The smArTT verter is a simple but very effective utility module (known in the modular world as attenuverter) for scaling the level, polarity and DC offset of audio and CV signals.
Why another atenuverter considering that there are several ones in existence? As musicians we used variations on the atenuverter theme and our practical experience showed us that there are some aspects where things can be improved to make it more versatile.
Will try to draw to your attention the aspects where our smArTT verter is different (and in our opinion a better one).
1)- most atenuverters have the signal level pot used to change the level from maximum inverted at CCW (counter clockwise), zero at center to maximum non inverted at CW (clockwise). This solution has three disadvantages. The dynamic range of the inverted and non inverted signal takes the whole mechanical range of the potentiometer so it makes it harder to dial in precisely the level you want in some critical situations. The second disadvantage is that because of the tolerances of pots and parts, your signal zero will not be exactly where the mechanical zero (mid position) should be. The third disadvantage is, the signal zero has a very narrow range and sometime you really need your signal to be reduced in a performance to zero fast, easy and precisely.
We solved the three problems with a switch. In one position the signal has a range from zero to maximum noninverted, associated to the whole angular range of the pot. In the other position the signal has a range from zero to maximum inverted and it is also associated to the whole angular range of the pot. This way we solved all three problems: the whole mechanical range of the pot is used in a much more efficient way and the zero signal is really zero and easy to dial in.
2) - most atenuverters that have a DC offset option use the mechanical range of the pot to cover the range from negative DC (at CCW) to 0V (centre) to positive DC (at CW). The disadvantage is the DC zero is extremely narrow and hard to dial in.
We used a smart little trick to make that centre zero gap a bit larger and easier to dial in.
3) - several times when using an atenuverter we discovered that we had to use multiples to distribute the processed CV/audio signal to various modules . We decided to use three outputs, so you don't need to sacrifice a multi to distribute the processed signal.
The smArTT verter is the result of what we think the best set of features for an atenuverter in Eurorack format.
What our smArTT verter is not. Our smArTT verter can scale audio and CV signals for modulation and audio purposes but it is not recommended for precise 1V/octave pitch control. Of course you can use it to drive oscillators but if you need precise 1V/octave, you need a different circuit. Also our smArTT verter has the build out resistor outside the negative feedback. This is not an error, it was an intentional design decision.
The smArTT verter also has a bicolour LED for visual information about signal level and DC offset.
Specs & Downloads
Specs & Downloads
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