Opamp question

[kxspxr]

I have a few questions about the 555 Modifier found in Beavis Audio's Armageddon Processor: http://www.beavisaudio.com/projects/ArmageddonProcessor/

I would like to substitute the LM386 for an opamp and add a small LFO section to control pin 5 on the 555. If I use a dual opamp where the first acts as buffer for the input signal and the next as a non inverting amp with a variable gain from 20 to 200, would it still (at least in theory) work? I'm thinking of using a TL072. I've had one two many projects failing to work properly lately, that's why I'm asking..

-Kasper

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[JovianPyx]

My own guess as someone who has used 555s in analog synth circuits is "yes".

My suggestion is this: The circuit is simple enough to breadboard on solderless breadboard or stripboard or vector board or whatever you use.

Just try it and see.

One thing I would do - use a 7555 timer, not a 555. Pinout is identical, but the device is CMOS and won't nail your power supply with a huge current spike each time it resets as a bipolar 555 timer will. This spike is the source of the VCOs in a FatMan wanting to lock together (soft synch) when the VCO pitches are close together. I've used part number ICM7555.

[kxspxr]

[kxspxr]

The 555 Modifier sounds great with the LM386. - so I built the PWM Fuzz from the Armageddon too. Sounds awesome! Two nice and easy builds both with their own (very) unique fuzz sound!

-Kasper