VCA chips

[jhaible]

> I phoned Analog Devices.  They said, as I suspected, that the SSM2024
> is still in production but the SSM2164 is recommended for new VCA
> designs.  And they left the SSM2024 off their web site because they
> are not recommending it for new VCA designs.

Yes, that's more or less the same answer I got.
Isn't it sad - if they hush up the chip, it is going to die sooner or later
..

> Hmmmm....  The data sheet says it'll take an Iabc of 10mA without
> exploding, but no curve is plotted for more than 1mA in the data
> sheet.  It makes me a little suspicious.  It's certainly an area to
> explore.

I think the Prophet 5 uses them with rather high control currents. I
remember
thinking these low resistor values were typos, until I saw that the 3280
allows
that high control currents. But the Prophet 5 might not be the best
reference
for the ultimate analogue design (with all repect to its brilliant
concept).

2 questions left:

What do you think about high control currents for discrete transistor pairs
?
Any drawbacks ? Do the transistor pairs unbalance themselves due to self
heating at higher currents ?

Availabillity of the CA3280 - I know it's hard to get in Germany. But is it
still manufactured or not ? I have a few left, but I hesitate to use them
if
I can't get them in the future ...

JH.