[sdiy] Harmonic Sweetener: Jules Ryckebusch May 12, 2000

[NSSINC]

Thanks for looking!

Number one rule when something doesn't work has always blame yourself, 
what did you do wrong?

But I finally ran out of things I could be doing wrong.


I learned a little about op-amp filters in the process though.

-Al




On 11/17/24 09:08, Oren Leavitt via Synth-diy wrote:
> Yep! The op-amp filter (IC2 a/b) inputs are swapped in the PDF article. The positive feedback making them act like comparators with hysteresis.
>
>
> On Sunday, November 17th, 2024 at 9:41 AM, NSSINC <nssinc at hevanet.com> wrote:
>
>> Good morning,
>>
>> This circuit was posted here about 20 years ago...
>>
>> I tried it then and it didn't work for me, and I have just tried it
>> again with the same results.
>>
>> The filter section of the circuit (IC2) does not seem to operate as
>> intended.
>>
>> The output swings to one of the power supply rails and stays there.
>>
>> Is there any chance the op-amp input polarity on the highlighted filter
>> section is inverted?
>>
>>
>> https://www.noyessoundstudio.com/files/JR_harmonic_sweetener_filter_hghlight.pdf
>>
>>
>> The filter circuit described here seems to indicate as much:
>>
>>
>> https://www.noyessoundstudio.com/files/all_about_circuits_detail.jpg
>>
>> From-
>> https://www.allaboutcircuits.com/video-tutorials/op-amps-low-pass-and-high-pass-active-filters/
>>
>>
>> And my first attempt at dong a spice simulation reflects what I'm seeing
>> in the real world. It works ok if I swap the input polarity, but latches
>> to the rails as drawn.
>>
>> https://www.noyessoundstudio.com/files/simulide_filter_working.jpg
>>
>> https://www.noyessoundstudio.com/files/simulide_filter_NOT_working.jpg
>>
>>
>> I swear, way back in the day I built it on breadboard from the actual
>> article in Electronic Musician and it worked great. I have yet to find
>> my copy of the article or one on the web.
>>
>> Looking for a sanity check, is it me??
>>
>> Thanks for taking a look.
>>
>>
>> -Al
>>
>>
>>
>>
>>
>>
>>
>> ________________________________________________________
>> This is the Synth-diy mailing list
>> Submit email to: Synth-diy at synth-diy.org
>> View archive at: https://synth-diy.org/pipermail/synth-diy/
>> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
>> Selling or trading? Use marketplace at synth-diy.org
> ________________________________________________________
> This is the Synth-diy mailing list
> Submit email to: Synth-diy at synth-diy.org
> View archive at: https://synth-diy.org/pipermail/synth-diy/
> Check your settings at: https://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org