[sdiy] Discrete OTA

[Roman Sowa]

hi,

> finished my PhD, but working under the enormous pressure in a
> high-tech lab environment has resulted in a severe burn-out. I'm

you will miss that unrestricted access to a high-tech lab when you move 
away to your own small business. Maybe not today, not in 2 years time, 
but eventually you'll start to see the good points.

> That's why I'd like to figure out some way of protecting the IP. Any
> thoughts on that? I see many companies currently doing the "open
> hardware" licensing thing.... Would that provide enough protection

no way of protecting anything. Neil has already spelled out the options. 
You can only try to use the highest technology affordable to you, and 
most advanced designs, to be one step ahead. When someone copies that 
(which is not that simple anyway for average project-thief while only 
big companies have stuff like microslicer, electron microscope and 
nanoprobes), then move to something different. Either new version of the 
product, add some extra feature or move to completely new area of interest.
When I get kicked out from MIDI business by Chinese company my current 
plan is to move to woodworking/furniture business...
Notice I didn't say "if" but "when"

> scientific skills. My goals were roughly to develop a discrete OTA
> that can be made moderately cheap. I have not been aiming to beat
> high quality alternatives (2164, THAT-chips, etc), but was rather
> aiming for an alternative with a bit of character (think of the way

that's my goal too. What if our designs suddenly become very similar? 
Will there be a law suit? After all there is not much you can reinvent 
in an OTA.
Character is good, but only next generations will decide if it's 
interesting or not. We have no powers to decide about that. Have you 
ever wondered why Hammond, Rhodes, or even grand piano are considered 
classics, or the best sounding instruments of all times? They were 
designed with loads of "character" as we would say today, but only 
because technology didn't alow for anything more perfect, or should I 
say "good enough". I'd like to live the times where the most wanted 
sound will be combo organ, 8-bit sampler and aliased wavetable 
synthesis. OTOH haven't that already relived some time ago?


> temperature stability it probably needs potting too. If I had to
> estimate a price, it would probably be around 5 or 6 euro's, possibly
> a bit cheaper in larger quantities. Is this still feasible for the
> DIY community?

unless it is THE character some wants, the price is too high. One can 
always choose cheaper other OTA ICs. When the character will become 
classic, you can charge 40EUR

> 3) I could turn the prototype into 'ready made' or DIY-kit Eurorack
> modules, VCA, VCF. I already have some other innovations for a VCF on
> the bench too, so that would be included.

there are about 150 makers of eurorack modules, go dive in, there's 
enough market for everybody! I mean it, I love to see new modules 
apearing almost every day.

> ps. Any experience with companies that do potting (with
> heat-conducting epoxy)? Or can this be done cleverly DIY, yet still
> for high quantities?

potting is dissed here, so watch out ;)

Roman