CA 3019, MC 796 thanks!

[jorgen.bergfors at idg.se]

Thank you all for the information. Some of you assumed that I'm thinking of 
building the sequencer. Well, right now I'm mainly interested in the 921B VCO. 
Have any of you built it? Is it worth building or are there better sounding / 
more stable / easier to build alternatives that you would prefer?
Yesterday evening (late...) I built the saw to triangle circuit from the 921B. 
It worked, but there is a small glitch at the top of the triangle and the 
triangle waveform is not quite symmetric. This is not suprising as I'm running 
it on +-15V instead of +12 and -6 volts. I suppose I can fix this by changing 
some resistors. I'll try that tonight.
By the way, this circuit is a bit unusual as it uses only two trannies and no 
diodes or op-amps.
I intend to use it for my Doepfer PMS VCO, which has only saw and pulse waves. 
I'm going to try the triangle to sine converter from the 921B too.

/Jorgen





MIME:gjalass at berlin.snafu.de on 98-04-17 23.57.08
To: Jorgen Bergfors at IDGSE
cc: synth-diy at mailhost.bpa.nl @ SMTP  
Subject: Re: CA 3019, MC 796?

On Fri, 17 Apr 1998 13:24:41 +0100, you wrote:

>I looked through the schematics for the Moog modular, and found a couple of
ICs 
>that I haven't seen before. Anyone know if they are available or if there are

>equivalents/replacements?
>
>CA3019: contains six diodes.

To my knowledge is no equivalent available. Nevertheless - You might
want use a different design for the clock (Sequencer 960) or build
oscillators of the better type ( 920/921 ).

>
>MC 719, 778, 793, 796. These are logic chips. TTL, DTL, RTL? Probably some 
>precursor to the 74xx series. Are there 74xx equivalents?
>
>Jorgen Bergfors
>

All this MC-stuff ( being used in the sequencer and its support -
960, 961 and 962 ) is definitely not TTL ( a lot of open collector
type of logic ). It must be an ancient type of IC's ( a supply voltage
of 3.6 V ! ).

NB, the 796 used in the 921B design is looking like a LM/MC 1496 in a
TO case ( when comparing the pin number of the circuit, their use in
the circuit itself and the 1496 datasheet ).

Hope this doesn't disappoint too much.

Gert