SSM2038 Schems?

[Iain Dunn]

Scott Bernardi wrote:
> 
> The Synthesis Technology sight has the SSM2013 (VCA), SSM2014 (VC Element),
> SSM2015 (mic preamp), SSM2120/22 (dual VCA), SSM2044 (4 pole VCF), and
> SSM2045/2047 Voice (Filter + VCA) datasheets. No SSM2038. They also do not
> have any of the SSM chips on their pricelist.
> 
> There seems to be a real dearth of VCO chips of any type. The only place
> I've seen advertise availability of ANY kind of VCO chips is the CEM3374
> dual VCO on Synthesis Technology's page ($15). A dual VCO sounds great, but
> to temperature compensation is not complete on the chip. It provides a
> reference voltage that you have to multiply the control voltage by (which
> is what we do with a tempco resistor). You can do this under digital
> control with a multiplying DAC, or using analog multipliers (one for each
> VCO).
> 
> I sent an email last week to DB Musical electronics, which advertises that
> they carry SSM and CEM chips, asking about what they actually have in
> stock, so I could share it with synth-diy. Haven't gotten a reply yet.
> (They did quote me $30 for a CEM3340 VCO a couple of weeks ago. Pretty
> steep, but I guess that's supply and demand).
> 
> And speaking of sources, where do you guys get things? For example, I've
> seen Farnell mentioned as a source of the Q81 resistor on more than one
> message, yet I sure can't find it when I search on their web site.
> What about matched pnp's - AD821, MAT-03, etc? Has anybody looked at the
> MPQ2907 (quad 2N2907 pnp's)? They're probably not monolithic, but are they
> matched enough to make a decent current mirror (to mirror a matched npn
> exponential current sink into sources for OTA's).
> 
> Full of questions. Seems to be the biggest hurdle to someone doing a DIY
> synth these days is getting the necessary parts (I built one in the early
> 80's, and stuff was plentiful back then. I'm coming back after a 16 year
> absence).
> 
> At 07:31 PM 5/7/98 +0200, you wrote:
> >
> >-----Original Message-----
> >From: Yoshiki Ohmura (Yoshi) <yoh212 at lulu.acns.nwu.edu>
> >To: synth-diy at mailhost.bpa.nl <synth-diy at mailhost.bpa.nl>
> >Date: Thursday, May 07, 1998 7:45 AM
> >Subject: SSM2038 Schems?
> >
> >
> >try this: http://www.synthtech.com/cem/cemdata.html
> >
> >>I just got a few of the SSM2038 VCO's with an order of chips, and I was
> >>wondering if anybody had some schematics for these chips.  I really don't
> >>know anything abou them, there seems to be no lit. on those chips.
> >>
> >>Thanks
> >>
> >>Yoshi
> >>
> >>
> >
> >
> >
> --------------------------------------
> Scott Bernardi
> voice: 415-538-0439 (note new number)
> fax:   415-904-8375
> scott.bernardi at fritz.com
Re Q81 Tempcos-

Farnell no longer stock these excellent tempcos but I recently obtained
20 directly from the manufacturers VTM in Amersham UK. They advised me
that there is no problem with supply on these as they are used in air
conditioning, fridges , electronic ignition systems.

One thing to be aware of though is that they are NEGATIVE 3000 PPM- not
a problem just a minor circuit alteration.

I use these in my MINI clone along with SSM2210 matched pair transducers
and the tuning is rock steady (far better than any heated circuit
including the Doepfer).

The SSM2210 is available from Maplin and Farnell.


regards

Iain