[sdiy] CS80 Filter IC schematic

[JH.]

http://home.debitel.net/user/jhaible/cs80_vcf_spice_jh.pdf

JH.


----- Original Message ----- 
From: "Roy J. Tellason" <rtellason at blazenet.net>
To: <synth-diy at dropmix.xs4all.nl>
Sent: Monday, January 24, 2005 9:12 PM
Subject: Re: [sdiy] CS80 Filter IC schematic


> On Monday 24 January 2005 10:18 am, Antti Huovilainen wrote:
> > Hi
> >
> > Does anyone have schematic for the mystery IG00156 IC used in Yamaha
CS-80
> > filters? The chip has outputs named HP, BP, LP (and other pins) so I'm
> > guessing it is some variant of SVF.
>
> As it happens,  I do have a "datasheet" of sorts on this chip.  Says it
was
> made by Mitsubishi,  though they don't give an OEM part number.  Says it's
a
> VCF...
>
> Pinouts are as follows:
>
> 1   AI   Signal input
> 2   KV   Key voltage input
> 3   fc   Adjustment of the cut off frequency
> 4   Vf   Input of the cut off voltage
> 5   Vcc   +15V DC voltage supply
> 6   Qo   Qo adjustment
> 7   VQ   Voltage input of Qo control
> 8   GND   Ground
> 9   FB   Q feed back
> 10  LP   Low-pass output
> 11  C2   Capacitor2 (fc determination)
> 12  Vee -15V DC voltage supply
> 13  BP   Band-pass output
> 14  C1   Capacitor-1 (fc determination)
> 15  HP   Hi-pass output
> 16  FBIN   Input of feed Dack (!)
>
> From what I can see in the block diagram,  the circuit is three amplifiers
> with two "Variable gm circuits" in between,  and two other blocks labeled
> "Cutoff control" and "Q control".  There's a bit more in another diagram
> labeled "Circuit Illustration" that doesn't really show all that much...
>
> Hope this helps,  some.
>
>
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