[sdiy] returning to the chronic disappointment of the 1496...

[karl dalen]

Well, its relative, all remaining analog shit are outrageously expensive
compared to yesterday. Soon it's cheaper to replace an OTA/BalMod with a
32 bit MCU and do a simple MUL operation!

The market elephants are trying to force the analog engineer to think
HF analog! Radio, thats coll stuff, buy our latest 1Ghz AD converter
for only 99.99! :( 

THAT and some few others sees a opportunity and greedily explores it.

KD

--- Den fre 2010-01-15 skrev Tom Farrand <mbedtom at gmail.com>:

> Från: Tom Farrand <mbedtom at gmail.com>
> Ämne: Re: [sdiy] returning to the chronic disappointment of the 1496...
> Till: alfred.pear at gmail.com
> Kopia: synth-diy at dropmix.xs4all.nl
> Datum: fredag 15 januari 2010 05.11
> An AD633 is "prohibitively expensive"
> at $7?  No, a Z-80A I paid $200
> for was "prohibitively expensive" when I was making <
> $8/hour!
> 
> Peace.
> Tom Farrand
> 
> 
> On Thu, Jan 14, 2010 at 12:36 PM, <alfred.pear at gmail.com>
> wrote:
> >
> > Alright, apparently I was premature in denying the
> existence of AD633
> > in an otherwise chaotic and indifferent universe.
> >
> > However, the $7 IC is prohibitively expensive when
> compared to the
> > lure of a 50 cent LM1496.
> >
> > Jurgen, the doubled carrier frequency is the exact
> problem. I will
> > take a much closer look at the modulation stage in
> your Frequency
> > Shifter.
> >
> > I'm also very interested in your solution, David..
> I'll commence
> > pestering shortly.
> >
> > Thanks SDIY!
> >
> > -AP
> >
> >
> > On Thu, Jan 14, 2010 at 1:31 PM, David G. Dixon
> > <dixon at interchange.ubc.ca>
> wrote:
> > >> Has anyone found any workarounds for the
> signal bleed-through problems
> > >> with 1496s used as 4Q-Multipliers?
> > >> I've read and re-read mailing list archives,
> message boards, and tried
> > >> almost all the schematics I could find...I
> cannot seem to get the two
> > >> signals to actually *balance* with real
> precision.
> > >>
> > >> With the 633s and 1495s off the market, there
> has to be a cheap,
> > >> effective solution to ring modulation, right?
> Have OTA approaches
> > >> yielded worthwhile results?
> > >
> > > Alfred, I have developed, built and tested a 4Q
> multiplier based on the
> > > linearized SSM2164 (actually I use the Coolaudio
> V2164 -- $3.50 each at
> > > Small Bear, or $3.00 for 10 or more).  It works
> very well.  I originally
> > > developed the circuit based on the LM13700, and
> this also works very well,
> > > but is a little bit trickier to set up.  In
> either case, I arranged the VCAs
> > > in a "push-pull" arrangement.  One processes the
> carrier signal as is, and
> > > the other processes the inverted signal.  Also,
> one is controlled by the
> > > modulating signal as is, and the other is
> controlled by the inverse of the
> > > modulating signal.  In the case of 13700, the
> carrier signal must be
> > > dramatically reduced to avoid distortion, and the
> modulating signal must be
> > > shifted carefully, but things are much more
> straightforward with the
> > > linearized 2164.  I also have a pot which pans
> between the two carrier
> > > signals such that at either extreme one obtains
> 2Q multiplication, in the
> > > middle one obtains very well balanced,
> symmetrical 4Q multiplication, and in
> > > between one obtains various degrees of
> unbalanced, asymmetrical 4Q
> > > multiplication.  Finally, I've also brought both
> signals in through
> > > variable-gain ideal rectifiers fitted with 3-way
> switches which allow either
> > > +, +/-, or - polarity.  This adds a lot of
> unique functionality in CV
> > > modulation, and creates some very subtle and
> interesting effects in audio
> > > modulation.
> > >
> > > This circuit grew out of the desire to avoid
> spending beaucoup bucks on
> > > "proper" multiplier chips like the 633, and also
> from the painful
> > > realization that the (very simple) ring-mod
> circuit in the LM13700 datasheet
> > > sucks really hard!
> > >
> > > Please email me if you are interested, and I can
> send you my design files.
> > >
> > >
> >
> > _______________________________________________
> > Synth-diy mailing list
> > Synth-diy at dropmix.xs4all.nl
> > http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
> 
> _______________________________________________
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> 


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