Noise reduction for NE571

[The Dark force of dance]

Y-ellow Paul.

At 12:14 AM 07/28/99 +1000, Paul Perry wrote:
>At 10:44 PM 27/07/99 +0900, The Dark force of dance" <batzman wrote:
>
>>with a rectifier placed in front of it. You cannot control the attack and
>>decay of the control because there is only one node upon which to place a
>>cap. Unlike the 572 which has two nodes and you can even make the
>>attack/decay times variable.
>>
>can anything be done with steering diodes?

Yeah I tried that without success. I ended up with quite an elaborate
scheme. Even had an op-amp in it but it was of no practical value. I ended
up making a rectifier out of a couple of op-amps and integrating it across
a cap myself. That way I could put the diodes in the control path as
opposed at the bottom of the rectifier. From there it was only a hop step
and jump to using an OTA instead of the one built into the 571 and the
whole thing was redundant. Believe me a 3080 is a whole lot quieter than
the 571.

It has to be born in mind that the 571 was originally designed in the 1970s
for use in telephone voice traffic. The 572 was a vast improvement but they
must have taken at least 12 or 15 years to get round to designing it.  The
572 is dead quiet by comparison. But then again it costs 3 times as much
and the 571s were already quite expensive.

You're better off using an  OTA and a 324 with some diodes and stuff if you
wanna get serious. It'll cost about the same but you get to do what you
want with it. I'm use to them now but even the 572s are still a bitch to
use. They do some pretty unpredictable things and the data sheet is pretty
awful. Just like an Analog Devices data sheet. 

Be absolutely Icebox.

 _ __        _                              
| "_ \      | |         batzman at all-electric.com / aek at all-electric.com
| |_)/  __ _| |_ ____           ALL ELECTRIC KITCHEN               
|  _ \ / _` | __|___ |  The Elementary Urban sanity CD
| |_) | (_| | |_  / /   out now on Transmission Communications
|_,__/ \__,_|\__|/ /    
                / ,__   http://www.all-electric.com
Goodfortune    |_____|