[sdiy] SSM2164 VCA

[Stewart Pye]

Good point about the noise Neil. The LM431 and a few resistors would do 
for this and it's less than 20 cents.

Cheers,
Stewart.

Neil Johnson wrote:
> Hi,
>
>> All the designs I've seen based on the Mike Irwin design change Vref 
>> to whatever they want the CV range to be. Is there a reason why you 
>> couldn't just use -15V and scale the resistor connected to Vref to 
>> suit? Wouldn't the 2164 just be seeing a current input, and not care 
>> what voltage is on the other end of the resistor?
>
> A couple of quick observations:
>
> 1/ What happens if my "+15V" is not actually +15V, but perhaps +14V?  
> Or is someone wants to run your module from +12V?
>
> 2/ Any noise on the rails (and they are generally noisy, shared across 
> all modules) will couple very easily into your signal path.  Unless 
> you consider this desirable I'd say save up your pocket money and 
> splash out on, at the very least, a 5v1 zener or even better a proper 
> voltage reference diode.
>
> Neil
> -- 
> http://www.njohnson.co.uk
>
>
>
>