In Tom's defense. :)

[Tony Clark]

> Well, I suppose he got some of us a bit suspicious by hyping his 
> circuits a bit 
> too much. Like saying "WOW it's nice" about the sinewave output on the Maxx 
> VCO-4A. The sinewave converter employed is the same as in the Formant. It is 
> widely known that this circuit give a fairly crude approximation if a sine 
> wave. Several better circuits exist.

   It's no wonder that Tom was frustrated.  He's obviously not getting 
much praise from this person!  The main problem is that there are people 
that are wanting too much perfection out of the circuits they build.  
Hey, I'm one of those people!  But I do realize that there was a reason 
circuits like Tom's exist.
   It is because "better" circuits are typically 2 to 3 times harder to 
build!  I build a very good tri-sine converter, but it has a great deal 
more circuitry than "crude" approximators.  Will mine sound better?  
Probably not.  That is why if you go back and take a look at MANY of the 
Moog, Arp, Korg, etc. schematics, you will find many "cheap" circuits.

> Also that he omits temperature compensation without mentioning it 
> (like in the VCF-5A) raises some skepticism.

   Why?  There are many on this list that are running ASM-1 VCO's without 
temperature compensation _and they run fine_.  You don't have to 
temperature compensate "everything".

> There also are some bad design practices, like 
> in the BRM-1A where pin 13 on the CA3046 is not at the lowest 
> potential, which the National Semiconductor datasheet points out is 
> important for proper operation.

   Some of the best advances in circuit design is using stuff in ways 
they weren't meant to be used.  A case in point, using that CMOS chip for 
8 matched MOSFETs by not tying the Vee (or some such thing).  Whoever 
came up with that trick is a genious in my book.

> I don't doubt that he has actually bulit the circuits and that they 
> do work, but things like that raise questions.
> I think if he had said up front that these are simple circuits suitable for 
> beginners and less critical applications, but have some limitations, he would 
> have got more understanding and support.

   I think it is clear that there was obviously too much expectation on 
the part of certain individuals for mind blowing advances in circuit 
design.
   The best part about the DIY list is that we can have a wide range of 
expertise in the field of electronics, but also have a large membership 
of people who really don't know much about electronics whatsoever.  I'm 
sure had Tom gone through and given all of the theoretical data for his 
circuits prior to putting circuits up on his site, it would have 
eliminated the need for certain individuals to fuss. 
   However if anyone on this list has any knowledge of engineering worth 
a salt, his circuits should be fairly easy to deconstruct.
   Anyway, I certainly appreciate the amount of time and work Tom has put 
into his site.  Keep it up, Tom!  And don't ever let any non-believers 
get you down!

   Tony

P.S.  Always ask "WHY" it works, not "DOES" it work.

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I can't drive (my Moog) 55!         |     The E-Music DIY Archive
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Tony Clark -- clark at andrews.edu     | aupe.phys.andrews.edu/diy_archive
http://aupe.phys.andrews.edu/~clark |     Contributions welcomed!
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