equivelents and in so
> doing, dropped the cost significantly and decreased the
> matching from 5 mv to .3mv (this is a good thing btw as it effects
> the drift).
>
> Luckily, these subs did not change the sound at all. You see, I
> was building a 258 kit for somebody when I designed this circuit
> and had one here for a sonic reference.
>
> As far as the other additions, I just looked the circuit over added
> things that Buchla omitted originally. For instance, he didn't have
> a sync input (VERY easy to add). While he had square out, he
> didn't have PWM. Without going into details, the way Don made
> the square waves would not allow for PWM. I used the traditional
> method off the triangle core and was amazed at the sound. Don
> also didn't elect to bring the triangle waveform to the faceplate.
> Given that this is a triangle core VCO, it's VERY easy to do that,
> so I did.
>
> Another thing - in that all of my waveshapers are first generation
> (all using the triangle as a source), I was able to include a
> waveshape crossfader (which I call morphing) because all of the
> waveshapes are in phase with one another. Now, I'll admit this
> part doesn't sound like the Buchla method, which sort of 'grew'
> either a ramp of square out of the sine waveshaper circuit, but I
> am happy with my results. As a point of ference, I used vactrols
> in my crossfader which really smoothes the cross fading out,
> much more so if it was done soley with op amps.
>
> What I tried to do was make a VCO that behaved like a 258 in it's
> reaction to FM (AC) and frequency response to linear VC (DC).
> That part I was able to nail down accurately. I wasn't concerned
> if the other parts sounded different, because both being triangle
> core I knew they wouldn't be THAT different and they aren't
>
> - Peter