[sdiy] SSM2164 Phaser - another way?

[Donald Tillman]

On Feb 18, 2014, at 10:14 AM, Tom Wiltshire <tom at electricdruid.net> wrote:

> On 18 Feb 2014, at 17:26, Donald Tillman <don at till.com> wrote:
>> 1. I think this circuit will work, it just won't work well, as the range will be limited and it will clip weirdly.
> 
> Interesting, do go on...

The 30K resistor in series with the 2164 input will limit the tuning range.  If the signal amplitude at the 2164 input goes over the roughly 52mV range of the input diff stage then it the tuning will dynamically distort.

> 
>> 2. Where did this circuit come from?  Any background on it?  The Electric Druid image suggests it's been simulated.  And "It looks ok in the sim" suggests that it works.  What does "ok in the sim" mean exactly?
> 
> I drew it. It occurred to me, so I drew it in LTSpice. "Ok in the sim" means it at least makes a notch like it's supposed to. However, the notch doesn't move like it's supposed to.

What frequency is the notch at?

>> 5. Tom, that Spice "model" is way too abstracted and simplified to work in this application.
> 
> Yes, that's what I'm discovering! Still, what's amazing is how much it will do, not what it won't.

Do you mean the notch?  That'll be there without the 2164's.

  -- Don

--
Don Tillman
Palo Alto, California
don at till.com
http://www.till.com
650 888-9632