{"id":3501,"date":"2020-02-26T11:16:07","date_gmt":"2020-02-26T16:16:07","guid":{"rendered":"https:\/\/pugix.com\/synth\/?p=3501"},"modified":"2021-09-15T07:50:03","modified_gmt":"2021-09-15T12:50:03","slug":"erica-synths-diy-swamp","status":"publish","type":"post","link":"https:\/\/pugix.com\/synth\/erica-synths-diy-swamp\/","title":{"rendered":"Erica Synths DIY Swamp"},"content":{"rendered":"\n
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SynthCube was having a sale, so I picked up a DIY kit<\/a> for Erica Synths DIY Swamp<\/a>. It’s a version of Grant Richter’s Wogglebug circuit. I can’t believe it’s been twelve years since I designed and built my own Wogglebug<\/a> circuit from information Grant had posted online. I guess I’m lucky, because Erica Synths is changing their DIY line<\/a>.<\/p>\n\n\n\n

Parts Acquisition<\/h3>\n\n\n\n

From SynthCube I bought the PC boards, Panel, and special sample and hold IC (ALPHA 1100CK2), which Erica Synths chose instead of the usual LF398. The remaining parts are quite standard and in fact I found all of the 1\/4 watt resistors in my stock, plus most of the capacitors and the vactrols. The rest were easily ordered from Mouser.com. The pots, jacks, switches, and knobs came from Thonk<\/a>. Thonk carried the exact knobs that Erica Synth uses. The only variance from the specified parts is that I used knurled jack nuts instead of hex nuts. I have a special wrench for the knurled nuts and I like the look better.<\/p>\n\n\n\n

Block Diagram<\/h3>\n\n\n\n

I drew my own block diagram for the module for ease of seeing the differences from other Wogglebugs, including my own.<\/p>\n\n\n\n

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Swamp Block Diagram<\/figcaption><\/figure>\n\n\n\n

Erica Synths added two features: the tone outputs from the 4046 oscillators can be switched between square and sawtooth waveforms; an external audio input to one side of the ring modulator (digital XOR) that replaces the square tone from the swamp oscillator.<\/p>\n\n\n\n

Also of note: the input to the sample and hold is a mix of three sources. The smooth saw tone is cross faded with the S&H output (the cluster function) with a panel control, but the swamp CV output is also mixed in.<\/p>\n\n\n\n

The only missing feature is an input jack for the S&H to override the internal sources.<\/p>\n\n\n\n

Construction<\/h3>\n\n\n\n

The module was very easy to build, consisting of all through hole parts. The two circuit boards sandwich together with header pins and sockets on each side. Somewhat unusual is that the parts side faces outwards on each boards. I used organic, washable solder (Kester 331) for all of the work, except for the pots, switches, jacks and LEDs, which went on last.<\/p>\n\n\n\n

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Swamp Main Board<\/figcaption><\/figure>\n\n\n\n
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Swamp Controls Board<\/figcaption><\/figure>\n\n\n\n
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Swamp Assembled<\/figcaption><\/figure>\n\n\n\n

Demo Recordings<\/h2>\n\n\n\n

The filter used was the Vult Freak stereo filter in various modes.<\/p>\n\n\n\n