Attenuator – Inverter

The attenuator – inverter is a tool for modifying a voltage, Control Voltage (CV) or any audio signal.

It’s a simple mathematical function : Vout = a x Vin, where “a” varies between -1 and 1, depending on the cursor position:

Cursor VS. Output Multiplier
Vout = a x Vin
Vin VS. Vout
Blue line: Cursor at 100% (full clockwise)
Red line: Cursor at 75%
Black line: Cursor at 50% (center position)
Green line: Cursor at 0% (full anti-clockwise)

It is great, for example, for modifying the amount of CV you want to apply to your VCF cutoff freq. or your VCA : Full clockwise, your CV is x 1 (unchanged). Full Anti Clockwise, your CV is reversed (x -1) :
If you link your Envelope generator to your VCF, the Cutoff frequency will increase as your envelope CV increases.
With the inverter/attenuator inserted between the Envelope gen and the VCF, the Cutoff Freq. will either increase slowly, or even decrease if you turn the cursor anti clockwise.

It’s also usefull for reversing a LFO signal (decreasing ramp instead of increasing ramp).

As usual, you’ll find bare PCBs, complete kits and fully assembled and tested modules on tindie!


I sell on Tindie

Direct order (shipping costs included):

You MUST send me an email or leave a message to confirm your order (quantity, details…), and your postal address. If you don’t, I won’t be able able to send your order 🙂 Thank you!
PCB Only 6€
Kit PCB+Components 14€
Fully assembled 20€

Downloads

inverter 1.0b schematics
BOM & Documentation ver.20160523

2 thoughts on “Attenuator – Inverter

  1. Salut David… c’est Pedro, de Los Angeles… petite question [et SVP, mes excuses pour mon ignorance]: Comment peut on connecter ce petit Att/Inv dans le contexte d’un sistéme Eurorack? [Input, output, power]… Mais, espécialement si Je veut l’utiliser en “remote-mode”, c’est a dire, en dehors du “case” eurorack? [Je voudrais le prolonger avec des cables et le monter dans mon contrôleur à vent analogique, par example…] ..Merci en avance!

    1. Salut Pedro !
      Désolé pour la réponse tardive, je suis en plein déménagement ! ^^’
      J’ai mis à jour la petite documentation fournie avec le kit : http://www.davidhaillant.com/wp/wp-content/uploads/inverter-1.0b-smd-BOM-doc-20160523.pdf
      Peut être auras tu la réponse à ta question ?
      Le plus important est d’alimenter le module avec une tension double (+12V et -12V, plus la masse (gnd)), la même qui est fournie par l’alimentation de ton “case” (boitier).
      Dis moi si tu as besoin de plus d’explications. 🙂
      David.

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