[sdiy] SSM2040 vs CEM3320

[René Schmitz]

On 02.11.2023 13:07, René Schmitz wrote:
> On 02.11.2023 11:15, Andrew Simper via Synth-diy wrote:
>> I've already done detailed modelling on the SSM2040 and posted a 
>> video to youtube on this model being matched to the LA67 Maca filter 
>> that uses the SSI2140.
>>
>> Can you please post links to the internals of the CEM3320?
>
> https://patents.google.com/patent/US4004141A/en
>
> Its different from the 2040 in so far that it has logarithmic shaping 
> before an OTA. ("linearising diodes")
>
> The OTA core is very similar to the arrangement in the 2040. But the 
> control and audio inputs are realized differently.
>
Opps, that should read LM13700 or CA3080. Its a three ball not a one 
ball OTA.
>
> I've been pondering about this: How can this be patentable, if this is 
> so similar in its working principle, and all the parts had been used 
> elsewhere.
>
>
> Best,
>
>  René
>
>
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