[sdiy] SSM2044 Frequency Range

[Dan Snazelle]

I got this from the designer of the 2044:

( He was nice enough to answer ) 


 "From what you said...is the guy using a real SSM2044 ?  in which case he either has a defective 2044, or has used sub-standard (maybe leaky caps, for example) components.  I don't see why the supply voltage would matter.  In any case, a typical 2044 should far exceed the 1000:1 range.



Without more data it's hard to debug.  One critical question is - what does it do when it fails?  I.e. what is the voltage at the important nodes in the circuit?




Sent from my iPhone

> On Sep 3, 2015, at 3:35 AM, "Tim Ressel" <timr at circuitabbey.com> wrote:
> 
> Hi,
> 
> I am getting about 85mV when running at 15 volt rails.
> 
> I have tried chips I bought recently and chips bought quite a few years ago. My original 2044 filter used a chip from a long time ago and it has the same range issue.
> 
> --tr
> 
> 
>> On 9/2/2015 5:38 PM, rsdio at audiobanshee.com wrote:
>>> On Sep 2, 2015, at 5:21 PM, Tim Ressel <timr at circuitabbey.com> wrote:
>>> I just built an SSM2044 based directly on the datasheet schematic. I'm using 12 volt rails. The frequency range is less than expected. The most I get is about 130:1, and when I adjust it for 1 volt/octave the range is about 100:1. Even when I run it on 15 volt rails I get about 370:1. This is far short of the 1000:1 the datasheet talks about.
>>> 
>>> Any ideas?
>> Do you see +/-90 mV at pin 13 when you vary the CV?
>> 
>> How are you confirming the filter frequency cutoff?
>> 
>> Do you have the entire circuit on page 54, including the Frequency Offset Adjust and the Control Summer?
>> 
>> Brian
>> 
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> 
> -- 
> --Tim Ressel
> Circuit Abbey
> timr at circuitabbey.com
> 
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