{"id":4469,"date":"2021-09-22T15:07:15","date_gmt":"2021-09-22T20:07:15","guid":{"rendered":"https:\/\/pugix.com\/synth\/?p=4469"},"modified":"2023-02-15T13:34:30","modified_gmt":"2023-02-15T18:34:30","slug":"dubernator-ciat-lonbarde-filter","status":"publish","type":"post","link":"https:\/\/pugix.com\/synth\/dubernator-ciat-lonbarde-filter\/","title":{"rendered":"Dubernator – Ciat-Lonbarde Filter"},"content":{"rendered":"\n
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Another Ciat-Lonbarde PC board from crucFX, a.k.a. Josh Rodriquez, with circuit design by Peter Blasser. Dubernator is a dual bandpass filter, highly resonant. It features two identical, independent filters, each with cutoff and resonance pots and normal and inverting CV inputs for cutoff frequency. A third input mixes with the other inputs to both channels. A third output is a mix of the two outputs. The outputs are orange banana jacks, the inputs gray, CV inputs blue.<\/p>\n\n\n\n

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Assembled Dubernator<\/figcaption><\/figure>\n\n\n\n

I made a case from 1\/8 inch thick plexiglass for the top and bottom panels, just as I’ve done for the large Tetrazzi and the DIY Quantussy. A local glass business cuts these to my specification for a very reasonable price. Holes must be drilled at a low speed to avoid melting.<\/p>\n\n\n\n

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Top panel with power inlet super-glued on (right side)<\/figcaption><\/figure>\n\n\n\n

More Construction Photos<\/h3>\n\n\n\n

The only modification I made was to add 10K resistors in series on the two individual outputs. Peter always does this, so it must have been a mistaken omission when he drew the schematic that Josh worked from.<\/p>\n\n\n\n

The bypass capacitor on the input to the 9 volt regulator was specified at 2200uf by Peter. I found a 1000uf 25 volt cap only 3\/4 inch high that I knew would clear the one inch spacing I put between the board and the panel with nylon standoffs. Luckily it cleared the input banana jacks. I laid out the panel without taking it into consideration!<\/p>\n\n\n\n

I ordered polystyrene capacitors for the filter integrators, Mouser 23PS210. These are axial packages. You can see them standing on end in the photos.<\/p>\n\n\n\n

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Top of soldered board<\/figcaption><\/figure>\n\n\n\n
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Bottom of soldered board, showing added bypass capacitors<\/figcaption><\/figure>\n\n\n\n
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Panel fitted but not wired<\/figcaption><\/figure>\n\n\n\n
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Everything clears – yay! Including the huge capacitor.<\/figcaption><\/figure>\n\n\n\n
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Bottom after full assembly showing power inlet<\/figcaption><\/figure>\n\n\n\n
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Full assembly showing 1000uf power inlet capacitor<\/figcaption><\/figure>\n\n\n\n

Peter B’s Dubernator Schematic<\/h3>\n\n\n\n
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Test setup and demo recordings<\/h3>\n\n\n\n
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Large Tetrazzi patched to Dubernator for testing<\/figcaption><\/figure>\n\n\n\n

A very simple patch: one Tetrazzi ramp wave output to the “both” filter input. Filter outputs go to left and right recording inputs. For the first test I demonstrate self-oscillation of the filters. They can get raunchy sounding and go to pretty low pitches. To oscillate, the resonance is turned all the way up. I then manually twiddled the frequency knobs.<\/p>\n\n\n\n