[sdiy] SSM2044 Frequency Range

[Terry Shultz]

Hi Dan,

I worked with Ron Dow on the Proto-board at SSMT in Santa Clara while employed by E-Mu. I used to 
help him build up test boards and build the test fixtures on occasion.

I have several SSM2044 devices I keep for reference in my parts inventory.

I could probably get my proto-board out and make some plots on my Audio Precision but these are pretty old devices and the caps on my board are the same vintage.

If I still have this board out in my storage area, I’ll let you know. Some chips were made bu Exar and others at Interdesign I believe. Exar units were older and had some
process deviation that made it a bit interesting at times. I usually built batches of boards from the same run of chips and tend not to mix up date codes etc.

Perhaps you guys can tell me your date codes and I will see if I still have some of the same dated product. I have about a  hundred of these devices spanning several builds that I bought 
about 30 years ago.

I have a software version of this chip in DSP56k code and it is much more stable for my needs. Perhaps a Sigma DSP would be a good device to replace this function ??

Anyway Best regards,

Terry Shultz


> On Sep 3, 2015, at 8:41 PM, Dan Snazelle <subjectivity at hotmail.com> wrote:
> 
> By the way 
> 
> Is this on pcb or breadboard ?
> I've seen dirty flux boards kill a filters range and ive seen breadboards do crazy things too 
> 
> Ive always had great luck with 2044
> 
> 
> 
> 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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