Wasp thoughts

[Haible Juergen]

	>JH> Short question: Could anybody who owns an EDP Wasp could
check
	>if the CMOS IC that is used for analogue amplifiers is buffered
or
	>unbuffered type? 
	>Hi folks, the Clef Bandbox used UB chips for its drum sounds. B
chips
	>do not work for most analogue situations. I know because I've
tried it.
	[...]
	>Tony Allgood

This makes complete sense. I just wanted to be sure, because
the schemos just say "4069". And my main source of electronic
components (Reichelt Electronic) only lists one type. And now
I think the 4069 is probably *always* an UB type. (Checked
the Motorola and Philips Data books.)

Some general Wasp thoughts:

I just happened to hear the Wasp track on Matthias' Becker's
"Synthesizer von Gestern" CD, and I was astonished how
good this Wasp is sounding. As usual, this does not tempt
me to buy one, but to dig out the schematics and look how it's
done, and if I can build part of it as a standalone module.
As I went thru the circuit during the last days, I was surprised
more than once what an increadibly clever design this is.
Until then, I thougt it was little more than a toy, and the only
design goal would have been cutting cost (which surely *was*
an important goal). But look at the filter: The core of a 
State Variable Filter ("SEM type filter") is built around
two and a halve ICs: two 3080s, plus three of the six inverters
of a digital 4069 chip. And while these surely *are* cheap
opamp replacements, they also *do* have their benefits.
(Slew rate, bandwidth, and a nice nonlinearity)
And they have the best performance at 5V supply - so the whole
Wasp (except the power amp) runs on 5V - good for battery
operation. And look at the power supply decoupling for the
555's in the VCOs. The designer thought of *everything*.
Or take the LFO, also built around a 4069 chip, and look at
that S&H circuit that can directly interface with a digital
noise source, without a smoothing filter in between. Increadible.

I think the filter will be a first candidate for building a little
stand alone module.

JH.

PS.: Does anybody have any idea why the "good" envelope is routed
to the VCA, while the simple one controls the filter ?? That's
a choice I do *not* understand. I can live with AR on the VCA,
but the VCF should have more than AD, shouldn't it ??