[sdiy] Discrete OTA

[David G Dixon]

> I'm sure the only reason for that is that Damian is still 
> very curious about my OTA and I haven't told him how it works... 

I've been reading this thread (and responding) with interest all week.  I
have one more comment on the original topic:

For 5 or 6 pounds ($8 to $10), that discrete OTA had better be absolutely
the most amazing thing ever, because the current industry standard, LM13700,
provides two OTAs in one package and can be had for about $0.3 in bulk, and
is available in both SMD and through-hole formats.

I think that the market for such a thing is probably microscopic.  Module
manufacturers are not going to buy it because it is too expensive, too
large, the OTA function is well covered by cheap, widely available chips and
the advantage of a discrete OTA circuit is debatable, potted circuits are a
pain, and installing potted circuits would have to be done by hand and may
thus add significantly to the manufacturering cost.

Now, a non-potted discrete circuit consisting of SMD parts on a tiny little
board with pin headers (like Intellijel's picoVCA, three of which can be
found plugged into the back of every Linix hex VCA module) might be popular,
but you wouldn't be able to get much for it.